B cell activation mediated by cluster of differentiation (CD) molecules plays an important role in B cell-related autoimmune diseases. CD22 and CD72 have been demonstrated to act as B cell inhibitory receptors in many autoimmune diseases. Activated B cells are involved in the pathogenesis of myasthenia gravis (MG) by secretion of anti-acetylcholine receptor (AchR) antibodies. However, the roles of CD22 and CD72 on B cells of MG are unknown. In this study, we detected the expression of CD22 and CD72 on B cells of MG, compared to multiple sclerosis (MS) patient controls and healthy controls by flow cytometry and quantitative real-time polymerase transcription chain reaction. Our data demonstrated that aberrant expression of CD72 exists on B cells of MG and MS patients and expression level of CD72 molecule has a significantly negative correlation with anti-AchR antibody levels in MG, which suggests that CD72 may be involved in the pathogenesis of MG and MS. There were no significant differences between study patients (MG, ocular MG, generalized MG, and MS) and healthy controls.
CD72 is a protein active in the immune system of animals. It consists of two identical halves, each of about 39-43 kD, and is a C-type lectin. Its primarily locus of expression is B-cells, where it appears to mediate aspects of B-cell - T-cell interaction. It is a ligand for CD5. The more CD72 on B cells the less autoantibody produced.