Quantitative analysis of anti–hepatitis C virus antibody–secreting B cells in patients with chronic hepatitis C

✍ Scribed by Takeji Umemura; Richard Y.-H. Wang; Cathy Schechterly; J. Wai-Kuo Shih; Kendo Kiyosawa; Harvey J. Alter

• Publisher: John Wiley and Sons
• Year: 2005
• Tongue: English
• Weight: 356 KB
• Volume: 43
• Category: Article
• ISSN: 0270-9139
• DOI: 10.1002/hep.20917

✦ Synopsis

To investigate the quantitative characteristics of humoral immunity in patients with hepatitis C, we established an enzyme-linked immunosorbent spot (ELISpot) assay for detection of anti-hepatitis C virus (HCV)-secreting B cells. Receiver operating characteristic curve analysis demonstrated 100% specificity and 58% to 92% sensitivity for detecting B-cell responses to NS5b, NS3, E2, and core antigens. The median sum of anti-HCV-secreting B cells to all HCV antigens tested was significantly higher in 39 patients with chronic hepatitis C (47.3 spot forming cells [SFCs]/10 6 peripheral blood mononuclear cells [PBMCs]) than in 9 recovered subjects (15.3 SFCs/10 6 PBMCs; P ‫؍‬ .05) or 11 uninfected controls (5.3 SFCs/10 6 PBMCs; P < .001); the significant difference (P ‫؍‬ .018) in chronic versus recovered patients was in reactivity to nonstructural antigens NS3 and NS5b. Anti-HCV immunoglubulin M (IgM)-secreting B cells were also readily detected and persisted decades into HCV infection; there was no difference in IgM-positive cells between chronic and recovered patients. ELISpot reactivity to genotype 1-derived antigens was equivalent in patients of genotypes 1, 2, and 3. There was significant correlation between the numbers of anti-HCV IgG-secreting B cells and serum aminotransferase and to the level of circulating antibody. In conclusion, ELISpot assays can be adapted to study B-cell as well as T-cell responses to HCV. Measurement at the single-cell level suggests that humoral immunity plays a minor role in recovery from HCV infection and that B-cell immunity is strongest in those with persistent infection. (HEPATOLOGY 2006;43:91-99.