No abstract

This study estimated a 17.3% seroprevalence of HBV and a 4.4% seroprevalence of HCV in Taiwan. Significant geographic variations in the seroprevalence of HBV and HCV were found. These data suggest the importance of modifying programs for the prevention and treatment of chronic viral hepatitis in Taiwan to reflect its varying prevalence and epidemiology.

T cell proliferative responses to hepatitis B virus-encoded envelope antigen (S + preS2 + preSj), recombinant core antigen (HBcAg), and natural hepatitis B e antigen (HBeAg) were examined in 22 HBeAg-positive patients with chronic type B hepatitis and 17 healthy hepatitis B surface antigen (HBsAg) carriers. The results showed that HBeAg-positive patients had (a) higher levels of T cell responses to HBcAg/HBeAg than those of healthy HBsAg carriers (P < 0.001 and P < 0.01, respectively); (b) a further increase in these T cell responses during acute exacerbations (P < 0.05 and P < 0.05, respectively); (c) subsidence in the T cell responses to HBcAg/HBeAg after recovery from acute exacerbations and HBeAg seroconversion, whereas the responses would persist at high levels if the patients did not enter a clinical remission; and (d) low levels of T cell responses to S + preS2 + preS, either before or after HBeAg seroconversion. The appearance of increasing T cell responses to HBcAg/HBeAg usually occurred in the early phase of acute exacerbations. These findings imply that HBcAg/HBeAg-specific T cells play an important role in the exacerbations of chronic hepatitis B and in HBeAg seroconversion. HBcAg/HBeAg-specific precursor T cell frequencies were serially studied in selected cases by limiting dilution assay. Elevation (two-to fourfold) of HBcAg/HBeAg-specific precursor T cell frequencies contributed to the increase of HBcAg/HBeAg-specific T cell proliferation during acute exacerbations. (J. Clin. Invest. 1992.89:87-96.)

To combat hepatitis B virus (HBV) infection in Taiwan, a mass immunoprophylaxis program was launched on July 1, 1984, aiming first at prevention of chronic HBV carriage from perinatal mother-to-infant infection. In the first 15-month period, 352,721 (78%) of 450,585 pregnant women were screened for hepatitis B surface antigen (HBsAg); HBsAg was present in 62,359 (18%), with 50% of them categorized as highly infectious. Infants born to HBsAg-positive women were given 5 micrograms of a plasma-derived hepatitis B vaccine at ages 1, 5, and 9 weeks, with a booster at age 12 months. Infants of highly infectious carrier mothers received an additional 0.5 mL of hepatitis B immune globulin within 24 hours after birth. The coverage rate of the hepatitis B immune globulin was 77% in 27,375 infants born to highly infectious mothers, and that of the first, second, third, and the fourth doses of vaccine was 88%, 86%, 84%, and 71%, respectively, in infants of 55,620 carrier mothers. The reported untoward reactions to immunization were negligible. We conclude that a mass hepatitis B vaccination program is feasible in hyperendemic areas such as Taiwan; this should be a significant step toward the effective control of HBV infection in these areas.

To assess the contribution of hepatitis C virus (HCV) in liver disease in Taiwan, antibody to HCV (anti-HCV) was studied by radioimmunoassay in 392 patients with chronic liver disease and in 440 healthy adults and 444 subjects at risk. The anti-HCV prevalence was 0.95% in 420 volunteer blood donors, 90% in 100 hemophiliacs, and 81% in 58 parenteral drug abusers. Anti-HCV was present in 6 (7.7%) of 78 hepatitis B surface antigen (HBsAg)-positive and 28 (65%) of 43 HBsAg-negative patients with chronic hepatitis, 3 (10%) of 31 HBsAg-positive and 13 (43%) of 30 HBsAg-negative cirrhotics, and 7 (17%) of 42 HBsAg-positive and 15 (63%) of 24 HBsAg-negative patients with hepatocellular carcinoma (HCC). An outbreak of non-A, non-B hepatitis revealed 18% of 57 patients to be positive for anti-HCV, and in 29 patients with posttransfusion hepatitis prospectively followed, 7 (24%) developed anti-HCV. Thus, HCV infection appears to play a relatively minor role in HBsAg-positive liver disease in Taiwan but is strongly associated with HBsAg-negative chronic liver disease and HCC. The infection is extremely common in hemophiliacs and parenteral drug abusers.