RESUMEN
Progressive multifocal leukoencephalopathy (PML) represents a rare but potentially fatal reactivation of JC-polyomavirus (JCPyV) recently also reported in patients with autoimmune diseases such as systemic lupus erythematosus and rheumatoid arthritis (RA) treated with rituximab. The aim of the present study was to analyse the pattern of JCPyV infections in patients with RA undergoing treatment with biologic agents. Urine and blood samples were analysed from 80 patients for antibody levels and/or the presence of JCPyV DNA. Genotyping of the control region and VP1 was performed for all JCPyV DNA-positive specimens. Viremia of JCPyV was only temporarily detected in two patients, and these viruses did not carry any mutations associated with the occurrence of PML. JCPyV DNA was prevalent in initial urine samples of 33% of all patients. RA patients who have consecutively been treated with two or more biologic agents revealed significantly higher prevalence of JCPyV DNA in the urine compared to RA patients treated with their first biologic agent. The presence of JCPyV DNA in the urine closely correlated to JCPyV antibody positivity, and therefore, antibody titres were higher in RA patients who had consecutively received two or more biologic agents over time. Therefore, the overall number of biologic agents had an impact on the pattern of JCPyV detection in this study. Hence, JCPyV antibody screening might be useful as part of the PML risk stratification for RA patients in the future.