BK virus assessment in lupus nephritis: is this a potential trigger for disease activity?

Andrés Franco, Centro de Nefrología, Hospital de Clínicas Dr Manuel Quintela, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay
José Boggia, Centro de Nefrología, Hospital de Clínicas, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay
Jimena Cabrera, Centro de Nefrología, Hospital de Clínicas Dr Manuel Quintela, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay
Gabriela Ottati, Centro de Nefrología, Hospital de Clínicas, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay

Objective: The BK virus (BKV) is a human polyomavirus widely distributed in the population. In deeply immunosuppressed patients, such as those undergoing renal transplantation, the virus can be reactivated, leading to BKV nephropathy; the main risk factor is the degree of immunosuppression. Limited literature analyzes BKV infection in lupus nephritis (LN). Our objective was to study the BKV in LN. Material and methods: Patients over 18 years with LN confirmed by histology were prospectively studied for 1 year at the University Hospital. BKV viremia was detected and quantified using real-time-polymerase chain reaction. Results: Twenty-seven patients were included, 85% were women. About 100% were perceived as Caucasians. The 77.8% had proliferative LN at the debut, and the median evolution time was 11.5 years (IQR: 4.0-16.8). At enrollment, all patients received immunosuppressive treatment with prednisone (62%), mycophenolate (85%), and/or hydroxychloroquine (89%). We did not obtain positive viremia in any patient. At the time of blood sampling, 100% were in remission, and of them, 89% were in complete remission. Conclusions: We did not detect any patients with positive BKV viremia. The absence of viremia could be due to the high degree of remission and low immunosuppressive burden in this population.

Keywords: Lupus erythematosus systemic. Kidney diseases. Lupus nephritis. Immunosuppressive agents. BK virus.