Expression of CD40L in CD4 + T cells from patients with systemic sclerosis

Objective To investigate the expression levels of CD40L in CD4 + T cells from systemic sclerosis (SSc) patients.Methods PBMC ( peripheral blood mononuclear cells) cells were isolated from the peripheral venous blood of SSc patients (16females,10males) and healthy donors (15females,10males) by density gradient centrifugation.CD4 + T cells were isolated using magnetic beads.mRNA levels of CD40L in CD4 + T cells were measured by real-time quantitative polymerase chain reaction (RTPCR).Flow cytometric analysis was used to detect the CD40L protein on the surface of CD4 + T cells.Results Both CD40L mRNA and protein expression in CD4 +T cells was significantly elevated in female SSc patients compared with female healthy controls [5.61 ± 1.86 vs 2.80 ±0.94,P ＜0.01 ; (6.70 ±3.55)％vs (2.37 ± 1.39)％,P ＜ 0.05,respectively].No significant increase in CD40L mRNA and protein expression was observed in male SSc patients compared with male controls [2.59 ± 0.89 vs 1.92 ± 0.56,P ＞0.05; (2.06±1.09)％ vs (2.13±0.87)％,P ＞0.05,respectively].Conclusions CD40L was overexpressed in CD4 + T cell of female patients but not males,which maybe one of the important reasons for female susceptibility to SSc. Key words: Scleroderma, systemic/ME;  CD40 ligand/ME;  CD4-positive T-lymphocytes