Abstract: Objective To investigate the characteristics of fibrosis stage in chronic hepatitis B (CHB) patients with low level of hepatitis B surface antigen (HBsAg) and its correlation with platelet (PLT) count. Methods One hundred and thirty-six CHB patients with low HBsAg admitted to our hospital from April 2018 to April 2020 were included. They were divided into S1 group (n=28), S2 group (n=37), S3 group (n=40), and S4 group (n=31) according to the stage of liver fibrosis. At baseline, the PLT, type Ⅲ collagen (PC-Ⅲ), collagen type Ⅳ collagen (C Ⅳ), hyaluronic acid (HA), and laminin (LN) were detected in all patients.The stage of liver fibrosis was evaluated. The levels of PC, PC-Ⅲ, C Ⅳ, HA and LN of the four groups were compared, Spearman coefficient test was used to analyze the correlation between PLT level and PC-Ⅲ, C Ⅳ, HA and LN in CHB patients with low level of HBsAg. Results PLT levels of S1 group, S2 group, S3 group and S4 group were (220.7±85.4) × 10⁹/L, (169.2±66.4) × 10⁹/L, (135.7±52.6) × 10⁹/L, and (104.5±40.1) × 10⁹/L, respectively. The PLT level of the four groups from the highest to the lowest was in order as follows: S1 group, S2 group, S3 group, S4 group. The difference was statistically significant (P<0.05). Serum levels of PC-Ⅲ, C Ⅳ, HA, and LN of S1 group were (95.5±34.3) μg/mL, (61.2±15.7) μg/mL, (84.3±25.6) ng/mL, (88.4±15.4) ng/mL, respectively; of S2 group were (130.5±48.6) μg/mL, (79.3±20.4) μg/mL, (115.3±30.6) ng/mL, (102.8±22.8); of S3 group were (166.4±62.7) μg/mL, (90.4±25.3) μg/mL, (155.5±45.1) ng/mL, (115.6±29.3) ng/mL and of S4 group were (223.7±80.9) μg/mL, (105.5±31.9) μg/mL, (224.3±79.3) ng/mL, (226.3±34) ng/mL. The indicators of the four groups from the lowest to the highest was in order as follows: S1 group, S2 group, S3 group, S4 group, and the difference was statistically significant (P<0.05). Correlation analysis showed that serum PLT level was negatively correlated with the levels of PC-Ⅲ, C Ⅳ, HA and LN in CHB patients with low levels of HBsAg, r=0.584, 0.521, 0.499, 0.544, respectively, P<0.05. Conclusion When the serum PLT level decreases significantly, the levels of serum PC-Ⅲ, C Ⅳ, HA and LN rise obviously in CHB patients with low level of HBsAg, suggesting the close relationship between the level of HBsAg and PLT, which may help to evaluate liver histological damage.

Key words: Chronic hepatitis B, Hepatitis B surface antigen, Hepatic fibrosis stage, Platelet count