[Viral superantigens]. / Viral süperantijenler.

Superantigens (SAgs) are microbial proteins produced by various microorganisms that elicit excessive and strong stimulation of T cells via an unconventional mechanism. They cause polyclonal activation of T cells in a non-specific manner, by binding to a particular variable-beta (Vß) chain of T-cell receptor (TCR) and MHC class II molecule, in unprocessed form and outside of peptide-binding cleft, forming a bridge between the antigen presenting cell and the T cell. SAgs are classified into three groups, namely 1) exogenous (soluble proteins and exotoxins secreted by microorganisms), 2) endogenous (transmembrane proteins encoded by viruses which are integrated into the genome) and 3) B-cell SAgs (proteins which stimulate predominantly B cells). The best characterized and mostly studied SAgs are staphylococcal and streptococcal exotoxins, however it is well-known that many other microorganisms also possess SAg activities. Despite the presence of several viruses that cause severe infections in humans, the number of viruses that have proteins identified with SAg property in their pathogenesis, is relatively low. To date, the defined viruses that encoded SAgs are as follows; mouse mammary tumor virus (MMTV) (Marrack, et al. 1991), rabies virus (Lafon, et al. 1992), Epstein-Barr virus (EBV) (Sutkowski, et al. 1996), human endogenous retrovirus (HERV) (Conrad, et al. 1997), human immunodeficiency virus (HIV) (Posnett, et al. 1995; Torres, et al. 1996; Townsley-Fuchs, et al. 1997) and Ebola virus (Leroy, et al. 2011). SAgs were first described in the MMTV, a polymorphic B-type retrovirus that is either contained in the genome as an endogenous provirus (germline transmission) or exogenous infectious virus that transmits vertically via breast milk. Both MMTV forms encode SAgs. The SAg-mediated massive T cell activation is required for the spread of exogenous MMTV from intestines to mammary glands, facilitating the transmission of infectious virus. On the other hand, expression of endogenous SAgs leads to thymic deletion of responding T cells (bearing Vß6-9+ TCR) due to self-tolerance induction during the fetal life, and protects the host against future exogenous MMTV infections. The SAg of rabies virus is the N protein found in nucleocapsid structure and stimulates Vß8+TCR-bearing T cells. The SAg-induced polyclonal activation of T cells leads to turn-off the specific immune response, to enhance the immunopathogenesis and facilitates viral transmission from the initial site of infection (the muscle tissue) to the nerve endings. In case of EBV-associated SAg that activates Vß13+TCR-bearing T cells, it was detected that the SAg activity was not encoded by EBV itself, but instead was due to the transactivation of HERV-K18 by EBV latent membrane proteins, whose env gene encodes the SAg (Sutkowski, et al. 2001). It has been denoted that EBV-induced SAg expression plays a role in the long-term persistence and latency of virus in memory B cells, in the development of autoimmune diseases and in the oncogenesis mechanisms. The proteins which are identified as SAgs of HIV are Nef and gp120. It is believed that, the massive activation of CD4+ T cells (selectively with Vß-12+, Vß-5.3+ and Vß-18+ TCRs) in early stages of infection and clonal deletion, anergy and apoptosis of bystander T cells in the late stages may be due to SAg property of Nef protein, as well as the other mechanisms. However there are some studies indicating that Nef does not act as a SAg (Lapatschek, et al. 2001). HIV gp120 glycoprotein is a B-cell SAg that binds to VH3-expressing B cell receptors and causes polyclonal B cell activation. In addition, binding of gp120 to IgE on the surface of basophiles and mast cells causes activation of those cells, secretion of high level proinflammatory mediators leading to allergic reactions and tissue damage. In a recent study, the depletion (anergy or deletion) of T cell populations bearing Vß12+, Vß13+ and Vß17+ TCR have been shown, in patients infected with Zaire Ebola virus, whatever the clinical outcome (death or recovery), these results also suggest the presence of SAg activity. In this review article, following a brief description of the general characteristics of SAgs, virus-encoded SAgs and their roles in the diseases have been discussed.

Prospective investigation of the impact of West Nile Virus infections in renal diseases.

An increased incidence of chronic kidney disease (CKD) after West Nile Virus (WNV) infections has been suggested but the association of WNV infections with renal damage remain inconclusive. This study was undertaken to characterize WNV infections in individuals with acute kidney injury (AKI) and CKD, and to evaluate hemodialysis as a probable transmission route. A total of 463 plasma and urine samples were collected from 45 AKI and 77 CKD patients. Nested and real-time polymerase chain reaction (PCR) assays were employed for viral RNA detection. Specific immunoglobulins were investigated via immunofluorescence and plaque reduction neutralization assays. Consecutive pre and post-dialysis samples were evaluated in CKD cases. WNV RNA and specific immunoglobulins were detected in 7 (5.7%) and 5 (4.1%) individuals, respectively. The AKI patients with WNV RNA in blood and urine had underlying diseases requiring immunosuppressive therapy and demonstrated moderate to high viral loads. No clinical symptom related to WNV infection were observed in CKD cases with detectable viral nucleic acids. All WNV sequences were characterized as lineage 1 clade 1a and several amino acid substitutions with unknown impact were noted. Detailed epidemiologic investigation of WNV RNA positive CKD cases revealed probable vector-borne virus exposure, without the evidence for transmission via hemodialysis.

[Investigation of the hepatitis E virus seroprevalence in cases admitted to Hacettepe University Medical Faculty Hospital]. / Hacettepe Üniversitesi Tip Fakültesi Hastanesine basvuran olgularda hepatit E virusu seroprevalansinin arastirilmasi.

Hepatitis E virus (HEV), classified in Hepeviridae family, Hepevirus genus, is a non-enveloped virus with icosahedral capsid containing single-stranded positive sense RNA genome. HEV infections may be asymptomatic especially in children, however it may present as fulminant hepatitis in pregnant women, as well as chronic hepatitis in immunocompromised patients. There are four well-known genotypes of HEV that infect humans and many mammalian species. Genotype 1 and 2 are frequently responsible for water-borne infections transmitted by fecal-oral way in developing countries, while genotype 3 and 4 cause zoonotic infections in developed countries. Turkey is considered as an endemic country with a total seroprevalence rate of 6.3% for normal population, showing significant variation (0-73%) according to the regions and study groups. The aims of this study were to investigate the HEV seropositivity in cases admitted to Hacettepe University Medical Faculty Hospital (HUMFH), to evaluate the results according to the demographic features of patients, and to determine the current HEV seroprevalence in our region, contributing seroepidemiological data in Turkey. A total of 1043 serum samples (514 female, 529 male; age range: 1-90 years, mean age: 38.03) obtained from 327 blood donors (32 female, 295 male; age range: 19-59 years, mean age: 31.1) who were admitted to HUMFH Blood Center, and 716 sera (482 female, 234 male; age range: 1-90 years, mean age: 41.7) that were sent to HUMFH Central Laboratory from various outpatient/inpatient clinics, between November 2012 to November 2013, were included in the study. The presence of HEV-IgG antibodies in serum samples was detected by a commercial ELISA method (Euroimmun, Germany), and the presence of HEV-IgM antibodies was also investigated in the sera with IgG-positive results. The overall HEV-IgG seropositivity rate was determined as 4.4% (46/1043), and the seropositivity rates for blood donors and in/outpatients were as 0.92% (3/327) and 6.0% (43/716), respectively. HEV-IgM antibody was not detected in any of the cases. The HEV-IgG seropositivity was 3.2% among male, and 5.6% among female, yielding no statistically significant difference between the gender (p= 0.056). HEV-IgG antibodies were detected in none (0/118) of the pediatric age group (0-18 years), while the seropositivity rates were 1.9% (14/731) and 16.5% (32/194) in 19-55 and ≥ 56 years-old groups, respectively. The difference between the age groups was statistically significant (p< 0.001), indicating the age-related pattern of HEV exposure. In conclusion, the total HEV seroprevalence rate found as 4.4% in our study, is comparable to the average results reported from Turkey. Our data is also in agreement with the result of a previous report (3.8%) that performed from Ankara province in 2002 with similar study groups, emphasizing that there was no significant changes for HEV exposure have occured over more than the last decade in Ankara, Cental Anatolia, Turkey.

[New, newer, newest human polyomaviruses: how far?]. / Yeni, daha yeni, en yeni insan polyomaviruslari: Nereye kadar?

Polyomaviruses, classified in Polyomaviridae family, are non-enveloped small (40-45 nm) viruses with icosahedral symmetry and circular double-stranded DNA genome. Polyomaviruses can infect a variety of vertebrates including birds, rodents, cattle, monkeys and humans. The characteristics such as establishment of latent infections, reactivations during immunosuppression and oncogenic potencies render the human polyomaviruses (HPyVs) of considerable importance for public health. The first polyomavirus (Mouse polyomavirus) has been identified in 1953 as filterable tumor-causing agents in mice, followed by Simian vacuolating virus (SV40) isolated from rhesus monkey kidney cells that had been used for poliovirus vaccine preparation in 1960. Due to the known transforming capacity of SV40, it was initially thought that the incidence of cancer could increase following the administration of SV40-contaminated polio vaccines, however advanced studies yielded inconsistent results, without any evidence to conclude whether or not the contaminated polio vaccine caused cancer. Several studies have reported the detection of SV40 genome in some of the human tumors, as well as in the clinical samples of healthy subjects. In addition SV40 seropositivity was reported in human populations although in low rates (2-10%). These data have raised the possibility that SV40 infects humans and circulates in human populations unrelated to being exposed to the vaccine. The discovery of the first human polyomaviruses was in 1971 independently from each other, one was BK virus (BKPyV) isolated from the urine sample of a renal transplant patient, and the other was JC virus (JCPyV) isolated from the brain tissue of a patient with progressive multifocal leukoencephalopathy, and both were named after the patients' initials. BK and JC viruses were the only well-known human polyomaviruses throughout 36 years, however drammatical increase in number of newly identified human polyomaviruses was recorded in the last six years due to the use of sophisticated molecular methods and new-generation sequencing technologies. In 2007, two new HPyVs were identified independently from nasopharyngeal aspirates of children with acute respiratory tract infections; one was KI (Karolinska Institute) and the other was WU (Washington University) polyomaviruses, named after the initials of institutes which they were first described. In 2008, the fifth HPyV namely Merkel cell polyomavirus (MCPyV) was isolated from the skin tumor sample of a patient with Merkel cell carcinoma. In 2010, three other novel human polyomaviruses were discovered, two were from skin samples of healthy subjects (HPyV-6 and HPyV-7), and one (Trichodysplasia Spinulosa-associated virus; TSPyV) from keratotic spicule sample of a heart-transplanted patient. Another new HPyV was identified in 2011 named HPyV-9, from the blood and urine samples of an asymptomatic patient with kidney transplant. Most recently, three new HPyVs have been sequentially discovered during the last quarter of 2012. The 10th HPyV (HPyV10) was identified in condyloma samples of an immunocompromised patient with WHIM syndrome (Wart, Hypogammaglobulinemia, Infections, Myelokathexis), 11th virus was isolated from stool sample of a healthy child from Malawi (Malawi polyomavirus; MWPyV), and 12th was described from fecal sample of a diarrheal child from Mexico (Mexico polyomavirus; MXPyV). The whole genome sequence analysis of HPyV10, MWPyV and MXPyV pointed out that they are closely related viruses. The last novel polyomavirus, namely Saint Louis polyomavirus (STLPyV) has been reported in a study published on February 2013, identified from the stool sample of a healthy child. Seroepidemiological studies indicated that most of the novel HPyVs are highly prevalent (average rate: 40-80%) worldwide and likely acquired asymptomatically during childhood, similar to the old ones, BKPyV and JCPyV. However data about HPyV10, MWPyV, MXPyV and STLPyV are not enough as they have been discovered most recently. Similarly, little is known about the pathogenesis, route of infection and the relationship with clinical diseases of novel HPyVs except MCPyV and TSPyV which are known to be responsible for Merkel cell carcinoma and trichodysplasia spinulosa, respectively. The expanding repertoire of human polyomaviruses made us think that many others will be uncovered in the future thanking to the advances in molecular methods. In this review, recent developments subjecting new human polyomaviruses have been summarized.

[Detection of resistance mutations in chronic hepatitis B patients receiving antiviral therapy for over one year]. / Bir yildan uzun süreli antiviral ilaç kullanan kronik hepatit B hastalarinda direnç mutasyonlarinin saptanmasi

Primary mutations conferring hepatitis B virus (HBV) antiviral resistance and associated secondary/compensatory mutations were investigated in this study by DNA sequencing (SEQ) and two commercial Line Probe Assays (LiPAs) (Inno-Lipa HBV DRv2 and Inno-Lipa HBV DRv3, Innogenetics, Belgium). A total of 71 subjects under follow-up for chronic hepatitis B and receiving lamivudine (LVD) therapy for one year or longer at the Hacettepe University Faculty of Medicine, Department of Internal Medicine, Gastroenterology Unit were included in the study with informed consent. Male to female ratio and mean age was noted as 47/24 and 43 ± 15.8 (age range: 13-71) years, respectively. Twenty samples with low HBV DNA levels (mean: 204.6 IU/ml) could not be interpreted by SEQ due to insufficient amplification. All samples with a positive consensus PCR were further analysed via LiPAs, as directed by the manufacturer. Thus a total of 51 and 56 samples could be evaluated via SEQ and LiPA assays, respectively. In 13 of the 51 (25.5%) samples by SEQ and in 9 of 56 (16%) samples by LiPAs, primary and compensatory mutations associated with resistance were identified. Multiple mutations that comprise L180M + M204I in four and L180M + M204V in one sample and single mutations (M204I) in three samples were identified by SEQ. In one sample which had multiple mutations associated with LVD resistance single mutations (S202G, N236T) associated with entecavir resistance and in two other such samples mutations associated with adefovir resistance were detected by SEQ. Also, in three samples amino acid substitution at position rt215 (QÆS) as alone and in one sample with multiple mutations were observed via SEQ. In five of nine samples primary and compensatory multiple mutations (L180M + M204I in one sample, L80I + L180M + M204I in two samples, L80I/V + M204I in one sample) and primary single mutations associated with LVD resistance (M204I/V) in four samples were detected by Inno-Lipa HBV DRv2. Two different mutations (G202, ILFM184) were observed in two samples with multiple mutations associated LVD resistance via Inno-Lipa HBV DRv3. However, mutation at position rt184 was evaluated as a weak positive. Any mutation associated with adefovir resistance was not detected by LiPA. As a result, SEQ and LiPAs displayed comparable performances for the detection of HBV drug resistance mutations. We suggested that for the evaluation of discordant results, it should be better to test consecutive serum samples.

[Investigation of baseline antiviral resistance in treatment-naive chronic hepatitis B cases]. / Tedavi Naif Kronik Hepatit B Olgularinda Bazal Antiviral Direncin Arastirilmasi

Naturally-occurring mutations associated with resistance to nucleoside/nucleotide analogues (NA) can be detected in a group of treatment-naive individuals chronically infected with hepatitis B virus (HBV). Genotypic resistance testing prior to the initiation of NA therapy may facilitate the selection of optimal drug regime and help to prevent early emergence of clinical resistance. In this study, presence of resistance mutations in treatment-naive individuals with chronic hepatitis B (CHB) was investigated in Hacettepe University Hospital, a referral center in Ankara province, Turkey. A total of 42 patients (17 female, 25 male; age range: 18-62 years) diagnosed as CHB were enrolled in the study with informed consent. All of the patients were negative for hepatitis C and D viruses and human immunodeficiency virus coinfections, and none had a history of interferon or NA treatment. HBV viral load, HBV markers and hepatic enzymes in patients were determined via standardized commercial assays. For the detection of NA resistance mutations, a partial sequence of approximately 250 nucleotides, harboring the frequently-observed sites for NA resistance was amplified via nested PCR and characterized by direct sequencing of the amplicons. The sequences were handled and interpreted for the presence of mutations via various softwares and a web-based virtual phenotyping tool. Well-characterized sequences were obtained in 30 out of 42 samples (71.4%). All circulating HBV strains were observed as genotype D. Nucleotide variations were detected in 19 individuals (63.5%) that comprise silent mutations without amino acid substitution in 8 (26.6%), mutations with undetermined significance in 7 (23.3%) and mutations associated with NA resistance in 3 (10%) patients. Mutations conferring resistance to entecavir + lamivudine (S202G, M204V, L180M, T184N) were identified in one patient whereas L180P, A181Q and A194V substitutions associated with probable lamivudin + adefovir and tenofovir resistance, respectively, were detected in other patients. All patients with resistance mutations were HBsAg and HBeAg positive, anti-HBe negative and had viral loads exceeding 3 x 10(7) IU/ml. In two patients, the route for HBV transmission was vertical. Since no follow-up samples were available from individuals with resistance mutations, alterations in serological markers, viral load and mutation patterns could not be monitored. In conclusion, the presence of NA resistance mutations were revealed in treatment-naive CHB cases in a referral hospital in Turkey. The impact and cost-effectivity of detecting naturally-occurring resistance mutations for clinical follow-up prior to the antiviral therapy need to be elucidated by prospective studies.

[Investigation of West Nile virus seroprevalence in Hacettepe University Hospital blood donors and confirmation of the positive results by plaque reduction neutralization test]. / Hacettepe Üniversitesi Hastanesi Kan Donörlerinde Bati Nil Virusu Seroprevalansinin Arastirilmasi ve Pozitif Sonuçlarin Plak Redüksiyon Nötralizasyon Testi ile Dogrulanmasi

West Nile virus (WNV), a member of Flaviviridae family, is an enveloped, icosahedral, single-stranded positive-sense RNA virus. WNV is transmitted to humans by infected mosquitoe (especially Culex spp.) bites and cause a variety of clinical outcomes, ranging from asymptomatic infection to severe meningoencephalitis. The aims of this study were to determine and confirm the WNV seroprevalence in a chosen healthy population and to provide epidemiological data for Turkey about the recent status of the infection at our region. A total of 1200 serum samples collected from blood donors (400 were female, 800 were male; age range: 18-61 years, mean age: 37.8) who were admitted to Hacettepe University Hospital Blood Donation Center between April to December 2009, were included to the study. The presence of WNV IgG antibodies were screened by ELISA (Euroimmun, Germany), and the positive samples have been further investigated by WNV IgG avidity test in order to estimate the time of encounter to the virus. Indirect immunofluorescence antibody (IFA) test (Euroimmun, Germany) and plaque reduction neutralization test (PRNT) which is accepted as the reference method, were performed for the confirmation of WNV IgG positive results. Nineteen (1.6%) of the samples yielded WNV IgG positivity with ELISA, and all of which were IgGs with high avidities (Avidity index values were between 67.8-99.2%). Eight of 19 (42.1%) WNV ELISA IgG positive donors, had risk factors such as joining outdoor activities, contact with mosquitos and ticks and consuming raw milk and milk products. Of 19 samples that were taken into confirmation tests, 15 (78.9%) were found positive with IFA, and 10 (52.6%) were found positive with PRNT. WNV antibody positivity of 10 samples were then confirmed by PRNT, however eight samples which were found positive with both ELISA and IFA yielded negative results with PRNT. This data might indicate that ELISA and IFA methods in which virus-infected cells were used as substrates, have detected non-neutralizing antibodies against viral nucleocapsid antigens rather than the neutralizing antibodies detected against envelope glycoproteins by PRNT method. One sample which yielded low positive result only by ELISA test has been evaluated as a specificity issue of the test. As a result, the positivity rate (19/1200; 1.6%) of WNV IgG detected by ELISA in blood donors, has been confirmed as 0.8% (10/1200) by a gold standard method, PRNT. The data of this study indicated that the prevalence of WNV infections, although low in our region, deserves attention to be considered in surveillance and control programs related to WNV in Turkey.

[Investigation of dengue virus and yellow fever virus seropositivities in blood donors from Central/Northern Anatolia, Turkey]. / Orta/Kuzey Anadolu Bölgesi kan donörlerinde Dengue virusu ve sari humma virusu seropozitifliginin arastirilmasi

Dengue virus (DENV) and yellow fever virus (YFV) are two of the globally prevalent vector-borne flaviviruses. Data on these viruses from Turkey is limited to a single study originating from the western, Aegean region of Turkey, where evidence for DENV exposure had been confirmed in residents and presence of hemagglutination inhibiting antibodies against YFV had been revealed. The aim of this study was to investigate the rates of seropositivity of DENV and YFV in blood donors from Central/Northern Anatolia, Turkey, for the demonstration of possible human exposure. Serum samples were collected by the Turkish Red Crescent Middle Anatolia Regional Blood Center from donation sites at Ankara, Konya, Eskisehir and Zonguldak provinces and included in the study after informed consent. Ankara is the capital and second most-populated city in Turkey. All samples were previously evaluated for West Nile and tick-borne encephalitis virus antibodies and found to be negative. A total of 2435 and 1502 sera have been evaluated for IgG antibodies against DENV and YFV, respectively. Commercial enzymelinked immunosorbent assays (ELISAs) and indirect immunofluorescence tests (IIFTs) were applied (Euroimmun, Germany) for DENV/YFV IgG surveillance. DENV IgG reactive sera were further evaluated for IgM by ELISA and a commercial mosaic IIFT to determine DENV subtypes. IgM positive samples were also analyzed by a commercial NS1 antigen detection assay (Bio-Rad Laboratories, France). YFV IgG reactive samples were evaluated by IIFT for IgM and via mosaic IIFT and antibody specificity were confirmed by plaque reduction neutralization test (PRNT). Anti-DENV IgGs were demonstrated in repeated assays in 0.9% (21/2435) of the sera. In two samples with borderline IgG results, presence of DENV IgM was detected, one of which was also borderline positive for DENV NS1 antigen. In 14.3% (3/21) of the IgG reactive sera, mosaic IIFT was evaluated as positive and displayed prominent reactivity for DENV-2 in all samples. From five donors with DENV reactivity, new samples were obtained after at least six months which revealed the continuing presence of DENV IgG activity in four. One sample which was initially positive for IgM, borderline for NS1 antigen and borderline for IgG was observed to be positive for IgG and negative for IgM in redonation. IIFT results in three redonation samples also indicated reactivity for DENV-1 and DENV-2 subtypes. Anti-YFV IgGs were detected in 0.6% (9/1502) of the sera. YFV IgM could not be demonstrated in any of the IgG reactive samples and PRNT was evaluated as negative. In conclusion, evidence for DENV exposure, presumably to DENV-2, was identified in residents from Central Anatolian provinces of Ankara and Konya for the first time, however, seroreactivity detected against YFV could not be confirmed by PRNT. These findings indicated that DENV or an antigenically-similar flavivirus was probably present in the study region and sporadic human exposure might have occurred.

[Investigation of West Nile virus in central nervous system infections of unknown etiology in Ankara, Turkey]. / Ankara bölgesinde nedeni bilinmeyen merkezi sinir sistemi enfeksiyonlarinda Bati Nil virusunun arastirilmasi.

Arthropod-borne viral infections have recently gained considerable attention and importance as re-emerging infections in a global scale. West Nile Virus (WNV), a member of Flaviviridae, is an enveloped positive strand RNA virus that is usually transmitted to humans by the bite of Culicine mosquitoes. Although the majority of the human infections are asymptomatic, WNV may also cause febrile and neuro-invasive diseases. Seroprevalence data from Turkey indicate that WNV activity is present in Central Anatolia. In this study performed at Hacettepe University Hospital, paired serum and cerebrospinal fluid (CSF) samples from 87 adult patients with the preliminary diagnosis of aseptic meningitis/encephalitis of unknown etiology were evaluated retrospectively to identify WNV-related syndromes. Bacterial, fungal and mycobacterial cultures yielded negative results and Mycobacterium tuberculosis and Herpes simplex virus nucleic acid tests were also negative for the selected patients. Commercial enzyme-linked immunosorbent assay (ELISA)s and indirect immunofluorescence test (IIFT)s were employed for WNV IgM and IgG antibody detection (Anti-WNV Virus IgG/IgM ELISA, Anti-WNV Virus IgG/IgM IIFT; Euroimmun, Germany). Additional ELISA/IIFT assays were further performed for WNV antibody reactive samples to identify cross-reactions and/or infections with other flaviviruses and phleboviruses. All WNV antibody positive samples were also evaluated by a WNV real-time reverse-transcription polymerase chain reaction (RT-PCR) assay. WNV IgM and IgG antibodies were detected in %9.2 (8/87) and 3.4% (3/87) of the serum samples, respectively. All IgG reactive samples were negative for IgM. All sera with WNV antibody reactivity (n = 11) and the corresponding CSF samples were negative for viral RNA via RT-PCR. In 5 of the 8 WNV IgM positive subjects, sandfly fever virus IgM antibodies were detected, which was also accompanied by Dengue virus IgM positivity in one sample. In another case, intrathecal antibody synthesis against measles virus was demonstrated. Two cases (2/87; 2.3%) with WNV IgM positivity as the only serologic marker were identified as probable WNV infections and clinical features were discussed. In conclusion, in order to fully understand the impact of WNV and/or other flavivirus infections in Turkey, epidemiology and ecological features of these agents need to established.

Cytomegalovirus hepatitis and ganciclovir treatment in immunocompetent children.

Ganciclovir treatment in children with cytomegalovirus (CMV) infection is still controversial and only indicated in selected cases. The aim of thi study was to evaluate clinical and demographic features of CMV hepatitis in immunocompetent children and to determine the effect of ganciclovir treatment in these patients retrospectively. The study was carried out in a group o 29 children with CMV hepatitis. All the patients were investigated for signs of infection, inborn errors of metabolism, genetic diseases, extrahepatic biliary atresia and other causes of hepatitis. Two patients with congenital CMV infection and two patients with biliary atresia were excluded from the study group. The patients included in the study were divided into two groups: non-cholestatic hepatitis (n=16) as Group I and cholestatic hepatitis (n=9) as Group II. Four (25%) patients in the non-cholestatic group and four (44.4 in the cholestatic group were treated with ganciclovir for a median of 21 days. The mean age was 9.6+/- 10.9 months (median age 6 months) in Group I, while cholestatic hepatitis patients in Group II were significantly younger, with a mean age of 2.7+/-0.9 months (p<0.01). The most prominent symptoms at admission were diarrhea and vomiting (25%) in Group I. In Group I, all cases (100%) and in Group II, three of four cases (75%) treated with ganciclovir had recovery from acute CMV hepatitis. In the non-cholestatic group, no relapses were observed while one patient in the cholestatic group relapsed and progressed into chronic liver disease. Patients who received supportive treatment showed a marked decrease in GGT, ALT, AST and bilirubin levels spontaneously and no relapses of hepatitis were observed in at least one year of follow-up. Although ganciclovir therapy is not indicated particularly in immunocompetent cases, since most were self-limited infections, in case of progressive and persistent hepatitis, such as in our cases, ganciclovir was a treatment option; no side effect due to ganciclovir therapy was observed in our cases. Although ganciclovir seems to be effective in progressive CMV hepatitis, multicenter randomized studies in a large study group are necessar to determine the efficacy and indications for ganciclovir treatment.

[Cytokine storm in avian influenza]. / Kus gribinde sitokin firtinasi.

The most dramatic example of defining the pathogenicity of influenza virus A/H5N1 strains is the higher fatality rate of avian influenza epidemic (>50%) occured in Southeast Asia in 1997 comparing to the pandemic caused by influenza virus A/H1N1 in 1918 (5-10%) which was recorded as the most destructive pandemic in the world. When considering the fatal/total case numbers (208/340) reported by World Health Organization in respect of December 14th, 2007, the mortality rate has now reached to 61 percent. Recent studies have shown that the high fatality rate of avian influenza virus infections is a consequence of an overactive inflammatory response and the severity of infection is closely related with virus-induced cytokine dysregulation. The most important feature of A/H5N1 immunopathogenesis is the appearence of hypercytokinemia ("cytokine storm") which is characterized by the extreme (exaggerated) production and secretion of large numbers and excessive levels of pro-inflammatory cytokines. This phenomenon is blamed on the emergence of lethal clinical symptoms such as extensive pulmonary oedema, acute bronchopneumoniae, alveolar haemorrhage, reactive haemophagocytosis, and acute respiratory distress syndrome, associated with necrosis and tissue destruction. Numerous in vitro, in vivo and clinical studies have pointed out that A/H5N1 viruses are very strong inducers of various cytokines and chemokines [Tumor Necrosis Factor (TNF)-alpha, Interferon (IFN)-gamma, IFN-alpha/beta, Interleukin (IL)-6, IL-1, MIP-1 (Macrophage Inflammatory Protein), MIG (Monokine Induced by IFN-gamma), IP-10 (Interferon-gamma-Inducible Protein), MCP-1 (Monocyte Chemoattractant Protein), RANTES (Regulated on Activation Normal T-cell Expressed and Secreted), IL-8], in both humans and animals. The privileged cells of cytokine storm are macrophages and CD8+ T-lymphocytes, while the primary contributor cytokines are TNF-alpha, IL-6 and IFN-gamma. It has been detected that, mutations of some viral genes (NS1, PB2, HA and NA) are responsible for the cytokine storm, by increasing the viral replication rate, expending the tissue tropism, facilitating the systemic invasion and emerging of resistance against the host antiviral response. It has been shown that Glu92 and Ala149 mutations, and carboxyl-terminal ESEV/EPEV motif of NS1 protein have been implicated as determinants of virulence for A/H5N1 strains. In addition, Lys627 mutation in PB2 protein, polybasic aminoacid mutations in the cleavage region of hemagglutinin (HA) polyprotein, and glycosylation and sialylation mutations in HA and neuraminidase (NA) proteins were found to enhance the immune-mediated patology of highly virulent A/H5N1 strains. In this review article, the immunopathogenesis of influenza infection and the mechanisms of cytokine storm caused by influenza A/H5N1 viruses have been discussed under the light of recent literature.

[Investigation of anti-R7V antibodies in HIV-infected patients under highly active antiretroviral therapy]. / Yüksek düzeyde aktif antiretroviral tedavi alan HIV ile enfekte olgularda anti-R7V antikorlarinin arastirilmasi.

R7V is a seven-aminoacid peptide epitope derived from cellular beta-2 microglobulin, present on human immunodeficiency virus (HIV) virion surface in patients with HIV infection. Antibodies against R7V peptide have the property of neutralizing all strains of HIV, unrelated to genotype, phenotype, or geographical origin of the virus, even in the presence of anti-retroviral drug resistance. Patients that mount an anti-R7V antibody response have been shown to be slow or non-progressors and this epitope has been considered for vaccine and/or therapeutic uses. In this study, HIV-infected patients under highly active anti-retroviral therapy (HAART) at Hacettepe University Faculty of Medicine, Department of Internal Medicine, Division of Infectious Diseases, were evaluated for the presence of anti-R7V antibodies. Thirty-three HIV positive patients and 10 healthy controls were enrolled to the study. For HIV-infected patients, determination of viral load and CD4+ T lymphocyte counts were performed by a commercial real-time PCR assay and flow cytometry, respectively. Anti-R7V antibodies were detected from serum samples by a commercial ELISA (Anti-R7V ELISA, Ivagen, France) test. Three HIV infected patients (3/33, 9.1%) displayed anti-R7V antibodies whereas the remaining 30 (90.9%) patients and all controls were interpreted as negative. No statistically significant difference was detected for HIV-RNA levels and CD4+ T lymphocyte counts between anti-R7V positive and negative patients (p= 0.871 and p= 0.287, respectively). These results indicate the presence of anti-R7V antibodies in our study population with HIV infection. No correlation with the presence of anti-R7V and disease progression were displayed in this study. Clinical impact of anti-R7V antibody assays for the management of HIV-infected patients will be revealed in the near future with the help of advanced studies.

Seroprevalence of West Nile virus and tick-borne encephalitis virus in southeastern Turkey: first evidence for tick-borne encephalitis virus infections.

West Nile virus (WNV) and tick-borne encephalitis virus (TBEV) are among the medically important Flaviviruses that cause significant morbidity and mortality in humans. In this study, seroprevalence of WNV and TBEV in sera from two state medical hospitals from the southeastern part of Turkey was investigated. One hundred eighty-one serum samples were evaluated for WNV immunoglobulin G (IgG) by an indirect immunofluorescence test (IIFT) and for IgG antibodies against TBEV by a commercial enzyme-linked immunosorbent assay (ELISA) kit with enhanced sensitivity and specificity. Sera positive for WNV IgG were further analyzed by plaque reduction neutralization assay (PRNA). TBEV IgM was also investigated by ELISA in all seroreactive samples. Of 181 sera, 29 (16%) were positive for WNV IgG by IIFT and 17 of 179 (9.5%) were confirmed by PRNA. Nineteen of 181 (10.5%) sera were detected to have TBEV IgG. Mean titer of TBEV IgG was 43.0 RU/mL (median, 33.9 RU/mL; cutoff: 20 RU/mL). Four samples with WNV IgG antibodies were also positive for TBEV IgG antibodies. TBEV IgM was detected in 9 of 39 (23%) of all seroreactive sera, where IgM positivity were accompanied by IgG for 6 samples. These results suggest the presence of possible human WNV and TBEV infections in southeastern Turkey where vector activity have previously been detected.

[Investigation of Chlamydia trachomatis positivity in women with and without gynecologic complaints by cytologic and direct immunofluorescence methods]. / Jinekolojik yakinmalari olan ve olmayan kadinlarda Chlamydia trachomatis pozitifliginin sitolojik ve direk immonofloresans yöntemleriyle arastirilmasi.

The asymptomatic nature of the majority of Chlamydia trachomatis infections leads to persistent infections and serious complications as well as continuous transmission of bacteria in the populations. The aim of this study was to investigate the presence of C. trachomatis in non-pregnant women with and without gynecologic signs and symptoms, and to detect the rate of asymptomatic carriage. Cervical specimens collected from 200 nonpregnant women (age range: 20-81 yrs; mean age: 40.2+/-10.4 yrs) who were admitted to Gynecology and Obstetrics Clinics of Hacettepe University Hospital were included to the study. Of them 68 had clinical complaints such as vaginal discharge, itching/irritation, inflammation and inguinal pain, while 132 had not any clinical complaints. All the samples were examined by direct immunofluorescence (DFA) method (Fluorotect Chlamydia, Omega Diagnostics, UK) with fluorescein isothiocyanate labeled monoclonal antibodies against C. trachomatis serotype specific major outer membrane proteins, and the samples were simultaneously screened cytologically by Papanicolaou staining method. As a result, C. trachomatis antigen positivity was found in 49 (24.5%) of the samples by DFA method, and chlamydial inclusion bodies were detected in 19 (9.5%) of women by cytologic method. Twelve (24.5%) of the 49 DFA positive samples, and 7 (4.6%) of the 151 DFA negative samples yielded positive results cytologically. The observed proportion of overall agreement (P) was estimated as 78% between the results of methods. C. trachomatis antigen positivity was detected in 16.2% (11/68) and 28.8% (38/132) of women with and without clinical symptoms, respectively. There was no statistically significant difference between C. trachomatis positivity and neither the presence of clinical signs and symptoms nor the characteristics of the signs and symptoms (p>0.05). In conclusion, the high asymptomatic carriage rate detected in our study population indicated that, for the prevention of bacterial transmission in the populations, the women who were admitted to gynecology and obstetrics clinics should be screened for C. trachomatis positivity even if they had no clinical complaints. The use of DFA method together with the widely used, practical and economical cytologic examination method, would increase the sensitivity and specificity of C. trachomatis diagnosis.

Metabolic syndrome, non-alcoholic steatohepatitis (NASH), and hepatocyte growth factor (HGF).

BACKGROUND: Hepatocyte growth factor (HGF) is not only an antiapoptotic and antifibrotic factor of liver, but it is also an adipokine. Serum HGF levels are strongly associated with liver diseases, obesity, insulin resistance (IR), and metabolic syndrome (MS). Non-alcoholic steatohepatitis (NASH) is the hepatic component of MS. To the best of our knowledge, serum HGF levels in patients with NASH have not been previously studied. Our aim was to elucidate the correlation of HGF with the clinical and histopathological parameters of NASH. METHODS: The study group consisted of 26 patients (13 men) who had clinical diagnoses of NASH and underwent liver biopsies. Controls were 13 volunteers (3 men) with negative viral autoimmune markers, and with normal levels of serum lipids and liver enzymes. RESULTS: Among the NASH patients, 14(54%) were overweight and 10 (39%) had grade I-II obesity. All the patients had class 3-4 non-alcoholic fatty liver disease (NAFLD) except for 2 who had class 2 disease. All of the patients had Child's class A liver disease, and MS was present in 5 (19%) patients and 8(31%) patients had Homeostasis Model Assessment of Insulin Resistance (HOMA) > 3. Serum HGF levels were similar in NASH patients (1.24 +/- 1.09 pg/mL) and controls (0.86 +/- 0.22 pg/mL) (p = 0.21). The levels of serum HGF did not differ between the patients with or without MS (1.65 +/- 1.48 pg/mL and 1.04 +/- 0.80 pg/mL, respectively, p=0.65). HGF was not correlated with the laboratory or histopathological parameters. CONCLUSIONS: Serum HGF levels were higher in NASH patients than in the controls, although it was statistically insignificant and a correlation with MS could not be detected in this study.

[Herpes simplex virus vaccine studies: from past to present]. / Dünden bugüne herpes simpleks virus asi çalismalari.

The dramatical increase in the prevalence of Herpes simplex virus (HSV) infections and the significant physical and psychosocial morbidity of HSV type 2 infections, generate the need for an efficacious HSV vaccine. The most important properties of HSVs that should be targeted for a successful vaccine are neuronal invasion, latency and reactivation in spite of specific host immune responses. The major expectation for an ideal HSV vaccine candidate is to induce sterilizing immunity, which must be effective at all portals of HSV entry; to prevent or reduce the symptomatic disease and to eliminate or at least to limit the asymptomatic viral shedding. The first vaccine studies have began in the 1920s and in the intervening eight decades there have been many attempts to develop an effective one. Although encouraging findings came from experiments in various animal models, human studies have been disappointing, unfortunately. The vaccine strategies that have undergone clinical evaluation until today included autoinoculation of live HSV, whole inactivated vaccines, attenuated live virus vaccines, modified live virus subunit vaccines, cell culture-derived subunit vaccines, recombinant subunit (glycoprotein) vaccines, DISC (Disabled Infectious Single Cycle) virus vaccines, viral vectors and naked DNA vaccines. In most of the clinical studies the failure of HSV vaccines in spite of inducing very high levels of specific neutralizing antibodies have emphasized that cell-mediated immune response, especially Thl type immunity is important in preventing both primary disease and recurrences with HSV, rather than humoral response. The most hopeful result was obtained with HSV-2 gD and alum/MPL vaccine in clinical studies. This vaccine was found 74% effective in preventing genital disease in HSV seronegative women but was not effective in men or seropositive women. In recent years it is possible to genetically engineer HSV to produce a vaccine strain that is protective without causing human disease. An example for this strategy was the development of a live attenuated vaccine from which neurovirulence gene (gamma1 34.5) has been removed. Another promising one was the replication-defective DISC virus HSV vaccine which is derived from a virus with an essential gene (e.g. gH gene) deleted, so the replication has been limited only to a single cycle. As a result, intensive HSV vaccine trials are currently underway, although all the previous attempts to produce an effective vaccine for the prophylaxis and immunotherapy against HSV have been largely unsuccessful. In this review the history of HSV vaccine development together with the preclinical and clinical studies from past to present has been summarized and recent progress for an effective HSV vaccine together with the further improvements required for an immunogenic vaccine have been discussed.

Viral studies in the cerebrospinal fluid in subacute sclerosing panencephalitis.

OBJECTIVES: The pathogenesis of subacute sclerosing panencephalitis (SSPE), and particularly, the cause of measles virus (MV) reactivation following a latent period after primary measles infection is unknown. The hypothesis of other viruses contributing to the pathogenesis of SSPE by affecting the in vivo state of MV was investigated. METHODS: We examined the cerebrospinal fluid of SSPE patients (n=43) for DNA or RNA and antibodies against HSV type 1 and 2, EBV, CMV, VZV, Hepatitis B, Hepatitis C, JC virus, human herpesvirus (HHV)-6, HHV-7, HHV-8, HTLV-1, and HTLV-2. We compared the findings with those of patients with other neurological disorders (n=39). RESULTS: CMV DNA and HSV type 1 IgG were found more frequently in SSPE patients. Other positive results were at similar incidence in SSPE and control groups. The clinical features of SSPE cases with and without positive viral tests did not differ from each other. CONCLUSION: These data do not support a specific role for these agents in SSPE, but imply that the passage of some viruses to the CNS and local antibody synthesis may be facilitated by inflammation. The persistence or reactivation of MV in SSPE may be related to other factors pertaining to the host or environment.

Tear eotaxin levels in giant papillary conjunctivitis associated with ocular prosthesis.

PURPOSE: To examine the role of eotaxin and eosinophil recruitment in the immunopathogenesis of ocular prosthesis-associated giant papillary conjunctivitis (GPC). METHODS: The tear eotaxin level was measured in 68 eyes with GPC, the fellow eyes of the GPC patients, and 22 normal subjects, using an ELISA method. Upper tarsal conjunctival specimens harvested from 18 patients with GPC were examined by light microscopy. RESULTS: There was no significant difference in tear eotaxin levels between patients with GPC and healthy subjects. In patients with chronic GPC, the tear eotaxin levels were significantly lower. These eyes also had decreased conjunctival cellularity and increased fibrosis in the substantia propria. Biopsy specimens showed infiltration of lymphocytes and mast cells, but no eosinophils were found. CONCLUSION: Eotaxin and eotaxin-mediated eosinophil recruitment do not seem to have a major role in the immunopathology of chronic GPC associated with an ocular prosthesis.

[Chemokine receptors: their role in human immunodeficiency virus (HIV) pathogenicity and resistance to HIV infections]. / Kemokin reseptörleri: insan immün yetmezlik virusu (HIV) patogenezinde ve HIV enfeksiyonuna dirençteki rolleri.

Chemokines are the chemoattractant cytokines which function briefly in inflammatory processes and also act as regulatory bridge molecules between innate and acquired immunity. Chemokines mediate their effects by binding to cell surface receptors that belong to the seven transmembrane domain superfamily of proteins, which are found mainly on the surface of leucocytes, macrophages and lymphocytes. Besides the functions in the immune system, certain chemokine receptors also function as co-receptors, in addition to CD4 molecule, for human immunodeficiency virus (HIV) entry into the target cells. Of these a beta-chemokine receptor CCR5 and an alpha chemokine receptor CXCR4 are the major co-receptors required for macrophage-tropic and T cell-tropic viruses, respectively. Genetic analysis has revealed the importance of chemokine receptor genes in the disease progression, and the identification of genetic polymorphisms such as alterations in the CCR5 gene that prevent surface expression, leads explaining why some people with CCR5 mutation are protected from HIV infection. Today it is accepted that chemokine gene deletion mutations and high production of chemokines are the host factors which take place in the resistance mechanisms of HIV-infected non- or slow-progressors. Depending on these data, recent studies have focused on chemokine receptor inhibitors and/or chemokine antagonists as the new therapeutic strategies that prevent HIV from interacting with receptors and block HIV infection. In this review, latest developments in chemokine receptor researches with a particular focus on their roles in HIV pathogenesis and resistance to HIV infection, have been discussed.

[Evaluation of western blot methods for serologic diagnosis of Helicobacter pylori infections]. / Helicobacter pylori enfeksiyonlarinin serolojik tanisinda western blot yönteminin degerlendirilmesi.

Recent studies have demonstrated that immunoblot method is more sensitive and specific than enzyme immunoassays (EIA) to diagnose Helicobacter pylori infections, and it also permits the detection of antibody profiles against different bacterial antigens including the virulence factors. The aim of this study was to evaluate the diagnostic value of Western Blot (WB) method in the serological diagnosis of H. pylori infections. For this purpose, H. pylori IgG and IgA antibodies have been searched qualitatively by a commercial WB test (Euroimmun GmbH, Germany), in the sera of 23 patients (9 female, 14 male) ages between 6-70 years old (13 children, 10 adults), who were diagnosed as H. pylori infection with the positive results of at least three of the conventional methods (culture and polymerase chain reaction of endoscopic biopsy specimens, 13C urea breath test, serum IgG-EIA methods). All of the patients (100%) were found positive by WB-IgG, and 9 (39%) were positive by WB-IgA tests. H.pylori IgG and IgA antibodies showed reactivity with the different combinations of p120 (CagA), p95 (VacA), p29 (UreA) and p66 (UreB) antigens. The number of positive samples for CagA-IgG, VacA-IgG, UreA-IgG, CagA-IgA and UreA-IgA were 19, 17, 21, 8 and 4, respectively, while there were no positive sample for VacA-IgA. The antigenic distribution did not show any difference between age and sex of the patients. In our study the sensitivities of WB-IgG and WB-IgA methods were estimated as 100% and 39%, respectively, which were in accordance with the studies in literature. As a result, WB-IgG method appears to be useful and reliable for the detection of antibody profiles to H. pylori antigens and virulence factors, rather than routine and screening purposes, however the diagnostic value of WB-IgA method is low. It was thought that the results of our preliminary study should be confirmed by other studies including larger patient populations and control groups, in our country.