T lymphocyte apoptosis in systemic lupus erythematosus patients

Apoptosis is a tightly regulated process and plays a crucial role in autoimmune diseases. Because abnormalities in apoptosis are considered to be involved in the pathogenesis of systemic lupus erythematosus (SLE), in present study we studied the apoptosis in T lymphocytes from Iranian SLE patients at protein and gene expression levels for some molecules which are involved in apoptosis pathways.

Thirty five SLE patients (23 female, 12 male), and 20 age matched controls (10 female, 10 male) participated in this study. T lymphocytes were isolated from peripheral blood mononuclear cells (PBMCs) using MACS method. Apoptosis rate was studied at protein level by flow cytometer using Annexin V, and at gene expression level using semi-quantitative RT-PCR method for detection of Fas, FasL, Bcl-2, caspase 8, and caspase 9 genes.

The percentage of apoptotic cells in SLE patients was not different in comparison with controls (20.2% ± 1.4 vs 21.1% ± 1.0), but the expression levels of FasL, caspase 8, and caspase 9 genes in all SLE patients and in female patients were significantly lower than controls; 0.45R vs 0.78R for FasL, 0.74R vs 1.0R for caspase 8, and 0.76R vs 1.26R for caspase 9 in all SLE patients and 0.37R vs 0.82R for FasL, 0.45R vs 1.6R for caspase 8, and 0.63R vs 1.56R for caspase 9 in female patients.

The expression levels of FasL, caspase 8 and caspase 9 molecules involved in apoptosis decreased in female, but not in male SLE patients.