Mustafa Önel

Background/Objectives: Hepatitis B (HBV) and hepatitis C (HCV) coinfection leads to the progression of liver disease and results in clinically serious outcomes. Continuous monitoring of epidemiological data is crucial for managing the regional disease burden. This study investigates the current seroprevalence of HBV and HCV, the prevalence of coinfection, and the rates of active replication in Istanbul. Methods: This retrospective analysis included 7131 patients evaluated at the Infectious Diseases and Gastroenterohepatology clinics between 2021 and 2025. Initial serological screening for viral markers was performed using routine chemiluminescent immunoassays. Active viral replication was subsequently confirmed and quantified via real-time polymerase chain reaction (PCR). Results: Active HBV replication was significantly more frequent among patients in the Gastroenterohepatology clinic (20.47%) compared to those in Infectious Diseases (5.36%). Active HCV infections were rare in both departments (0.25% and 0.04%, respectively). Simultaneous HBV and HCV coinfection was detected in only 17 patients (0.24%). Demographic evaluation demonstrated that HBV marker positivity was more prevalent in male patients and individuals over 40 years of age. Conclusions: HBV seroprevalence remains substantially higher than HCV in this cohort. The high rate of active HBV replication in gastroenterohepatology settings indicates a concentrated burden of active disease in these specialized clinics. These distribution patterns emphasize the necessity of routine, targeted HBV screening for older male demographics to facilitate early clinical intervention.

Aims: Congenital cytomegalovirus (cCMV) infection is a major cause of prenatal morbidity, frequently associated with central nervous system (CNS) involvement. This study aimed to determine the frequency of CMV DNA in amniotic fluid (AF) samples obtained from pregnancies with high-risk ultrasound findings suggestive of prenatal CMV infection during the second trimester and to evaluate the associated prenatal findings.Methods: This retrospective study included 238 pregnant women who underwent amniocentesis between January 2023 and November 2025 due to high-risk ultrasound findings identified by experienced perinatologists. CMV DNA in AF samples was detected using Real-Time PCR (RT-PCR). Maternal CMV IgG and IgM serological results were obtained from patient records. Prenatal ultrasound findings, serological data, and molecular test results were analyzed statistically. Results: CMV DNA was detected in 10 of 238 AF samples (4.20%; 95% confidence interval: 1.7-6.8%). In cases with CMV DNA positivity, prenatal ultrasound findings predominantly involved CNS anomalies (80%). CMV IgG positivity was observed in all CMV DNA-positive cases, while CMV IgM positivity was not detected in any patient. Conclusion: The strong association between CNS-predominant ultrasound anomalies and CMV DNA positivity underscores the diagnostic value of CMV DNA PCR testing in AF samples for prenatal CMV infection. These findings support the use of molecular diagnostic methods alongside ultrasonographic evaluation, as maternal serological screening alone may be insufficient for accurate prenatal CMV diagnosis.

Background/Objectives: Patients with rheumatic diseases have an increased burden of infection owing to biological disease-modifying antirheumatic drug (bDMARD) therapy. Therefore, vaccination is crucial for the prevention of infection in these patients. In this case–control study, we aimed to evaluate vaccine response to hepatitis B, pneumococcus, and measles using antibody titers in patients undergoing biological therapy. Methods: This study included 16 patients aged 5–18 years of age who received bDMARD treatment and 20 healthy controls. Serum samples of the patients were collected at baseline and subsequently on the 3rd and 6th months after bDMARD therapy, and IgG antibodies against pneumococcal capsular polysaccharide antigen (PCP), measles, and hepatitis B were measured. Results: There were no statistically significant differences in mean anti-HBsAg, anti-PCP, and anti-measles antibody titers between the study and control groups. The percentages of patients with anti-HbsAg, anti-PCP, and anti-measles protective antibodies were 68.8% (n = 11/16), 100% (n = 16/16), and 56.25% (n = 9/16), respectively. There were no statistically significant differences in the mean antibody titers at baseline and 3rd month. Only the anti-measles IgG titer level decreased below 200 (mIU/mL) in one patient in the 3rd month and in two patients in the 6th month. Conclusions: Patients with low or declining hepatitis B and measles antibody titers before or during bDMARD treatment may require close monitoring to ensure adequate protection against vaccine-preventable diseases. Regular screening and follow-up are essential in this patient population.

(1) Background: This study investigated the presence of human papillomavirus (HPV), HPV genotypes, Epstein–Barr virus (EBV), cytomegalovirus (CMV) and herpes simplex virus (HSV) in patients with Head and Neck Cancer (HNC) at both molecular and serological levels. (2) Methods Fifty patients with histopathologically confirmed HNC who were admitted to the Department of Otorhinolaryngology, Istanbul Faculty of Medicine. Viral DNA was detected using quantitative real-time PCR, and serological IgM and IgG antibodies were analyzed using the CMIA method; (3) Results: In blood samples, CMV and HSV DNA were not detected, whereas EBV DNA was identified in 2% and HPV DNA in 4% of patients. In tumor tissues, CMV DNA was detected in 8%, EBV DNA in 10%, and HPV DNA in 6%; HSV DNA is 6%. HPV genotypes 18, 45, and 69 were found in tissue samples. Serologically, IgG positivity for CMV, EBV, and HSV-1 exceeded 90%, whereas IgM positivity was low and not statistically significant; (4) Conclusions: HPV, EBV, and CMV DNA were detected at low frequencies in patients with HNC, while HSV DNA was absent. These findings underline the need for larger multi-center studies and support the consideration of routine viral screening, particularly for HPV, in specific tumor subtypes.

Aims: This study retrospectively evaluates the serological (CMV IgM and IgG) and molecular (CMV DNA PCR) test results of patients admitted to İstanbul Faculty of Medicine Hospital between 2021 and 2023 due to suspected cytomegalovirus (CMV) infection. The aim is to assess the diagnostic value of combining serological and molecular methods and to analyze CMV positivity across age and gender groups. Methods: This cross-sectional observational study included 1.649 patients who underwent CMV testing (CMV IgM, CMV IgG, and/or CMV DNA PCR) at the Medical Microbiology Laboratory of İstanbul Faculty of Medicine between January 1, 2021, and December 31, 2023. Serological tests were performed using ELISA (Vircell, Spain), and CMV DNA was quantified using real time PCR (QIAsymphony/Artus CMV QS-RGQ and cobas® 6800). Data were anonymized and analyzed statistically using SPSS v26.0. Mann-Whitney U, Chi-square, McNemar, and ROC tests were applied; p0.05), CMV DNA positivity varied significantly across age groups (p

This study aimed to investigate prolonged severe acute respiratory syndrome coronavirus-2 polymerase chain reaction (PCR) positivity in hospitalized COVID-19 patients and evaluate the diagnostic performance of rapid antigen tests (RAgT) compared to real-time reverse transcription-PCR (RT-PCR). A prospective single-center study included 82 patients with prolonged PCR positivity (≥28 days). Serial RT-PCR and RAgT were performed at days 7 to 10, 14 to 20, and 28 to 30 post-diagnosis. Clinical data, comorbidities, and laboratory parameters (inflammatory markers, hematological, and biochemical profiles) were analyzed. Statistical analyses included sensitivity, specificity, Cohen Kappa, and receiver operating characteristic curve assessment. RAgT demonstrated 100% sensitivity and 74% specificity relative to RT-PCR, with strong agreement (Cohen κ = 0.803, P* < .001). Inflammatory markers were elevated: C-reactive protein (median 3.55 mg/L), ferritin (510 µg/L), and D-dimer (1400 ng/mL). Comorbidities were present in 62% of patients, primarily hypertension (17%) and diabetes mellitus (15%). Female patients exhibited higher inflammatory markers (C-reactive protein, fibrinogen, and lactate dehydrogenase) and anemia prevalence. Receiver operating characteristic analysis revealed excellent discriminative performance (area under the curve = 0.99). RAgT showed high sensitivity in detecting severe acute respiratory syndrome coronavirus-2 among patients with prolonged PCR positivity, suggesting potential utility in differentiating active infection from residual viral RNA. Persistent PCR positivity may correlate with noninfectious viral shedding, and RAgT could complement RT-PCR in clinical decision-making, particularly in resource-limited settings. Further multicenter studies are needed to validate these findings and assess the impact of viral variants.

Objective: This study aimed to retrospectively investigate the prevalence of cytomegalovirus (CMV), Epstein-Barr virus (EBV), human papillomavirus (HPV), and herpes simplex virus (HSV) in patients with head and neck cancer, in relation to age, sex, tumor type, and risk factors, at both molecular and serological levels. Materials and Methods: Data from 50 patients diagnosed histopathologically with head and neck cancer who were admitted to the Department of Otorhinolaryngology, Istanbul Faculty of Medicine, between April 2023 and April 2024 were reviewed. At the time of diagnosis, venous blood and tumor biopsy tissue were collected from all cases. CMV, EBV, HPV, and HSV DNA were investigated in both blood and biopsy samples using quantitative real-time PCR. Serologically, IgM and IgG levels were measured using the CMIA method. The data were analyzed along with demographic and clinical parameters. Results: In blood samples, CMV and HSV DNA were not detected, while EBV DNA was found to be positive in 2% and HPV DNA in 4% of the cases. In biopsy tissues, CMV DNA was detected in 8%, EBV DNA in 10%, and HPV DNA in 6% of the samples; HSV DNA was also not detected in tissue samples. HPV DNA positivity showed a statistically significant variation according to tumor type and was more frequently detected in the subtypes of tongue SCC and retromolar SCC (p = 0.005). In serological evaluation, IgG positivity for CMV, EBV, and HSV-1 was above 90%, whereas IgM positivity for all viruses was low and not statistically significant. Conclusion: Among patients with head and neck cancer, the overall positivity rates for HPV, EBV, and CMV DNA were low, and HSV DNA was not detected. The higher prevalence of HPV in specific tumor subtypes suggests a selective role of this virus in head and neck cancers. These findings highlight that the viral etiology of head and neck cancers may vary depending on tumor subtype and individual factors, emphasizing the importance of regional epidemiological data.

The aim of the study was to determine the prevalence rates of respiratory pathogens using syndromic tests and also to show which respiratory viruses were detected in suspected cases, especially during and after the pandemic period. A total of 1984 different respiratory tract samples from various departments were included and studied with the QIAstat-Dx device in 2021–2023. The samples were studied with the QIAstat-Dx1 Respiratory SARS-CoV-2 Panel. The kit used was a fully automated, multiplex syndromic test that detected SARS-CoV-2 and 21 other respiratory tract pathogens. As a result of the study, the prevalence of Rhinovirus/Enterovirus (RV/EV) (18.59%), RV/EV-SARS-CoV-2 (42.74%), SARS-CoV-2 (5.04%), and Influenza A Virus (IAV) (5.59%) agents was found to be higher than other agents during the period investigated. Among the 1984 patients examined, 959 (48.33%) had a single viral agent, 156 (7.86%) had double coinfection, 11 (0.55%) had triple coinfection and 1 patient had quadruple coinfection. Nearly half of the patients had a straightforward infection, which helps clinicians in directing specific treatment methods. The study results demonstrate that during the pandemic period, the detection of respiratory pathogens such as SARS-CoV-2 and RV/EV was not only critical for accurate diagnosis but also served as an important indicator of the broader epidemiological trends in respiratory infections. The seasonal distribution showed that while RV/EV was frequently present, its coinfection with SARS-CoV-2 was notably observed only in the first trimester. In light of our findings showing high rates of SARS-CoV-2 and RV/EV detection, along with diverse patterns of coinfection in clinical samples, such comprehensive testing not only assists in rapid diagnosis but also informs public health strategies by reflecting the evolving landscape of respiratory infections in the pandemic and post-pandemic era.

Parvovirus B19 is a very common infection, especially in school-age children, with its rapid spread. In the present study, Parvovirus B19 infection was detected in frequently ill nursery children. The present study aimed to determine the seroprevalence value, to determine whether there is an active infection and to determine to what extent it affects the relevant immune system parameters, to determine whether the obtained data will contribute to the epidemiology of childhood Parvovirus B19 infections in our country and also, to determine whether it is a reason for children to become ill frequently. Parvovirus B19 DNA test results of 112 children aged 2–6 years who were grouped as frequently ill and infrequently ill and who went to nursery and kindergarten were examined quantitatively with the Real-Time PCR Method. Parvovirus B19 IgG and Parvovirus B19 IgM antibody presence was investigated with the ELISA Method. Flow Lymphocyte subgroups were analyzed with the Cytometry Method. Among the 112 patients who were included in the study, 105 (93.7%) Parvovirus B19 DNA results were negative and 7 (6.3%) were positive. Parvovirus B19 IgG test results were negative in 108 (96.4%) patients and positive in 4 (3.6%). When the Parvovirus B19 IgM results were evaluated, 109 (97.3%) were determined as negative and 3 (2.7%) positive. Natural Killer Cells (NK) from patients with positive Parvovirus B19 DNA, Parvovirus B19 IgG, and IgM were detected outside the normal limit value ranges in CD25, CD19, HLA DR, CD3, CD45RO, and CD8 values. No significant relationships were detected between frequent illness and Parvovirus B19 infection, the infection did not significantly affect the immunodeficiency parameters, and although it is already known that Parvovirus B19 infection peaks every 3–4 years, the study did not coincide with this period of Parvovirus B19 infection.

Aim: Respiratory viruses significantly impact public health, contributing to high morbidity and mortality rates in both children and adults. This study evaluates the distribution and incidence of respiratory tract viruses in our hospital from 2019 to 2022, focusing on changes post-COVID-19 pandemic. Material and Methods: Utilizing molecular methods, we analyzed nasopharyngeal swabs with the FTD Respiratory Pathogens 21 kit and the QIAStat Dx Respiratory Panel kit at Istanbul Faculty of Medicine. A total of 1186 viruses were detected in 2488 samples (47.6% of the total) examined with the FTD Respiratory Pathogens 21 kit between 2019 and 2022. Results: It was determined that the detection rates were 52.8% in 2019, 44.3% in 2020, 50.0% in 2021, and 40.0% in 2022. Notable changes in prevalence were observed for pandemic influenza A (IAV-H1N1pdm2009), parainfluenza virus (PIV)-3, rhinovirus (RV), and respiratory syncytial virus (RSV)-A/B (p < 0.05). RV consistently showed the highest detection rates across all years (17.6% to 7.9%). Additionally, 1276 viruses were detected in 1496 samples using the QIAStat DX kit, with 91.3% positivity in 2021 and 78.6% in 2022, highlighting the kit’s effectiveness in rapid diagnosis. Conclusions: This study enhances understanding of respiratory virus epidemiology during and after the pandemic, emphasizing the need for ongoing surveillance and strategic public health measures to address the evolving landscape of respiratory infections.