In 1971, a human polyomavirus was discovered from the urine of a renal transplant recipient whose initials were B.K. This virus has been named BK virus. First time BK virus infections occur in early childhood in many people, typically without any symptoms. Later in life, the virus remains quiet (latent) but present in the kidneys. Almost all illnesses caused by BK virus occur in those receiving immunosuppression after an organ transplant or those with other acquired immune system deficiency. BK virus is estimated to cause a progressive kidney transplant injury in 1-10% of renal transplant recipients.
Actual damage in the kidney can be detected by a kidney biopsy. Kidney injury develops late in the course of BK virus disease and screening and early treatment is beneficial for long-term transplant survival. Screening for the BK virus in kidney recipients usually occurs via blood or urine tests. Our program routinely screens for BK virus to allow for early detection and treatment. Reducing the amount of immunosuppressive (anti-rejection) medication can help to decrease the virus. A medication called leflunomide has also been shown to inhibit BK virus in the blood which prevents injury to the transplanted kidney.