Clinical Significance of Pre- and Post-Transplant BAFF Levels in Kidney Transplant Recipients

It is well known that pre-transplant B cell activating factor (BAFF) levels are associated with the development of de novo anti-HLA antibodies and antibody mediated rejection post-transplant. However, the clinical significance of BAFF values at allograft rejection has not been determined. In this study, we investigated the clinical significance of pre-transplant BAFF level as well as post-transplant BAFF levels measured when indication biopsy was done. We checked for anti-HLA antibodies in 115 kidney transplant recipients who required allograft biopsy due to an increase in serum creatinine. With the same serum specimen, we measured BAFF levels, and in 78 of these patients, pre-transplant BAFF and anti-HLA antibody levels were detected as well. Patients in each group were divided into tertiles according to BAFF levels. We investigated the relationship between BAFF levels and the occurrence of anti-HLA antibodies. Pre-transplant BAFF levels showed significant association with pre-transplant sensitization, and also with early rejection (Tertile 3, 26.9% vs. Tertile 1, 11.5%; P<0.05). Post-transplant BAFF levels showed significant association with pre-transplant sensitization, but did not show association with anti-HLA antibodies and positive donor-specific antibodies at the time of biopsy. We did not find any association between post-transplant BAFF levels and allograft biopsy results, Banff scores and microvascular inflammation scores. In conclusion, pre-transplant BAFF levels are associated with pre-transplant sensitization and are useful in predicting allograft rejection. But post-transplant BAFF levels measured at the time of indication biopsy are not associated with the appearance of de novo HLA-DSA, allograft rejection, biopsy findings and other allograft outcomes.