Examination of a-enolase autoantibodies in patients with biliary atresia

Objective To produce and purify recombinant human a-enolase protein, and to exmaine the level of a-enolase autoantibodies in serum of the patients with biliary atresia (BA). Methods The cDNA sequence of humana-enolase obtained by PCR was cloned into prokaryotic expression vector PET41-a. PET41-a was then transfected into E. coli BL21.The a-enolase protein expressed in E. coli BL21 was isolated and purified. During January 2006 to January 2011, 139 patients with BA and 49 healthy controls were recruited in this study. Their serum were collected, and IgG and IgM auto-antibodies to a-enolase were studied by ELISA. The patients who survived 2 years after Kasai procedure were grouped into 2 groups according to the level of IgG and IgM auto-antibodies to a-enolase in serum. The clinical data of the 2 groups was studied and compared. Results In BA group, there were 22 patients' OD value less than 0.5, 61 between 0.5-1, and 56 more than 1.In healthy controls, there were 33 patients' OD value less than 0.5, 12 between 0.5-1, and 4 more than 1.The OD value was statistically different between BA group and controls(P＜0.05). Seventy eight patients survived 2 years after Kasai procedure. The patients were divided into 2 groups according to whether or not their OD value reached 0.85.The postoperative jaundice clearance was significantly better in the patients whose OD value ＞0.85 compare with those whose OD value ＜0.85 (80％ vs 47％, x2 =9.018, P=0.003). The recurrent cholangitis was significantly lower in the patients whose OD value ＞0.85 compare with those whose OD value ＜0.85 (30％ vs 58％, x2 =6.617, P=0.013). The 2-year postoperative native liver survival rate was significantly better in the patients whose OD value ＞0.85 compare with those whose OD value ＜0.85 (60％ vs 47％, x2 =1.251, P =0.263). Conclusions Most of the BA patients have high level of a-enolase autoantibodies in serum. The level of the autoantibody was positively correlated with short-term outcomes. Key words: Biliary atresia;  Autoantibody