Proliferation and activation induced cdl death of CD4 + T cells in childhood asthma

Abstract

Objective To investigate the correlation between immune inflammation and overactivity of T helper cells in childhood asthma by cell proliferation assay and activation induced cell death in vitro.Methods Th1/Th2/Th17 cytokines were determined by cytometric bead array.Cell proliferation and activation induced cell death were detected when CD4+ T cells were purified by magnetic beads and stimulated by PHA and antiCD3.At last,mRNA of Fas,FasL and Bcl-2 were mesured by real-time PCR.Results Cytokines of IL-4(2.451± 1.052ng/L vs 1.796 ±0.615 ng/L,P =0.018),IL-10( 1.920 ±0.813ng/L vs 1.390 ±0.162ng/L,P =0.006)and TNF(5.112 ±5.842 ng/L vs 1.506 ±0.551 ng/L,P =0.009) in sera of asthma group were higher than those in control group.Compared to control group,proliferation ability of CD4 + T cells in asthma group was greater ( OD450:0.498 ± 0.052 vs 0.274 ± 0.032,P ＜ 0.001 ) and apoptosis rate was lower( 35.62 ± 0.05 ％ vs 65.28±3.85％,P ＜0.001 ).mRNA expression of Fas in asthma group was lower but Bcl-2 was higher than those in control group.Conclusion It is implicated that defective expression of Fas and over expression of Bcl-2 in CD4+ T cells may contribute to apoptosis inhibition and cell proliferation,which could explain overeactivity of CD4 + T cells and lvmphocvte infiltration in childhood asthma. Key words: Childhood asthma; Proliferation; Apoptosis; Fas; Bcl-2