COMPLICATIONS - INFECTIONS

F. Velez-cubian, J. Marquez-graciani, L. Morales-otero, Z. Gonzalez-caraballo, C. Del coro-amengual, F. Rivera, E.A. Santiago-delpin
Transplant Center, Auxilio Mutuo Hospital / Univ. of Puerto Rico, San Juan/PUERTO RICO

Body: Purpose: To identify factors associated with BK virus infections in Hispanic kidney transplant recipients, and determine outcomes. Methods: In this retrospective study we included patients diagnosed with BKV either by kidney biopsy or PCR in plasma and/or urine. A total of 37 patients were diagnosed with BKV infection from 1998 to 2009. These patients were compared to a randomly selected control group with negative PCR results for BKV infection. We compared age, sex, B.M.I., type of donor, cause of ESRD, creatinine levels, induction and maintenance immunosuppression dose and levels. In the BKV infected patients we analyzed treatment, time after transplant to diagnosis, biopsy and PCR results and disease progression. The data was analyzed with parametric and non parametric statistics. Statistical significance was defined as p<0.05. Results: There was no significant difference in sex, age, BMI between the two groups. Donor types for the BK virus infected group were 86% cadaveric and 14% living donors compared to 74% and 26%, respectively, in the control group (p=0.09). The mean creatinine levels at diagnosis were 2.1 for the BKV positive group and 1.7 for the control group (p=0.10). The induction therapy received by the BKV group was 80% Thymoglobulin and 20% Simulect, compared to 65% and 35% respectively for the control group (p=0.14). Tacrolimus levels at diagnosis was 11.3 ± 4.4 ng/ml for the BKV group compared to 9.3 ± 3.7 for the control group (p=0.06). BKV infected patients had multiple periods of high tacrolimus levels (p=0.03) and extreme levels of over 20ng/ml (p=0.05) compared to the control group. Sirolimus levels at diagnosis were 5.3 for the BKV group compared to 4.3 for the control group (p=0.4). Cyclosporine levels at diagnosis were 200 for the BKV group, compared to 114.33 for the control group (p=0.14). There was no significant difference between the two groups for dose at the time of diagnosis for tacrolimus, sirolimus, cyclosporine, prednisone, mycophenolate and mycophenolic acid. The most common kidney biopsy finding in the BK virus infected group was acute tubulointerstitial nephritis with 32%, and acute allograft rejection with 29%. BKV infected patients had 24% graft loss, 8% resolved and 68% continued infected. BKV patients had more rejections (9) than non BKV (2) (p=0.02). More kidneys were lost in BKV patients (9) than non BKV (0) (p=0.001). Conclusions: BKV infected patients are more inmunosuppressed than non-BKV infected patients due to more episodes of high tacrolimus levels and extreme values usually associated with toxicity. The coincidence of rejection with BKV carries a particularly poor graft prognosis. Our resulting strategy is to avoid high tacrolimus levels in all transplant patients, and to decrease immunosuppression in BKV infected patients. Leflunamide may be used as rescue.

Disclosure: All authors have declared no conflicts of interest.