The Abnormal High Expression of B Cell Activating Factor Belonging to TNF Superfamily (BAFF) and Its Potential Role in Kidney Transplant Recipients

B cell activating factor belonging to TNF superfamily (BAFF) is a critical regulator of B cell maturation and survival. In this present study, the expression characteristic of BAFF in kidney transplantation recipients was investigated, its potential significance was analyzed and peripheral blood of follow-up kidney transplant recipients was studied. Flow cytometric assay results showed that, cell-surface BAFF was significantly highly expressed on peripheral CD3+ T lymphocytes in ≥ 5 yrs group of kidney transplant recipients, compared with other groups (p < 0.05). BAFF expression could be found on CD4+ T cells and CD8+ T cells. The BAFF mRNA levels in peripheral mononuclear cells were consistent with the protein levels. However, serum soluble BAFF levels were inter-individually different in each group. Stratified by renal function, it was found that cell-surface BAFF levels were significantly higher in those with abnormal renal function, compared with recipients with normal renal function (p < 0.05). ELISA assay results showed that expression levels of cell surface BAFF were significantly correlated with anti-HLA Ⅰ & Ⅱ antibodies. These results indicate that BAFF may be involved in the development of graft-loss and influences the long-time outcome of kidney allograft, likely mediated by interfering with immune response.