Expression of B-cell activating factor and its receptor in idiopathic thrombocytopenic purpura

Background B-cell activating factor (BAFF) plays a crucial role in B-cell development, survival, and immunoglobulin production. Excess BAFF results in the rescue of self-reactive B cells from anergy and the rescue of autoreactive T cells from the suppressing effect of dendritic cells, thus implicating a role in the development of autoimmunity. Aim The aim of this study was to evaluate BAFF and its receptor (BAFF-R) mRNA expression in patients with idiopathic thrombocytopenic purpura (ITP) and also to study the potential association of their expression with variations in disease severity, chronicity, and response to treatment. Patients and methods Evaluation of BAFF and BAFF-R expression was carried out using a quantitative real-time PCR, in 79 ITP patients as well as 20 age-matched and sex-matched control volunteers. Results The median expression level of BAFF and BAFF-R in ITP patients was significantly higher compared with that in the control group. Children had a significantly lower mean BAFF expression level compared with adults with ITP. Female patients had a significantly higher mean BAFF-R expression level compared with male patients. Patients with active ITP had a significantly higher BAFF expression compared with those in remission and those of the control group. The mean expression level of BAFF-R was significantly higher in patients with active ITP and in those in remission when it was compared with that of the control group. BAFF-R expression was significantly higher in steroid-treated patients compared with untreated patients. A significant positive correlation was found between BAFF and BAFF-R mRNA expression levels. BAFF expression was correlated positively with the median age of patients at the time of sampling and diagnosis. Conclusion Elevated BAFF expression in patients with active ITP indicates its possible role in the pathogenesis of ITP. Hence, selective antagonistic targeting of BAFF or BAFF-R in ITP patients with high levels of BAFF expression might be considered as a novel therapeutic strategy. (C) 2012 The Egyptian Society of Haematology.