Complement C4a inhibits the secretion of hepatitis B virus screened by surface-enhanced laser desorption ionization time-flight mass spectrometry-based ProteinChip analysis

PURPOSE

Chronic hepatitis B (CHB) is a kind of chronic liver disease caused by persistent hepatitis B virus (HBV) infection. The study aims to seek the factors of host resistance to HBV and investigate their roles.

EXPERIMENTAL DESIGN

Protein profiles of 58 healthy controls and 121 CHB patients were obtained by SELDI-TOF/MS. Predicted protein was validated by ELISA. Protein expression was evaluated by Western blot in the persistently HBV expressing cell line HepG2.2.15 and non-HBV expressing cell line HepG2. The level of HBV DNA was subsequently detected by quantitative real-time PCR in HepG2.2.15 cells with complement C4a treatment.

RESULTS

Significantly altered protein peaks were found through statistical analysis, and m/z 4300 was predicted by databases and successfully matched with the fragment of complement C4a. According to ELISA, serum complement C4a was found to be significantly lower in CHB patients compared with healthy controls (p < 0.001) and the area under receiver operating characteristics curve is 0.78. Furthermore, complement C4a showed lower expression in HepG2.2.5 cells and the secretion of HBV DNA was inhibited by complement C4a.

CONCLUSIONS AND CLINICAL RELEVANCE

The present study implied the important role of complement C4a in inhibiting the HBV DNA secretion in CHB.

Serum complement C4a and its relation to liver fibrosis in children with chronic hepatitis C

AIM: To evaluate serum complement C4a and its relation to liver fibrosis in children with chronic hepatitis C virus (HCV) infection.

METHODS: The study included 30 children with chronic HCV infection before receiving antiviral therapy. Chronic HCV infection was defined by positive anti-HCV, a positive polymerase chain reaction for HCV-RNA for more than 6 mo with absence of any associated liver disease. A second group of 30 age- and sex-matched healthy children served as controls. Serum C4a levels were measured by enzyme-linked immunosorbent assay. Liver fibrosis stage and inflammatory grade were assessed using Ishak scoring system. Serum C4a levels were compared according to different clinical, laboratory and histopathological parameters. Statistical significance for quantitative data was tested by Mann-Whitney U non-parametric tests. For qualitative data, significance between groups was tested by χ² test. Correlation was tested by Spearman’s test. Results were considered significant if P value ≤ 0.05.

RESULTS: The age of the patients ranged from 3.5 to 18 years and that of controls ranged from 4 to 17 years. C4a mean levels were merely lower in patients (153.67 ± 18.69 mg/L) than that in the controls (157.25 ± 11.40 mg/L) with no statistical significance (P = 0.378). It did not differ significantly in patients with elevated vs those with normal transaminases (152.25 ± 16.62 vs 155.36 ± 21.33; P = 0.868) or with different HCV viremia (P = 0.561). Furthermore, there was no statistical significant difference in serum levels between those with no/mild fibrosis and those with moderate fibrosis (154.65 ± 20.59 vs 152.97 ± 17.72; P = 0.786) or minimal and mild activity (155.1 ± 21.93 vs 152.99 ± 17.43; P = 0.809). Though statistically not significant, C4a was highest in fibrosis score 0 (F0), decreasing in F1 and F2 to be the lowest in F3. When comparing significant fibrosis (Ishak score ≥ 3) vs other stages, C4a was significantly lower in F3 compared to other fibrosis scores (143.55 ± 2.33 mg/L vs 155.26 ± 19.64 mg/L; P = 0.047) and at a cutoff value of less than 144.01 mg/L, C4a could discriminate F3 with 76.9% sensitivity and 75% specificity from other stages of fibrosis.

CONCLUSION: Serum complement C4a did not correlate with any of transaminases, HCV viremia or with the histopathological scores. Although C4a decreased with higher stages of fibrosis, this change was not significant enough to predict individual stages of fibrosis. Yet, it could predict significant fibrosis with acceptable clinical performance.