Changes of IL-12 and IL-17 levels in patients with autoimmune liver disease and its clinical significance

Abstract

Objective To investigate the expression of interleukin(ID-12 and IL-17 in the serum and liver tissues of patients with autoimmune liver disease(AILD) and to discuss the relevant significance.Methods The peripheral blood and liver tissues were collected from 21 patients with autoimmune hepatitis(AIH),21 with primary biliary cirrhosis(PBC),and 9 with AIH-PBC overlap syndrome(AIH-PBC OS).The serum IL-12 and IL-17 levels were assayed by ELISA,and the expression and location of IL-12 and IL-17 in the liver tissues were detected by immunohistochemistry method.Alamine transaminaseC ALT) andγ-glutamyltransferase(GGT) were measured by automatic biochemical analyzer.The correlation of serum IL-12 and IL-17 expressions with ALT and GGT levels was analyzed.Ten healthy participants taking a physical examination and 10 normal liver tissues were used as controls.Results The serum levels of IL-12 in AIH,PBC,and AIH-PBC OS groups were significantly lower than that in the control group(P0.01),and the serum levels of IL-17 in the three groups were significantly higher than that in the control group(P0.01).A negative correlation was found between serum IL-12 and IL-17 in AIH and PBC groups(AIH:r=-0.752,P0.05;PBC:r=-0.436,P0.05),and serum IL-17 was positively correlated with ALT and GGT(AIH:r=0.825,P0.05;PBC:r=0.571,P0.05).IL-12 was mainly expressed in bile duct epithelium and Kupffer cells,and the expression rates in the 3 experimental groups were significantly lower than that in the control group(AIH:19.05%[4/21],PBC:9.52%[2/21],AIH-PBC OS:11.11%[1/9],control:90.00%[9/10];P 0.01).IL-17 was mainly expressed in lymphocytes and monocytes,and the expression rates in the 3 experimental groups were significantly higher than that in control group(AIH:71.43%[15/21],PBC:76.19%[16/21],AIH-PBC OS:77.78%[7/ 9],control:10.00%[1/10];P0.01).IL-12 expression in the liver tissues was negatively correlated with IL-17 expression in AIH and PBC groups(AIH:r=-0.499,P=0.021;PBC:r=-0.580,P = 0.006).Conclusion IL-12 expression is reduced in AILD patients,decreasing the inhibition against Th17 cell differentiation,leading to IL-17 increase and mediating inflammatory injury,which indicates that IL-12/IL-17 inflammatory pathway may participate in the development and progression of AILD.