Interleukin-10 Is Associated With Immune Phases Of Patients With Chronic Hepatitis B

Background and ObjectiveHepatitis B virus (HBV) infection is one of the major global public health problems and life-threatening consequences for patients. It is estimated that there are approximately 350-400 million HBV carriers in the world. Even with the advent of an effective hepatitis B vaccine, more than 50 million new cases of HBV infection occurs annually. Although the majority of HBV infected adults recover spontaneously, 5-10% of patients develop chronic HBV infection (carriers, chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma), and 15%-40% chronic HBVpatients will develop serious complicantions during their lifetime. It is now recognized that the natural course of chronic hepatits B (CHB) is typically divided into four phases:the immune-tolerant (IT) phase, the immune clearance (IC) phase, low or no-replicative (LR) phase and hepatitis B e antigen (HBeAg)-negative hepatitis (ENH) phase. Although the exact pathophysiology of the development of chronic HBV is not well understood, increasing envidences indicated that effective T-cell responses are crucial for the clearance of viral infection. Aberrant immune response in chronic HBV infection plays a key role in the impairment of HBV clearance. Interleukin-10 (IL-10) is an anti-inflammatory cytokine with a crucial role in preventing inflammatory and regulates the response of T helper type 2 (Th2) cell. Previous studies showed that upregulation of IL-10 were associated with suppressed T-cell responses and chronicity of HBV infection. In our study, we intend to determine the expression of IL-10 and its associated cytokines at gene and protein levels, and then assess the role of IL-10 in the natural history of chronic HBV infection with different immune phases.Patients and MethodsA total of 197 patients with chronic hepatitis B were included, including 40 for immune tolerance (IT) phase,97 immune clearance (IC) phase,26 low replication(LR) phase,34 for HbeAg negative hepatitis B(ENH) phase, as well as 18 healthy controls.The level of IL-10, IL-6 and TNF-α in plasma was determined using enzyme-linked immunosorbent assay (ELISA).The level of IL-10, IL-6 and TNF-α in peripheral blood mononuclear cells (PBMCs) was determined using quantitative real-time polymerase chain reaction(RT-PCR). All statistical analyses were preformed using the IBM SPSS 22.0 software (SPSS Inc., Chicago, IL, USA). Data were presented as median values and interquartile ranges (median [centile 25; centile 75]). Comparison between groups was analyzed by the Kruskal-Wallis H analysis. Mann-Whitney U test was used to compare the quantitative variables between two groups.Spearman rank correlation test was used to compare the correlation between variables. Differences were considered statistically significant at a two-tailed P< 0.05.Results1. The plasma levels of IL-10 in chronic hepatitis B patients were significantly higher than healthy controls (all P< 0.05), as well as mRNA levels shared the same condition. Compared IL-10 expression at plasma and mRNA levels stratified by HBeAg and HBVDNA, the results shown that a significant higher level of plasma IL-10 in HBeAg positive patients compared with HBeAg negative patients (Z=-2.591, P=0.01). we did not find any significant difference of IL-10 between CHB patients with HBVDNA positive and those without HBVDNA positive at two levels (Z=-1.915,P= 0.099; Z=-1.648,P= 0.055).2. The levels of IL-10 associated cytokines IL-6 and TNF-α in chronic hepatitis B patients were significantly higher than healthy controls (P< 0.05). IL-10 mRNA in patients with CHB was positively correlated with IL-6 mRNA (r=0.344, P<0.01); whereas negatively correlated with TNF-α mRN A (r=-0.298, P<0.01).Plasma IL-10 in patients with CHB was also positively correlated with plasma IL-6 (r=0.514, P<0.01); whereas negatively correlated with plasmaTNF-α(r=-0.363, P<0.01).3. IL-10 at mRNA and plasma levels in patients with CHB was positively correlated with ALT (r=0.392, P<0.01, r=0.264, P<0.01) and AST(r=0.290, P<0.01; r=0.184,P=0.01)4. There were significant differences of IL-10 at gene and protein levels in the natural history of chronic HBV infection with different immune phases. The expression of IL-10mRNA in IC phase was significantly higher than that in IT phase (P<0.001) or LR phase, whereas we also observe significantly difference of IL-10 mRNA between ITgroup and ENH group (P=0.01). At protein levels, plasma IL-10 in IC phases was significantly higher than IT phase (P< 0.05) or LR phase (P< 0.05). However, we did not find any significant differences of IL-6 and TNF-α within any two of the four phases using Kruskal-Wallis H analysis.ConclusionsThe expression of IL-10 in IC phase was significantly higher than that in IT phase or LR phase at gene and protein levels, whereas we also observe significantly difference of IL-10 mRNA between ITgroup and ENH group.the level of IL-10 expression were associated with the degree of liver inflammation. In summary, IL-10 might contribute to immune phases of chronic HBV infection.