Abnormal high expression of B-cell activating factor belonging to the TNF superfamily (BAFF) associated with long-term outcome in kidney transplant recipients.

B-cell activating factor belonging to the tumor necrosis factor superfamily (BAFF) is a critical regulator of B-cell maturation and survival. We investigated the expression of BAFF in peripheral blood sample from kidney transplant recipients. Results of flow cytometry showed that at 5 years or more posttransplantation, cell-surface BAFF was significantly expressed on peripheral CD3+ T lymphocytes kidney transplant recipients in compared with other groups (P < .05). BAFF expression was noted on CD4+ and CD8+ T cells. The BAFF messenger RNA level in peripheral mononuclear cells was consistent with the protein level. However, the serum soluble BAFF level varied among individuals in each group. Stratified by renal function, the cell-surface BAFF level was significantly higher in recipients with abnormal renal function compared with those with normal renal function (P < .05). Enzyme-linked immunosorbent assay results showed that expression level of cell-surface BAFF significantly correlated with panel reactive antibody. These results indicate that BAFF may be involved in the development of graft loss.