BK virus nephropathy in a native kidney.

BACKGROUND

BK virus is a polyoma virus which has been associated with impaired graft function in kidney transplant recipients. After primary infection, the virus becomes latent in the renal/urinary epithelium. In immunocompetent hosts, there are usually no pathological sequelae.

CASE: An 11-year-old female on chronic immunosuppression for a severe auto-immune/inflammatory condition was referred to Paediatric Nephrology due to a persistently elevated serum creatinine. Extensive investigation yielded BK viruria and viraemia. Kidney biopsy showed multifocal lymphocytic tubulitis, with cytonuclear changes. Immunohistochemical staining for SV40 was positive, and a diagnosis of native kidney BK virus nephropathy was made.

CONCLUSION

We present the first non-malignancy/transplant-associated paediatric case of BK virus nephropathy in a native kidney. In an era of increasing use of immunosuppressive medicines for a variety of indications, clinicians should include BK virus infection in their differential diagnosis for nephropathy in patients on chronic, high-dose immunosuppression.