BK virus

An exerpt from http://findarticles.com/p/articles/mi_qa4117/is_200409/ai_n9458266

BK virus in kidney transplantation: a case study

Progress in Transplantation, Sep 2004 by Boyum, Denise

Prevention as well as treatment of viral infections in transplant recipients relies on minimal immunosuppressive therapy consistent with graft survival and the use of antiviral therapies in proportion to perceived risk. BK virus creates an even greater challenge in posttransplant management and graft survival because of difficulty in diagnosing and treatment. BK nephropathy develops in 1 % to 5% of transplant recipients, with loss of allograft function occurring in 50% of the cases. We present a case of a 67-year-old man who developed BK virus allograft nephropathy 9.5 months after transplantation. His allograft function was extended through rigorous treatment with an antiviral agent, reduction of immunosuppressant, and monitoring in an outpatient setting. (Progress in Transplantation. 2004; 14:176-180)

Also from Wikipedia

The BK virus is a member of the polyomavirus family. Past infection with the BK virus is widespread, but significant consequences of infection are uncommon, with the exception of the immunocompromised and the immunosuppressed.

The BK virus was first isolated in 1971 in the urine of a renal transplant patient, initials B.K.[1] This BK virus is similar to another virus called the JCV since their genome sequence share 75% homology. Both of these viruses can be identified and differentiated from each other by carrying out serological tests using specific antibodies.

The BK virus rarely causes disease since many people who are infected with this virus are asymptomatic. If symptoms do appear then many of them will be mild such as having a respiratory infection or a fever. These are known as the primary infections. Latent infections can occur in the kidneys and sometimes in the brain. A latent infection occurs when the virus becomes reactivated. However it is not known how this virus is transmitted. It is known however that the virus is spread from person to person and not from an animal source. It has been suggested that this virus may be transmitted through respiratory fluids.

In some renal transplant patients, the necessary use of immunosuppresant medications has the side-effect of allowing the virus to manifest itself and ultimately attack the kidney via BK nephropathy.[2] It is also associated with ureteral stenosis and interstitial nephritis. In bone marrow transplant recipients it is notable as a cause for hemorrhagic cystitis. In addition, the presence of BK polyoma in the bladder is statistically linked to the development of bladder carcinoma.[3]

This virus can be diagnosed by BKV blood & urine testing, in addition to carrying out a biopsy in the kidneys. PCR techniques and LAMP (Loop mediated isothermal amplification) can also be carried out to identify the virus.[4] Renal transplant patients infected with this virus can be treated by using cidofovir which is an antiviral drug. Cidofovir is a nucleotide analogue that has the ability to interfere with the action of the BK virus. It is known to have treated individuals with a renal transplant that were infected with this virus. In addition, therapy with leflunomide, an anti-inflammatory drug approved for the treatment of rheumatoid arthritis, is now widely prescribed. The drug acts not only as an antiviral effective against BK but also as an immunosuppresant, particularly promising for renal transplant recipients.[5]

I have not had it yet, but have been tested for it on each hospital visit.