Abstract: Objective:To detect the level of soluble inducible co-stimulator molecule (sICOS) and soluble programmed death protein 1 (sPD-1) in peripheral blood supernatant in patients with chronic hepatitis B and then discuss its significance with other index. Methods: Eighty patients with CHB and thirty healthy persons were enrolled in our study. the peripheral blood supernatant were collected and isolated the peripheral blood mononuclear cells (PBMCs) in CHB patients . According to the clinical HBsAg and HBeAg results, the CHB patients can be divided into the HBeAg(-) group and the HBeAg(+) group, simultaneously,the HBeAg(+) group was divided into two parts: the immune tolerance group and immune clearance group.The sICOS and sPD-1 expression in the peripheral blood was measured by enzyme-linked immunosorbent assay (ELISA).the mRNA expression of ICOS、PD-1 and PD-1Δex3 in PBMCs of patients with CHB were detected by real-time quantitative reverse transcription polymerase chain reaction(RT-qPCR). Results sICOS level was significantly higher in CHB patients compairing the healthy controls(p<0.05); as same as the HBeAg(+) persons , sPD-1 was increased(p<0.01), in which the sPD-1 level was increased more obviously in patients who were in immune clearance phase than those in immune tolerance phase(p<0.05). sPD-1 was positively correlated with the AST levels in CHB patients( p<0.01); The sPD-1 was only correlated with the ALT levels in the HBeAg(+) patients( p<0.01). But there is no correlation between sICOS levels and the ALT or AST levels.A weakly negative correlation between HBV-DNA and sICOS levels was observed (p<0.05). Whereas the sICOS did not correlate with HBeAg levels.Compared with the healthy controls, before the activation and stimulation, the ICOS mRNA expression were decreased in two CHB groups (p<0.05).Conclusion:The sICOS and sPD-1 levels were significantly higher in the serum of patients with CHB and they may be able to participate in the development of CHB.

Key words: ICOS, PD-1, chronic hepatis B