Apoptosis of human umbilical vein endothelial cells (HUVEC) induced by IgA1 isolated from Henoch-Schonlein purpura children.

OBJECTIVE It had been shown that apoptosis of vascular endothelial cells played an important role in the pathogenesis of HSP. The present study was designed to investigate the apoptosis of vascular endothelial cells induced by isolated IgA1 from sera of HSP patients. METHODS HUVEC were cultured in 3 different types of media with IgA1 from HSP patients, normal healthy children and simply medium (blank control). Serum IgA1 was purified by jacalin affinity chromatography. The rates of apoptosis in HUVEC incubated with IgA1 were determined by the TUNEL method and flow cytometry, respectively. The expression of bax/bcl-2 and p53 was detected with the methods of Real-time PCR and Westernblot, respectively. RESULT The results showed that the apoptosis rate of HUVEC by IgA1 isolated from HSP patients was higher than that the normal controls (14.77±2.23% vs 9.97±1.48%) and blank controls (14.77±2.23% vs 2.25±0.77%) (P <0.01). Moreover the rate of HUVEC by IgA1 from normal healthy children was higher than the blank controls (9.97±1.48% vs 2.25±0.77%) (P <0.01). In addition, the bax and P53 expression were up-regulated and the Bcl-2 expression was down-regulated in HUVEC co-cultured with IgA1 isolated from HSP patients for 24 hours. CONCLUSIONS These findings suggested that IgA1 from HSP patients could induce the apoptosis of HUVEC, which might be related to the vascular endothelial injury of HSP.