Increased Fas ligand expression of peripheral B-1 cells correlated with CD4+ T-cell apoptosis in filarial-infected patients.

Abstract

Cellular hyporesponsiveness observed during helminth infections is attributed to factors such as antigen-presenting cells (APC) dysfunction, increased interleukin-10(IL-10), regulatory T cells and induction of CD4+ T (Th)-cell apoptosis. Increased Fas ligand (FasL) expression on the surface of B-1 cells and induction of apoptosis of Th cells by FasL-expressing B-1 cells due to helminth infection were demonstrated in murine model of helminth infection where as profile of FasL expression, Th-cell apoptosis and correlation between these two populations of cells in clinical filariasis remain unknown. In this study, we have scored the profile of apoptotic Th-cell population and FasL-expressing B-1 cells in different clinical categories of filariasis. The peripheral apoptotic T-helper cells were significantly increased in filarial patients compared to endemic controls. Expression of FasL on the surface of peripheral B-1 cells increased in filarial patients and positively correlated with peripheral apoptotic T-helper cells indicating FasL-expressing B-1 cells may be one of the important mediators of Th-cell apoptosis and immune anergy during filarial pathology.