BK virus

BK virus is a member of the Polyomavirus family, which was first isolated in 1971 from the urine of a renal transplant patient named B.K. The virus is a significant cause of morbidity in renal transplant recipients and is associated with nephropathy and hemorrhagic cystitis.

History

The BK virus was first identified in 1971 in a renal transplant patient, initials B.K., suffering from ureteric stenosis. The virus was isolated from the patient's urine. Since then, BK virus has been identified in a variety of patient populations, including those with immunosuppression due to HIV/AIDS or organ transplantation.

Virology

BK virus is a non-enveloped, double-stranded DNA virus in the Polyomavirus family. It has a circular genome of approximately 5,000 base pairs. The virus is divided into early and late regions, which encode for the T antigens and capsid proteins, respectively.

Clinical significance

BK virus is a significant cause of morbidity in renal transplant recipients, where it can cause BK virus-associated nephropathy (BKVAN). This condition can lead to graft loss in up to 80% of affected individuals. The virus is also associated with hemorrhagic cystitis, particularly in hematopoietic stem cell transplant recipients.

Diagnosis

Diagnosis of BK virus infection is typically made through the detection of viral DNA in the blood or urine using polymerase chain reaction (PCR). Histopathology can also be used to confirm the diagnosis in cases of BKVAN.

Treatment

There is currently no specific antiviral treatment for BK virus. Management typically involves reduction of immunosuppression, which can lead to clearance of the virus. In cases of BKVAN, leflunomide and ciprofloxacin have been used with some success.

Epidemiology

BK virus is widespread in the human population, with seroprevalence rates of 60-80% reported. The virus is typically acquired in childhood and remains latent in the renal and urinary tract. Reactivation can occur in the setting of immunosuppression.

See also

• JC virus
• Polyomavirus-associated nephropathy
• Hemorrhagic cystitis