Introduction:

Nephropathy from BK virus is a significant complication of kidney transplantation and occurs following a period of viremia. Patients who are HLA mismatched and more highly sensitized (PRA>20%) receive stronger induction immunosuppression (thymoglobulin). The purpose of this study is to determine whether BK viremia (BKV) and BK nephropathy (BKN) is related to specific HLA phenotype or higher in HLA mismatched patients and or elevated cPRA.

Methods:

We conducted a retrospective analysis of 537 kidney transplant patients from 2009 to 2017. Of these, 122 developed significant BKV (PCR>10,000 copies) and 21 viremic patients developed BKN compared to 414 control patients. Maintenance immunosuppression consisted of tacrolimus, mycophenolate and tapered prednisone. Degree of HLA (A, B, DR) mismatching (0-2, 3-4 and 5-6 mismatch) as well as cPRA were determined for groups with BKV (n=122), BKN (n=21) and the control group (n=414). Also, risk of BKV or BKN according to age, ethnicity, gender and live versus deceased donor was determined.

Results:

There was no significant difference in HLA mismatch (0-2, 3-4 or 5-6) between the BKV and the control groups. There was also no significant difference in HLA mismatch between patients who had biopsy proven BKN compared to patients who did not. There was no significant difference in cPRA (class I or class II) between the groups. Furthermore, there was no specific HLA phenotype that was more prevalent in the BKV, BKN groups versus control. The only significant risk factor for developing BKN was male gender (p= 0.037).

Conclusion:

The risk of BKV and BKN is not associated with a specific HLA phenotype or the degree of HLA mismatch. Moreover, cPRA percentage is not a risk factor for BKV or BKN. Male gender is a significant risk factor for developing BKN.

CITATION INFORMATION: Suleiman B., Saleh S., Hassan W., Wang K., Maibam A., Karim A., Hines A., Mei X., El-Husseini A., Yaseen M., Cornea V., Castellanos A., Gedaly R., Waid T. HLA Mismatching and cPRA Do Not Affect BK Viremia and Nephropathy Risk in Kidney Transplantation: A Retrospective Analysis Am J Transplant. 2017;17 (suppl 3).

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