Antibody response and the clinical presentation of patients with COVID-19 in Croatia: the importance of a two-step testing approach.

According to anti-SARS-CoV-2 seroresponse in patients with COVID-19 from Croatia, we emphasised the issue of different serological tests and need for combining diagnostic methods for COVID-19 diagnosis. Anti-SARS-CoV-2 IgA and IgG ELISA and IgM/IgG immunochromatographic assay (ICA) were used for testing 60 sera from 21 patients (6 with severe, 10 moderate, and 5 with mild disease). The main clinical, demographic, and haemato-biochemical data were analysed. The most common symptoms were cough (95.2%), fever (90.5%), and fatigue and shortness of breath (42.9%). Pulmonary opacities showed 76.2% of patients. Within the first 7 days of illness, seropositivity for ELISA IgA and IgG was 42.9% and 7.1%, and for ICA IgM and IgG 25% and 10.7%, respectively. From day 8 after onset, ELISA IgA and IgG seropositivity was 90.6% and 68.8%, and for ICA IgM and IgG 84.4% and 75%, respectively. In general, sensitivity for ELISA IgA and IgG was 68.3% and 40%, and for ICA IgM and IgG 56.7% and 45.0%, respectively. The anti-SARS-CoV-2 antibody distributions by each method were statistically different (ICA IgM vs. IgG, p = 0.016; ELISA IgG vs. IgA, p < 0.001). Antibody response in COVID-19 varies and depends on the time the serum is taken, on the severity of disease, and on the type of test used. IgM and IgA antibodies as early-stage disease markers are comparable, although they cannot replace each other. Simultaneous IgM/IgG/IgA anti-SARS-CoV-2 antibody testing followed by the confirmation of positive findings with another test in a two-tier testing is recommended.

Chemokines CXCL10, CXCL11, and CXCL13 in acute disseminated encephalomyelitis, non-polio enterovirus aseptic meningitis, and neuroborreliosis: CXCL10 as initial discriminator in diagnostic algorithm?

We investigated potential diagnostic usefulness of serum and cerebrospinal fluid (CSF) concentrations of chemokines CXCL10, CXCL11, and CXCL13 in pediatric patients with acute disseminated encephalomyelitis (ADEM) (n = 23), non-polio enterovirus aseptic meningitis (NPEV AM) (n = 20), and neuroborreliosis (NB) (n = 21) and children with acute infectious diseases with neurological symptoms but with excluded neuroinfection/neuroinflammation (controls, n = 20). CSF levels of CXCL10 and CXCL11 were higher in patients with NPEV AM than those in other children, and CXCL10 levels showed a high discriminative potential (area under the receiver operating characteristic curve, ROC, 0.982) with high specificity and sensitivity (both 95%). CSF levels of CXCL13 were higher in NB patients than those in other children; however, discriminative potential (area under ROC curve 0.814) and diagnostic properties were moderate (sensitivity 67%, specificity 97%). Data suggest usefulness of chemokine quantification as a diagnostic aid in children with suspected ADEM, NPEV AM, or NB.

[HEPATITIS E IN CROATIA ­ GUIDELINES FOR DIAGNOSIS AND TREATMENT].

Hepatitis E is attributed great attention as an emerging worldwide-distributed zoonosis. The clinical presentation varies from severe fulminant in underdeveloped to milder forms of diagnostically unrecognized hepatitis cases in developed countries. Chronic hepatitis E is more often described in subjects with transplanted solid organs and HIV disease. The diagnosis of hepatitis E is established by determination of anti-HEV IgM and IgG with Western blot confirmation and detection of HEV RNA. In Croatia, the first case of indigenous disease caused by HEV genotype 3 (HEV-3) was detected in 2012. In this paper we present current knowledge on hepatitis E supplemented by own results obtained at the University Hospital for Infectious Diseases in Zagreb and guidelines for diagnosis and treatment of immunocompetent and immunocompromised individuals. In the period from 2011-2014, HEV was tested in 1107 patients, of whom 117 (10.6%) had anti-HEV antibodies. Acute HEV infection was diagnosed in 25 (2.3%) patients. Considering the prevalence of antibodies we can conclude that HEV diagnostics should be included in the diagnostic panel for patients with elevated aminotransferases.

[Recent developments in serologic and molecular diagnosis of hepatitis B and C]. / Novosti u seroloskoj i molekularnoj dijagnostici hepatitisa B i C.

The 2013 Update of the Croatian Guidelines for the Diagnosis and Treatment of Viral Hepatitis summarizes recent developments in the diagnosis of hepatitis B and C. Determination of HBsAg, anti-HBc and anti-HBs is the initial step in the diagnostic workup of acute and chronic hepatitis B. Other hepatitis B serologic markers should be analyzed in the second stage of the diagnostic workup in HBsAg and/or anti-HBc positive patients. A positive anti-HBc finding should be followed by HBV DNA quantification. HBsAg quantification is complimentary to the HBV DNA quantification and is used: (i) to differentiate between inactive HBsAg carriers and active chronic HBeAg-negative hepatitis B in patients with HBV DNA < 2000 IU/mL; and (ii) for treatment monitoring in patients with chronic hepatitis B receiving pegylated interferon-alpha. Real-time PCR remains the method of choice for detection and quantification of HBV DNA. The first step in HCV testing is determination of specific antibodies via screening assays, enzyme immunoassays or point-of-care assays. All persons with positive results of anti-HCV screening assays should be additionally tested for HCV RNA or presence of HCV viral capsid antigen. Confirmatory anti-HCV assays should be used as additional assays for confirmation of reactive results obtained by screening enzyme immunoassays in HCV RNA-negative persons only. Molecular assays with identical lower limit of detection (LLOD) and lower limit of quantification are recommended for monitoring of viral kinetics during chronic hepatitis C triple therapy. HCV resistance testing to protease inhibitors is not part of the recommended diagnostic monitoring of patients receiving triple therapy. HCV subtyping is currently not recommended as part of pretreatment diagnostic algorithm due to currently insufficient evidence on its clinical usefulness. IL-28 genotype is an important predictor of SVR in patients treated with a combination of interferon-alpha and ribavirin as well as in patients with HCV genotype 1 receiving triple therapy. IL-28B genotyping is recommended as part of pretreatment diagnostic workup in patients with chronic hepatitis C and is a particularly important parameter for recommending double versus triple therapy in treatment-naïve patients with chronic hepatitis C.

[Viralhepatitis. Croatian Consensus Statement 2013]. / Virusni hepatitis. Hrvatska konsenzus konferencija 2013.

Croatian Consensus Conferences on Viral Hepatitis took place in 2005 and 2009. Considering the numerous novel concepts on the epidemiology, diagnosis and management of viral hepatitis (chronic hepatitis C genotype 1 in particular) that have emerged in the past four years, a new Croatian Consensus Conference on Viral Hepatitis was held in Zagreb on February 28, 2013. The abridged text of the Croatian Consensus Conference on Viral Hepatitis 2013 presents the new concepts on the epidemiology of viral hepatitis, serologic and molecular diagnosis of viral hepatitis, determination of the IL-28 gene promoter polymorphism, fibrosis grading, algorithm for patient diagnostic follow up, treatment of chronic hepatitis C (genotypes 1-6) and hepatitis B, treatment of special populations (children, dialysis patients, transplanted patients, individuals with HIV/HCV co-infection), and therapy side effects.

Prevalence of HIV and sexually transmitted infections and patterns of recent HIV testing among men who have sex with men in Zagreb, Croatia.

OBJECTIVE: To determine the prevalence of HIV and other sexually transmitted infections (STIs) among men who have sex with men (MSM) in Zagreb, Croatia, and assess correlates of testing for HIV in the past 12 months. METHODS: The authors carried out a bio-behavioural survey using respondent-driven sampling (RDS) from September 2010 to February 2011. Participants completed a questionnaire and were asked to provide blood, urine, oropharyngeal and rectal swabs for the detection of infections. Data were analysed using RDS Analysis Tool 6.0.1 and STATA V.8.0. RESULTS: A total of 387 MSM were recruited at the University Hospital for Infectious Diseases. The age range of recruited men was 18-57 years. HIV prevalence was 2.8% (95% CI 1.1% to 5.1%) (3.6%, unadjusted), lower than that found in the first RDS survey carried out in 2006 (4.5%, 95% 2.2% to 7.3%) (4.9%, unadjusted). The seroprevalence of herpes virus type 2 was 5.9% (6.9, unadjusted) and that of syphilis measured by Treponema pallidum haemagglutination assay was 7.6% (6.7%, unadjusted). The authors found urethral and/or rectal infections with Chlamydia trachomatis in 7.2% (8.5%, unadjusted) of men and gonoccocal in 2.7% (2.1%, unadjusted). HIV testing in the past 12 months was reported by 32.7% (38.9%, unadjusted). In the multivariate analysis, significant correlates of recent HIV testing were having more than three partners in the past 12 months and the knowledge of HIV status of a regular partner. CONCLUSIONS: The results indicate that there might have not been a progression of an HIV and STI epidemic in the past 5 years among MSM in Croatia. Prevention should expand by providing better uptake of HIV and STI testing services, thus enabling timely treatment.

Serum levels of metalloproteinases and their inhibitors during infection with pathogens having integrin receptor-mediated cellular entry.

BACKGROUND: Matrix metalloproteinases (MMPs) are a family of proteolytic enzymes with numerous roles in the normal immune response to infection. However, excess MMP activity following infection may lead to immunopathological processes that cause tissue damage. Their activity in normal tissues is subject to tight control, which is regulated by its specific endogenous tissue inhibitors (TIMPs). It is known that MMPs bind to cell surface proteins (e.g. integrins) and that such interactions can have modulatory effects on MMP functionality. The objective of this study was to determine whether there are differences in MMP and TIMP production during the acute phase of infection with different pathogens that use ß-integrins as their receptors for cell entry. METHODS: We measured the total amounts of soluble MMP-2, MMP-9, TIMP-1, and TIMP-2 in the sera from patients infected with Dobrava virus (DOBV), Coxiella burnetii, or uropathogenic Escherichia coli. Statistical analyses were used to correlate MMP/TIMP serum levels with different clinical laboratory parameters. RESULTS: The results showed that both of the bacterial infections generally manifested the stronger effect on MMP production, while in contrast, viral infection introduced stronger changes to metalloproteinase inhibitors. MMPs and TIMPs were significantly correlated with some of the clinical laboratory parameters in both bacterial infections, but no correlations were found for DOBV infection. CONCLUSIONS: These findings suggest diverse mechanisms by which MMP activity could be implicated in the pathology of these 2 bacterial infections versus the viral DOBV infection, despite the type of their cellular entry receptors.

First case of Q fever endocarditis in Croatia and a short review.

We present a 70-year-old man from Dalmatia, Croatia, with a history of prolonged high fever diagnosed as Q fever endocarditis. As far as we know, this is the first case of chronic Q fever in Croatia. The treatment was started as for culture-negative endocarditis, but was without clinical response. After significantly high anti-phase I IgG plus IgA antibodies titers to Coxiella burnetii were shown, the initial treatment with doxycycline was changed and ciprofloxacin was started with good clinical response.

Prevalence of sexually transmitted infections among men who have sex with men in Zagreb, Croatia.

We used respondent-driven sampling among men who have sex with men (MSM) in Zagreb, Croatia in 2006 to investigate the prevalence of HIV, other sexually transmitted infections and sexual behaviours. We recruited 360 MSM. HIV infection was diagnosed in 4.5%. The seroprevalence of antibodies to viral pathogens was: herpes simplex virus type-2, 9.4%; hepatitis A, 14.2%; hepatitis C, 3.0%. Eighty percent of participants were susceptible to HBV infection (HBs antigen negative, and no antibodies to HBs and HBc antigen). Syphilis seroprevalence was 10.6%. Prevalence of Chlamydia and gonorrhoea was 9.0%, and 13.2%, respectively. Results indicate the need for interventions to diagnose, treat and prevent sexually transmitted infections among this population.

The occurrence of hemorrhagic fever with renal syndrome in southern parts of Bosnia and Herzegovina.

Bosnia and Herzegovina (B&H) has been known as an endemic region for hemorrhagic fever with renal syndrome (HFRS) for over 50 years. Multiple epidemics of this disease have been registered so far, especially in endemic parts of Central and Northeastern Bosnia, as well as the Sarajevo region. Seroepidemiological investigations demonstrate naturalization of Hantaviruses and their wide spread in B&H. However, there are no studies from the southern areas of B&H, and endemic foci of this disease are unknown. The aim of this study was to determine the distribution and serologic prevalence of Hantavirus infections by testing for specific IgG antibodies against hantaviruses in the population of Herzegovina. This study included two groups of participants. The target group consisted of 300 participants from exposed professional and population groups, and control group included 100 educators with lower exposure to HFRS. Identification of specific IgG antibodies against hantaviruses in 16 participants confirmed an initial assumption about the presence of Hantavirus infections in the region of interest. Seroprevalence of 5% was registered in the "exposed" and 1% in the "unexposed" group. Simultaneous circulation of Puumala (PUU) and Dobrava (DOB) viruses was discovered. The frequency of positive antibody results was higher in the population above 50 years of age, and three times more prevalent in men then at women. The highest proportion of exposed participants (80%) was registered in the municipalities which geographically belong to high or mountainous Herzegovina.

Seroprevalence of herpes simplex virus type 2 in adult HIV-infected patients and blood donors in Croatia.

The present study estimates herpes simplex virus type 2 (HSV-2) seroprevalence and evaluates its association with age, sex, human herpesvirus type 8 (HHV-8) and human immunodeficiency virus (HIV) among adults in Croatia. A cross-sectional survey included 166 HIV-infected patients and 219 blood donors. Antibodies against HSV-2 were determined by enzyme immunoassays based on gG2 recombinant glycoprotein. HSV-2 seroprevalence was 45.8% in HIV-infected patients and 8.7% in blood donors (p < 0.0001; OR 8.8; 95% CI 5.05-15.49). Independent predictors of HSV-2 seropositivity were HIV infection (OR 11.0; 95% CI 5.93-20.41), female gender (OR 2.28; 95% CI 1.22-4.26), older age (OR 3.93; 95% CI 2.74-7.11), and HHV-8 seropositivity (OR 2.72; 95% CI 1.09-6.75). Understanding the epidemiology of HSV-2 is a critical first step in designing interventions to decrease HSV-2 and HIV transmission. The association of HSV-2 with HIV infection and HHV-8 antibodies suggests a similar transmission route.

Evaluation of a commercial real-time PCR assay for quantitation of Epstein-Barr virus DNA in different groups of patients.

The aim of this study was to evaluate the performance of a molecular assay for quantitation of Epstein-Barr virus (EBV) DNA based on real-time PCR, and to determine EBV DNA levels in EDTA whole blood samples derived from different groups of patients. Following a manual DNA extraction protocol, real-time PCR was performed using the LightCycler EBV Quantification Kit, which demonstrated sufficient accuracy and linearity. Coefficients of variations were found to be between 6 and 42% and 5 and 34%, respectively, for inter-assay and intra-assay variations. In clinical specimens, EBV DNA was detected in all patients with acute EBV infection (n=34), in one of 25 adults with past EBV infection, in 16 out of 25 (64%) anti-HIV antibody positive persons, in 10 out of 25 (40%) solid organ transplant recipients, and in none of the 23 infants without history of EBV infection. When EBV DNA levels in positive specimens were compared between different groups, statistically significant differences were not found. The LightCycler EBV Quantification Kit was found to be useful for determination of EBV DNA levels in EDTA whole blood.

[Rash and purulent lymphadenitis in cat scratch disease]. / Osip i purulentni limfadenitis u bolesti macjeg ogreba.

We present a case of a cat-scratch disease (CSD) presenting with typical (primary lesion and regional lymphadenitis) and rare (purulent lymphadenitis and maculopapular rash) symptoms and positive epidemiological data. Laboratory blood test showed normal values for routine parameters, except for mild leukocytosis (L 12.4 x 10(9)), elevated erythrocyte sedimentation rate (SE 65/h) and moderately elevated asparta e-aminotransferase and alanine-aminotransferase values (AST/ALT 48/90), fibrinogen (5.3 g/L) and C-reactive protein (CRP 85 mg/L). Cytological analysis of lymph node content revealed granulomatous inflammation in the first sample, and purulent inflammation in the second sample. In paired serum samples, collected on the 15th and 29th day from the onset of disease, antibodies IgG (titre 4096/8192) and IgM (titre 80/40) to Bartonella henselae were detected by using an indirect immunofluorescence assay (IFA). Antibiotic therapy with azithromycin (1 x 500 mg per os/5 days) was administered. Purulent lymphadenitis and rash, although a rare clinical manifestation in CSD, are significant clinical findings in differentiating CSD from other febrile illnesses accompanied with rash and lymphadenitis.

Increased expression of CXCR3 and CCR5 on memory CD4+ T-cells migrating into the cerebrospinal fluid of patients with neuroborreliosis: the role of CXCL10 and CXCL11.

The aim of this study was to evaluate the contribution of chemokine receptor CXCR3 and the corresponding ligands CXCL10 and CXCL11 to the recruitment of peripheral blood (PB) memory CD4+ T-cells into the cerebrospinal fluid (CSF) of patients with acute neuroborreliosis. Percentages of memory CD45RO+CD4+ T-cells expressing CXCR3 and CCR5 were significantly enriched in the CSF compared to the PB. Concentrations of CXCL10 and CXCL11 in the CSF of neuroborreliosis patients were significantly higher compared with the corresponding serum samples. Our results suggest that CXCL10 and CXCL11 create a chemokine gradient between the CSF and serum and recruite CXCR3-expressing memory CD4+ T-cells into the CSF of neuroborreliosis patients and that CCR5 also plays a role in this process.