Evaluation of polyomavirus BK reactivation in lupus patients who underwent kidney transplantation

Background. A pathogenic role for polyomavirus BK in systemic lupus erythematosus (SLE) has been proposed, however no study evaluated the occurrence of BK replication in renal transplant recipients according to the underlying disease leading to transplantation and its potential impact. Methods. The occurrence of BK reactivation was serially evaluated in 468 renal transplant recipients, including 11 patients with SLE as underlying disease (overall, 2370 serum and 2370 urine specimens; 65 from SLE patients). Results. Considering the overall occurrence of viral reactivation (viremia and/or viruria), 26/65 (40%) specimens were positive in four SLE patients (36.3%) versus 331/2143 (15.4%) in 130/227 (57.3%) non-SLE patients. A patient transplanted for class III lupus nephritis evidenced sustained BK viremia and viruria (with viremia values potentially indicative of polyomavirus-associated nephropathy) in the absence of clinical features of renal dysfunction or recurrence of lupus nephritis. Conclusions. Further studies on larger populations and for a longer follow-up should be required to evaluate the impact of BKV reactivation in renal transplant patients with SLE as underlying disease, as well as the potential therapeutic implications.