| Objective:In spite of a large amount of researches have already proved the significance of malfunctional HBV-specific inmmune response in the chronicity of HBV infection, which is known as a major cause of chronic liver injury and regulated by lots of immune factors, the concrete mechanism of the chronicity is still a complex progress to explain. T cell immunoglobulin and mucin-3(Tim-3) was first reported and described as a protein selectively expressed on Th1 cells that plays an important part in the regulation of immune system. The present study aims at investigating the serum Tim-3 levels among the chronic hepatitis B(CHB) patients, HBV related acute-on-chronic liver failure(ACLF) and healthy controls in serum and liver tissue, hopefully to draw a conclusion describing the connection between the expression and liver inflammation degree and to explore the value of Tim-3 in the progression of HBV infection.Methods: A total 48 subjects were enrolled in our study and divided into 3 groups including 25 CHB patients, 23 HBV related ACLF patients and 20 healthy controls. All of the patients were randomly selected from the inpatients or outpatients of the Third Hospital of Hebei Medical University from June 2013 to December 2014, and the controls were also recruited from the medical examination center of the very hospital at the same period. We also collected 54 liver tissues of the CHB patients who underwent liver biopsy, and divided into 3 groups according to different inflammation extents: mild group, moderate group and severe group. All of the CHB and HBV related ACLF patients were diagnosed according to the Guidelines on Prevention and Treatment for Chronic Hepatitis B in China(2010 edition) or the Diagnostic and Treatment Guidelines for Liver Failure(2012 edition) developed by the Chinese Society of Hepatology and the Chinese Society of Infectious Disease respectively. We examined the regular serum biochemical indexes along with HBV DNA load, and performed enzyme-linked immunosorbent assays(ELISA) to value the serum levels of Tim-3 and interferon γ(IFN-γ). Then we measured the expression in liver tissue by immune- histochemical staining and the Tim-3 m RNA expression in liver tissues by quantitative real-time polymerase chain reaction.Results:1 The demographic data of the subjects were comparable. CHB patients had a obviously higher albumin level but lower alanine transaminase(ALT), aspartate transaminase(AST), total bilirubin(TB) and direct bilirubin(DB) levels than HBV related ACLF patients, P all < 0.01. The difference of serum HBV DNA load between CHB group and ACLF group not statistically significant, P > 0.05.2 CHB patients and ACLF patients had a higher serum Tim-3 levels than healthy controls, and compared with CHB patients, the serum Tim-3 levels of ACLF patients were also higher. All the differences was statistically significant( P < 0.05 or P < 0.01).3 Significant variations of IFN-γ concentration in serum of different groups were showed in the results. CHB patients had a obviously lower IFN-γ levels( 318.75 ± 506.85 pg/ml) in serum than healthy controls( 759.62 ± 160.38 pg/ml, P < 0.05), while ACLF patients( 2898.34 ± 2464.51 pg/ml) had the highest IFN-γlevels compared with CHB patients( P < 0.01) and healthy controls( P < 0.05).4 Correlation between serum Tim-3 expression and regular laboratory indexes. The Tim-3 levels in serum were positively correlated with serum ALT levels( r = 0.6468,P < 0.01) in CHB patients. In ACLF group, the Tim-3 levels in serum were found negatively correlated with ALB levels( r =- 0.4422,P < 0.01), positively related with ALT and AST levels(r = 0.7423, 0.8006 respectively, P both < 0.01). The correlations between serum Tim-3 expression with HBV DNA load were not found in any groups.5 Tim-3 expressions in CHB liver tissues were significantly relevant with liver inflammation grades. Mass of Tim-3+ cells were detected in the tissues with obvious inflammation by microscope. The differences among 3 groups were significant while the severe group( 317.7 ± 74.2 /hpf) had the most Tim-3+ cells in tissues under microscope compared to moderate group( 19.9 ± 10.0 /hpf) and mild group( 19.9 ± 10.0 /hpf), P all < 0.01. We found the counts of Tim-3 positive cells were significantly relevant with the liver inflammation grades( r = 0.9227, P < 0.001).6 Tim-3 m RNA expressions in liver tissues were higher in CHB and HBV related ACLF patients. Quantitative real time PCR was performed in a total of 36 liver tissues collected from enrolled subjects. Results showed ACLF group had the highest Tim-3 m RNA levels( 2.681 ± 0.34) than CHB group( 1.20 ± 0.39) and healthy controls( 0.36 ± 0.19), and the differences were statistically significant( P all < 0.01).Conclusions:1 Expressions of Tim-3 in CHB patients were up-regulated along with lower IFN-γ levels, suggesting Tim-3 might have the ability to interfere synthetic section and/or secretion of IFN-γ and play an essential part in the chronicity of HBV infection.2 Tim-3 levels were significantly correlated with the inflammation degrees in CHB patients, suggesting Tim-3 was involved in the immunology injury and the aggravation of HBV infection. |
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