Measurement of the serum B-cell-activating factor of the tumor necrosis factor family (BAFF) in patients with idiopathic thrombocytopenic purpura and its correlation with immunosuppressive therapy

Background The B-cell-activating factor of the tumor necrosis factor family (BAFF) is a homotrimeric type 2 transmembrane protein that also exists in a soluble form. It belongs to the family of tumor necrosis factor ligands and is expressed at the surfaces of myeloid cells and antigen-presenting cells and induces B-lymphocyte proliferation and immunoglobulin secretion. Aim of the study The aim of this study was to assess the serum BAFF level in patients with idiopathic thrombocytopenic purpura (ITP) and to determine the correlation of its level with response to immunosuppressive therapy (corticosteroids). Participants and methods The study included 60 participants: 40 patients with newly diagnosed ITP who were followed up for 3 months after immunosuppressive therapy (steroids), divided into responders and nonresponders, and 20 healthy control individuals. Results The serum BAFF level was lower in the controls (mean +/- SD 3.4 +/- 2.2 ng/ml) than the ITP patients (responders and nonresponders) before treatment (mean +/- SD 19.8 +/- 2.9 and 20.5 +/- 8.8 ng/ml, respectively) with a statistically highly significant difference (P< 0.001), but no significant difference between the responders and the nonresponders. After treatment, the BAFF level was still high in the nonresponder group (mean +/- SD 18 +/- 7.6 ng/ml), with a statistically highly significant difference in comparison with the responders and the controls (mean +/- 3.6 +/- 1.9 and 3.4 +/- 2.2 ng/ml, respectively) (P< 0.001). It was found that BAFF decreased markedly among all the participants and in the responder group, with a statistically highly significant difference between them and the nonresponder group. The percentage of change was 84% among responders compared with 10% only among nonresponders. In addition, the BAFF level was inversely correlated with the platelet count. Conclusion The serum BAFF level increases in patients with ITP and reverts to normal after treatment in responders but remains high in nonresponders. We recommend further randomized-controlled clinical trials exploring the role of drugs acting on BAFF in the treatment of autoimmune disorders. (C) 2012 The Egyptian Society of Haematology.