Frequency and clinical impact of parvovirus B19 in systemic lupus erythematosus patients at Zagazig University Hospital

Abstract Background Systemic Lupus Erythematosus (SLE) is a chronic multisystem autoimmune disease whose complex etiology involves an interplay between hormonal, genetic and environmental factors. Viral infections, particularly Parvovirus B19 (B19V), are recognized as potential contributors to autoimmune pathogenesis and can induce transient autoimmune responses that mimic SLE flares. This study aimed to evaluate the prevalence of B19V infection via dual molecular and serological techniques and to determine its correlation with SLE disease activity scores and specific clinical features. Methodology A total of 44 adult patients diagnosed with SLE according to the updated Systemic Lupus International Collaborating Clinics (SLICC) criteria were enrolled, alongside an independent group of 44 age and sex matched healthy control subjects. Clinical assessment (medical history, clinical examination, routine laboratory investigations), B19V DNA detection via nested PCR and anti- B19V IgG and IgM antibodies evaluation via ELISA were performed. Results Rates of B19V DNA positivity (27.3% vs. 4.5%, P = 0.004) and B19V IgG positivity (47.7% vs. 18.2%; P = 0.003) were higher in SLE patients than in controls. Whereas B19V IgM positivity was similar between both groups (4.5% vs. 2.3%; P = 0.56). B19V DNA- positive SLE patients demonstrated lower median hemoglobin and complement levels (C3, C4), as well as higher inflammatory markers and autoantibody positivity rates compared to their levels in B19V DNA- negative patients. Additionally, a positive correlation was found between B19V DNA positivity and elevated Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) scores (Spearman’s rho = 0.542, P < 0.001). Conclusions Our findings demonstrate a significant association between B19V infection and SLE, tracking directly with higher clinical disease activity. A combined diagnostic workflow of both molecular and serological assays provides a more accurate assessment of viral status in clinical settings.