Virus detected in blood in up to 46% of patients in the first six months after renal transplantation.


CHICAGO—Spanish researchers say they have found a high rate of BK virus (BKV) viremia during the first six months after renal transplantation, but after that the rate declines significantly.

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In a study of 47 renal transplant recipients (mean age 46 years; range, 35-58 years) at a Madrid hospital, the incidence of BKV viremia ranged from 22% to 46% in the first six months after kidney transplantation before falling off sharply. No cases of nephropathy caused by BKV were detected during the study period or to date, suggesting that it may not be necessary to test intensively for BKV during the first months after transplantation, said study investigator Patricia Muñoz, MD, professor of microbiology and an infectious disease specialist at the Hospital General Universitario Gregorio Marañón in Madrid.


“It is very labor intensive, so surveillance may be done less frequently until the technique is more widely commercialized and more widely available.”


Previous studies have shown BKV infection is an important cause of chronic renal dysfunction that results in graft loss in 2%-9% of kidney transplant patients.


The researchers, who presented their findings here at the 47th Interscience Conference on Antimicrobial Agents and Chemotherapy, obtained 181 urine and 181 blood samples from patients at week 1 and at months 1, 3, 6, 9, 12, 15, and 18 after transplantation.


At week 1, the researchers detected viruria and viremia in 49% and 22% of subjects, respectively. The proportions of viruria and viremia were 36% and 26% at month 1, 46% and 32% at month 3, 62% and 48% at month 6, 53% and 6% at month 9, 54% and 8% at month 12, 60% and 10% at month 15, and 33% and 0% at month 18.


The median creatinine level (mg/dL) at week 1 was 5.8 in viremic patients compared with 3.9 in non-viremic patients. The levels were 2.5 and 2.0 at month 1, 1.5 and 1.8 at month 3, 1.6 and 1.8 at month 6, 1.1 and 1.6 at month 9, 0.9 and 1.7 at month 12, 1.0 and 1.6 at month 15, and 1.2 and 1.2 at month 18. Only one patient suffered renal dysfunction attributed to BKV and the problem resolved after reduction of immunosuppression.


During the first 18 months following transplantation, viruria and viremia occurred at least once in 68% and 44% of patients, respectively.