Possible immunosuppressive effects of drug exposure and environmental and nutritional effects on infection and vaccination.

A variety of drugs which are not primarily considered to be immunosuppressive agents have been described to modulate the humoral and cellular immune response in humans or animals. Thereby they may have an influence on the effectiveness and possible side effects of vaccines. This mini review lists some of the different substance classes and also some of endogeneous, infectious, nutritional, and environmental influences with suspected capability to interfere with immunizations. Studies in most cases focused on substances with known immunosuppressive functions, but there is growing evidence for immunomodulatory effects also of commonly used drugs with wide distribution. In particular combinations of those antiproliferative and antiphlogistic side effects of different substance classes have not been studied in detail but may substantially interfere with the development of a functional humoral and cellular immune response. The drugs of importance include antipyretics, anticoagulants, tranquilizers, and substances influencing lipid metabolism but also commonly used drugs of abuse like alcohol or cannabinoids. Additional substances of environmental, nutritional, or microbiological origin may also play a role but their combinatory/synergistic effects have been disregarded so far due to the lack of systematic data and the complex study designs necessary to elucidate those complex epidemiologic questions.

Nail psoriasis masqueraded by secondary infection with Rhodotorula mucilaginosa.

A 38-year-old man presented with whitish nail changes on all fingers as the sole symptom. The condition had developed within a few days and led to dystrophy of the proximal part of the nail plates. As microscopic examination of nail scrapings demonstrated budding hyphae and the patient working as a teacher reported frequent use of a wet sponge, antifungal therapy was initiated. Subsequent cultures and molecular typing identified Rhodotorula mucilaginosa (formerly R. rubra). This environmental yeast was repeatedly isolated despite of therapy with itraconazole. As no improvement was achieved and testing of the biological activity of the fungus revealed only marginal keratolytic activity, it was considered as a coloniser of a destructed nail matrix. Finally, a biopsy of the nail bed confirmed the diagnosis of nail psoriasis, which rapidly responded to treatment with acitretin and topical calcipotriol/betamethasone cream. Fungal growth in destructed nails masqueraded the underlying disease and may have triggered the psoriatic nail reaction.

Comparison of hepatitis C virus subtyping by ns5b sequencing with 5'utr based methods.

AIM: We compared Hepatitis C virus (HCV) genotyping by direct sequencing of the non-structural 5b region (NS5b) and a commercial PCR/hybridization method based on the conserved 5´-untranslated region (5'UTR). METHODS: One hundred twenty HCV containing plasma samples were analyzed by NS5b sequencing with focus on samples with undetermined results or 1b subtype identification in the used combination of Cobas® AmpliPrep/Cobas® TaqMan96® PCR and subsequent Versant® HCV Genotype 2.0 Assay (LiPA). RESULTS: There was 100% concordance between the two methods for genotyping but only 83% for subtyping. Seventeen samples were designated 1b by hybridization but subtype 1a by NS5b sequencing. This is a general 5'UTR problem as the discordant results were additionally confirmed by 5'UTR sequencing. Thus our routine combination not only misclassified 38.6% of subtype 1a isolates as 1b but in contrast to NS5b sequencing was unable to discriminate between subtypes 2a/c, or 4a/c/d and also failed on a newly described subtype (10a/3k). [corrected]. CONCLUSIONS: [corrected] The applied 5'UTR methods allow the rapid determination of HCV genotypes but failed to correctly identify the subtype in many samples. This has implications for epidemiological studies or forensic evaluation of chains of infection and NS5b sequencing therefore is our method of choice under those circumstances.

Immunosurveillance for Mycobacterium tuberculosis of health care personnel in a third level care hospital.

BACKGROUND: Health care workers are at risk for Mycobacterium tuberculosis (MTB) infection. OBJECTIVES: To perform an occupational health survey among 621 employees of a 800-bed third level care hospital covered by MTB surveillance. METHODS: Statistical analysis was applied to results from tuberculin skin test (TST), QuantiFERON - TB Gold in tube assay (QFT), PPD-ELISA for serum antibodies, and occupational or vaccine data. RESULTS: 29.1% of subjects were TST positive, 18.5% were QFT positive. In 23% of subjects no correlation between these tests was found, presumably linked to BCG-vaccination, since TST positivity was 4 times higher among vaccinated subjects, whereas both tests correlated well in unvaccinated subjects. QFT values above 2 IU/ml were significantly associated with positive TST and age over 40 years. Working in MTB risk level 4 was significantly associated with QFT, TST and PPD-antibody levels, suggesting booster effects by repeated exposure. No clear correlation was observed with medical specializations but significantly higher QFTpositivity was found in subjects not assigned to the classical medical professions and originating from MTB high risk areas. CONCLUSIONS: These results shift the focus on maintenance personnel, who mostly worked in MTB risk level 2 areas. The less positive QFT results in vaccinated subjects highlight QFT's advantage as a screening tool and argue for a protective effect of the BCG-vaccine, although percentages of vaccinated persons varied largely between different medical professions. Interestingly, the percentage of QFT positive persons was lower among subjects reporting MTB exposure than those who were not aware of exposure events.

Phylogenetic evidence for a recent spread of two populations of human enterovirus 71 in European countries.

Human enterovirus 71 (EV-71) is a cause of seasonal epidemics of hand, foot and mouth disease, and of less common but severe neurological manifestations. Uncertainty persists regarding the circulation of virus populations in several geographical areas and the timescale of their dissemination. We determined EV-71 sequences at loci 1D (VP1 capsid protein) and 3CD (non-structural proteins) in 86 strains recovered in Austria, France and Germany and performed an evolutionary genetic study of extant virus populations. Phylogenetic analyses positioned 78 of the 86 sequences within two clades among subgenogroups C1 and C2. A minor sequence cluster was assigned to subgenogroup C4. Analyses incorporating the available sequences estimated the substitution rate in genogroup C at 3.66 x 10(-3) and 4.46 x 10(-3) substitutions per site year(-1) for loci 1D and 3CD, respectively, assuming a relaxed molecular-clock model for sequence evolution. Most of the 'European' strains belonged to clades C1b and C2b, which originated in 1994 [95 % confidence interval (CI), 1992.7-1995.8] and 2002 (95 % CI, 2001.6-2003.8), respectively. Estimates of divergence times for locus 3CD were consistent with those measured for locus 1D. Intertwining between clades representing EV-71 subgenogroups and clades corresponding to other enterovirus types (notably early coxsackievirus A prototype strains) in the 3CD phylogeny is highly indicative of ancestral recombination events. Incongruent phylogenetic patterns estimated for loci 1D and 3CD show that a single tree cannot model the epidemic history of circulating EV-71 populations. The evolutionary timescale of genogroup C estimated for both loci was measured only in decades, indicating recent dissemination.

Natural zoonotic infections of two marmosets and one domestic rabbit with herpes simplex virus type 1 did not reveal a correlation with a certain gG-, gI- or gE genotype.

Infections with herpes simplex virus type 1 (HSV-1) are not restricted to humans but infrequently may be transmitted to certain animal species, in some cases resulting in severe disease, including encephalitis and death. Recent studies demonstrate that humanderived HSV-1 field isolates can be typed according to their gG- gIand gE gene sequences. We investigated whether HSV-1 infections of animals were predominantly caused by a certain genotype. Isolates derived from two marmosets and one domestic rabbit, however, revealed different genotypes. Despite the very limited number of investigated animal-derived HSV-1 strains, this result does not point towards the existence of certain HSV-1 genotypes with a higher potential of being transmitted to animals.

"Recreational" drug abuse associated with failure to mount a proper antibody response after a generalised orthopoxvirus infection.

Infections with orthopoxviruses usually lead to cross-protection among all species of the family. This has been a prerequisite for successful eradication of smallpox. Here we report the rare case of a 17-year-old male, who survived a generalised cowpox virus infection of unusual severity but surprisingly did not show a proper seroconversion. Only a very weak antibody production was observed in early and late serum samples, which initially appeared to be cowpox virus specific in immunofluorescence. No neutralising antibodies were detected and in Western blotting antibody specificity was restricted to the orthopoxvirus H3L protein only. The patient had been hospitalised for alcohol and cannabis intoxication 2 months prior to the orthopoxvirus infection and high levels of cannabinoids have been found repeatedly in the urine and upon one occasion also benzodiazepines. As these substances are known to interfere with antibody production and no immunodeficiencies were detected, drug-induced immunosuppression can be suspected as the most likely cause. Therefore a possible link between "soft" drug use and sufficient immunosuppression to warrant alterations in vaccine policies using live virus vaccines like smallpox vaccine should be further studied.

Prevalence of respiratory viruses, including newly identified viruses, in hospitalised children in Austria.

The aim of this epidemiological study was to determine the prevalence of respiratory viruses, including new viruses, in hospitalised children in Austria. Two hundred fourteen nasopharyngeal samples from hospitalised children were tested for the presence of viruses using cell culture and PCR and/or viral antigen assays. The results revealed a parainfluenza virus 1 (PIV1) outbreak that ended right before the onset of the influenza season, with nearly no overlapping, moderate respiratory syncytial virus (RSV) activity, and only a few adenoviruses. Human metapneumovirus (hMPV) was present in 14.5% of the total samples but was detected in combination with other viruses in only five cases: with PIV1 in three cases and with RSV in two cases. There were no cases of dual infection with hMPV and flu or adenovirus. This suggests that hMPV alone is a leading cause of hospitalisation in children under 1 year of age. Interestingly, hMPV, in contrast to RSV, coincided with PIV1 but was absent during the community outbreak of the flu. Samples were also tested for Mimiviridae, a group of newly described DNA viruses that are similar to Legionella spp., replicate in water amoebae, and also have been found in alveolar cells. However, mimivirus was detected neither in respiratory samples nor in amoebae-containing water samples, indicating that this particular type of virus is either not abundant or does not contribute to paediatric respiratory illnesses.

Visceral leishmaniasis in an AIDS patient on successful antiretroviral therapy: failure of parasite eradication despite increase in CD4+ T-cell count but low CD8+ T-cell count.

An unusual cutaneous relapse of visceral leishmaniasis (initially mistaken for eruptive histiocytomas) was seen in an AIDS patient despite good virological and CD4+ T-cell responses to highly active antiretroviral therapy. Splenectomy and the patient's low CD8+ T-cell count are discussed as possible causes of failed disease control.

Induction of recombinant gene expression in stably transfected cell lines using attenuated vaccinia virus MVA expressing T7 RNA polymerase with a nuclear localisation signal.

There are major drawbacks using vaccinia virus (VV) expressing T7 polymerase for eukaryotic expression. VV is infectious for humans and due to cytosolic replication of Poxviridae, transient transfection of T7 promoter containing plasmids is necessary, which varies in efficiency. Several improvements have been introduced to this system to enhance expression of herpes viral glycoproteins. Stably transfected cell lines were generated with an EBV-based episomal plasmid vector which can be pushed to increasing copy numbers under selective pressure. The avirulent vaccine MVA strain was adopted to generate a safe laboratory vector for inserting the bacteriophage T7 RNA polymerase gene with (+) or without (-) a nuclear localisation signal. Constructs were designed for recombination into the VV haemagglutinin gene as recombinants could not be isolated successfully when inserting into the MVA thymidine kinase locus. Both T7 MVA recombinants induced foreign protein expression in transiently transfected cells but only the T7-/+ MVA induced target protein expression in stably transfected cells. The level of protein expression by this induction mechanism was comparable to, or superior to levels obtained with VV recombinants expressing the gene under control of the VV 11 k IE promoter. The results suggests that the T7+ MVA virus can be used to induce gene expression in stable recombinant cell lines and offers an attractive and safe alternative to other inducible eucaryotic expression systems.

Use of apathogenic vaccinia virus MVA expressing EHV-1 gC as basis of a combined recombinant MVA/DNA vaccination scheme.

The nonreplicating chicken adapted vaccinia virus strain MVA was used in a combined vaccine scheme. Using the equine herpesvirus type 1 (EHV-1) encoded complement-receptor glycoprotein C as antigen, only poor antibody response was induced by exclusive vaccination with DNA plasmids. The administration of recombinant MVA followed by plasmid immunization elicited both humoral and cellular immune responses in hamster comparable to EHV-1 full virus vaccines. Our results indicate that recombinant constructs based on MVA represent a safe and efficient way to overcome problems of poor immunogenicity of certain antigens upon intramuscular DNA vaccination, thus replacing sophisticated adjuvants or application methods, which are not readily applicable in routine practice.

Epstein-Barr virus-associated persistent polyclonal B-cell lymphocytosis with a distinct 69-base pair deletion in the LMP1 oncogene.

Epstein-Barr virus (EBV) genomes have been detected in peripheral blood lymphocytes (PBL) of patients with persistent polyclonal B-cell lymphocytosis (PPBL). This is consistent with the hypothesis that latent EBV infection is involved in the pathogenesis of this disorder. Two EBV-encoded proteins expressed in viral latency are the latent membrane proteins 1 and 2A (LMP1 and LMP2A). We have studied the LMP1 oncogene and the LMP2A gene in a female patient with PPBL and her five siblings. A cell line derived from peripheral blood lymphocytes (PBL) of the patient was also analyzed. A distinct 69-base pair deletion was identified within the carboxy terminal NF-kappa B activation domain of the LMP1 oncogene in PBL of the patient and in the cell line, whereas none of the siblings harbored this deletion. The tyrosine-signaling motif and the HLA A2.1 epitope of the LMP2A gene were wild type in the patient and all siblings. The presence of a 69-base pair deletion variant of the LMP1 oncogene within the lymphocytes of a PPBL patient but absence of this deletion variant in the unaffected siblings suggests a direct implication of altered LMP1 oncoprotein-dependent function in the pathogenesis of PPBL.

Influence of viral infection on expression of cell surface antigens in human retinal pigment epithelial cells.

BACKGROUND: Subacute viral infection is known to change the phenotype of infected cells, thereby causing immune-mediated tissue damage. The aim of this study was to investigate the expression of different cell surface molecules on human retinal pigment epithelial cells (RPEC) following viral infection, with special emphasis on those having immune-regulatory functions. METHODS: Cultured RPEC were infected with cytomegalovirus (CMV), coxsackie-virus B3 (CVB) or herpes simplex virus type I (HSV). Double-staining fluorescence technique was used for visualization of virus infection and cell surface markers in the same cells by laser microscopy. RESULTS: CMV downregulated MHC class I antigens on RPEC, whereas CVB and HSV did not alter MHC class I antigen expression. No induction of class II antigens was observed in RPEC infected with CVB, HSV or CMV. The intercellular adhesion molecule ICAM-1 (CD54) was strongly expressed in uninfected RPEC, and a slight increase was observed after virus infection. Vascular cell adhesion molecule 1 (VCAM-1) was expressed in low amounts in both uninfected and infected RPEC. No expression of intercellular adhesion molecule 2 (ICAM-2), E-selectin ELAM-1 or lymphocyte-function-associated antigen 1 (LFA-1) was observed on RPEC before or after virus infection. CONCLUSION: Downmodulation of immune-regulating cell surface antigens has been suggested to provide a means of long-term survival of viruses in the infected cell, favoring establishment of persistent infection. Our observation in cultured human RPEC indicates that this mechanism might indeed contribute to the development of disease affecting retinal tissue.

Pathogenesis of chronic Epstein-Barr virus infection: detection of a virus strain with a high rate of lytic replication.

In rare cases Epstein-Barr virus (EBV) leads to chronic active infection (CAEBV) which is characterized by persistant symptoms of infectious mononucleosis. Previously we described a case of persisting polyclonal B-cell lymphocytosis (PPBL) that was associated with CAEBV. Using reverse transcription and polymerase chain reaction we showed that in late passages of a spontaneous cell line, SM, latent EB viral genes such as EBNA1, EBNA2, EBNA3A/3B/ 3C, LMP1 and LMP2A were active. The master gene of the lytic cycle, BZLF1, was silent. This indicated that there was no general defect in immortalization and establishing latency by this CAEBV isolate SM. We obtained virus from the standard immortalizing strain B95-8 and the CAEBV strain SM from latently infected LCL quantified the number of virus particles by competitive PCR and demonstrated that the impaired capacity to immortalize umbilical cord blood lymphocytes was a virus strain-specific property, and was not due to an incapability to infect purified CD19+ B lymphocytes. Transcription of latency- and immortalization-associated genes such as EBNA1, EBNA2 and LMP2A was reduced, in contrast to a strongly enhanced activity of the master gene of the lytic cycle, BZLF1. A scenario for an antagonistic regulation of lytic and latent cycle genes is presented and a role for the pathogenesis of CAEBV is discussed.

Susceptibility of human retinal pigment epithelial cells to different viruses.

BACKGROUND: Different viruses have been reported to be involved in retinal diseases in animal systems. In humans, herpes simplex virus and cytomegalovirus have been found to cause retinal disease. Most of the studied viruses are neurotropic. In this study, the in vitro susceptibility of human retinal pigment epithelial cells (RPEC) to representative members of different groups of human pathogenic viruses was investigated. METHODS: Early cultures of RPE C - after two or three passages - were infected with the following viruses: herpes simplex virus (HSV) type 1, human herpesvirus 6 (HHV-6), Epstein-Barr virus (EBV), cytomegalovirus (CMV), adenovirus types 1 and 7, measles virus, parainfluenza virus and coxsackie virus B3. RESULTS: Cultures of RPE C could be infected with neurotropic viruses like HSV or measles virus as well as with typical respiratory viruses like parainfluenza or adenoviruses. Coxsackievirus, an enterovirus, replicated as well as human CMV, whereas EBV and HHV-6, two lymphotropic viruses, failed to infect RPE. CONCLUSION: These findings suggest that a variety of viruses, including those causing rather common illnesses, might be capable of inducing retinal lesions under certain circumstances due to haematogenous spread during the course of viraemia.

Chronic active Epstein-Barr virus disease in a case of persistent polyclonal B-cell lymphocytosis.

Persistent polyclonal B-cell lymphocytosis (PPBL) is a rare haematological disorder. It is characterized by activated and morphologically atypical B lymphocytes and polyclonal IgM production and has been associated with female sex, cigarette smoking, and HLA-DR7 expression. We report a case of PPBL with intermitting symptoms compatible with a chronic fatigue syndrome, recurrent erythema nodosum and multiforme. Serological findings suggested a chronic active Epstein-Barr virus (EBV) infection. Messenger RNA of EBV immediate early gene transactivation BZLF1 was detected in peripheral blood lymphocytes by reverse transcriptase PCR indicating a persistent replication of the virus. Over 2 years of observation we detected varying numbers of atypical lymphocytes. These cells hybridized with a probe specific for the EBV internal repeat region (BamHI W) which indicates a productive infection. Of interest, no reaction was observed with a probe specific for the latency-associated small RNAs (EBERs). The immunological phenotype of the polyclonal B cells was similar to B-cell lines immortalized by EBV in vitro, expressing a number of activation molecules (CD23, CD25, CD54) and the bcl-2 protein. In summary, our findings suggest that persistent EBV replication might be crucial in the development of lymphoproliferative disorders such as PPBL.

Role of Epstein-Barr virus and soluble CD21 in persistent polyclonal B-cell lymphocytosis.

The expression of EBV proteins and immunological properties were studied in the first stable cell line (SM) established from a patient presenting with persistent polyclonal B-cell lymphocytosis (PPBL). SM cells which represent a small population of EBV-positive atypical cells found in the peripheral blood of the patient express the KI-1 antigen (CD30) as well as the proto-oncogene bcl-2 product and cell surface markers of mature activated B lymphocytes. The cells harbour an EBV subtype A genome and contain EBNA2 protein. This argues against a transformation-incompetent virus as the main cause of the chronic active EBV infection observed in our patient. Latent membrane protein (LMP1) was weakly expressed and found predominantly in a perinuclear localization, a location which could lead to decreased immunogenicity in vivo. Similar to the EBV-transformed marmoset cell line B95-8, SM cells were in part productively infected as transcription of the immediate early gene BZLF1 could be shown and in some cells high levels of EBV-genome were detected by in situ hybridization with a BamH1 W-probe. Comparable to the atypical cells in the peripheral blood of the patient. EBV small RNAs were not detected with EBER-specific probes. Of interest, we noticed a markedly increased production of soluble CD21 (sCD21) antigen by SM cells as compared to LCL-type Burkitt's lymphoma cell lines. This could explain the elevated sCD21 levels observed in the serum of our PPBL patient and confirms our previous findings in patients with acute EBV infection. It also suggests a possible role of sCD21 in EBV-mediated regulation of the immune response and provides a possible explanation for the dysregulation of the humoral immune system observed in PPBl patients.