BK Virus Detection by Real-Time Polymerase Chain Reaction in Sjögren’s Syndrome, Rheumatoid Arthritis, and Behçet’s Disease

Objective: Autoimmune diseases are chronic conditions with largely unclear etiology, affecting patients’ quality of life and increasing healthcare costs. This study aimed to investigate the relationship between Rheumatoid arthritis, Sjögren’s syndrome, Behçet’s disease, and BK virus. Materials and Methods: This study was conducted between August 2017 and August 2018 in the Central Laboratory of the Department of Medical Microbiology. A total of 120 adults were enrolled, including patients diagnosed with Rheumatoid arthritis, Sjögren’s syndrome, Behçet’s disease (n=30 each) attending the Rheumatology outpatient clinic, and healthy controls from the General Internal Medicine outpatient clinic (n=30). BK virus was detected in urine and serum samples using Real-Time PCR. Multivariate logistic regression analysis was performed to identify independent factors associated with urinary BK virus positivity, including age and disease groups. Results: The mean ages were 43.03±19.43 years in controls, 54.33±12.03 in Rheumatoid arthritis, 50.76±10.29 in Sjögren’s syndrome, and 42.63±10.88 in Behçet’s disease groups. Urinary BK virus positivity was detected in 1/30 (3.3%) controls, 7/30 (23.3%) Rheumatoid arthritis patients, 7/30 (23.3%) Sjögren’s syndrome patients, and 4/30 (13.3%) Behçet’s disease patients. BK virus positivity was significantly higher in the Sjögren’s syndrome (p=0.016) and Rheumatoid arthritis groups (p=0.049) compared with controls. In multivariate logistic regression analysis, both Rheumatoid arthritis and Sjögren’s syndrome were identified as independent predictors of BK virus positivity (OR=8.83; 95% CI: 1.01–76.96; p=0.049). Although positivity was higher in Behçet’s disease patients, the difference was not statistically significant. Conclusion: Urinary BK virus positivity was significantly more frequent in patients with Rheumatoid arthritis and Sjögren’s syndrome than in healthy controls. These findings suggest a potential association between BK virus and certain autoimmune diseases. Larger, well-designed prospective studies are warranted to clarify the role of BK virus in autoimmune disease pathogenesis.