Inadequacy of immunoglobulin M hepatitis B core antibody in detecting acute hepatitis B virus infection in infants of HBsAg carrier mothers

Higher cut-off index value of immunoglobulin M antibody to hepatitis B core antigen in Taiwanese patients with hepatitis B

BACKGROUND

The cut-off index value of immunoglobulin M (IgM) antibody to hepatitis B core antigen (anti-HBc; AxSYM CORE-M, Abbott) for diagnosing acute hepatitis B is 1.2. A high false-positive rate of IgM anti-HBc was observed in acute flare-ups of chronic hepatitis B in Taiwanese patients. Thus the purpose of the present paper was to study the optimal index value of IgM anti-HBc in Taiwanese subjects.

METHODS

The peak index values of 42 IgM anti-HBc-positive patients were collected. There were 20 acute hepatitis B patients and 22 patients with chronic hepatitis B with acute flare. The biochemical, virological, and serological data were obtained.

RESULTS

There were significant differences in mean age (36 vs 47 years, P = 0.01), serum alanine aminotransferase level (2042 U/L vs 1193 U/L, P = 0.02) and peak index value of IgM anti-HBc (2.9 vs 1.5, P < 0.01) between patients with acute hepatitis B and those with acute flare of chronic hepatitis B. Eleven (50%) of 22 patients with chronic hepatitis B with acute flare had index value of >1.2. The optimal cut-off index value to differentiate acute hepatitis B from chronic hepatitis B with acute flare was 2.4-2.5, with a sensitivity of 90% and specificity of 90%.

CONCLUSIONS

The cut-off index value of IgM anti-HBc to differentiate acute hepatitis B from chronic hepatitis B with acute flare among Taiwanese patients should be set at 2.4-2.5 instead of 0.8-1.2.

Epidemiological patterns of hepatitis B virus (HBV) in highly endemic areas

This paper uses meta-analysis of published data and a deterministic mathematical model of hepatitis B virus (HBV) transmission to describe the patterns of HBV infection in high endemicity areas. We describe the association between the prevalence of carriers and a simple measure of the rate of infection, the age at which half the population have been infected (A50), and assess the contribution of horizontal and perinatal transmission to this association. We found that the two main hyper-endemic areas of sub-Saharan Africa and east Asia have similar prevalences of carriers and values of A50, and that there is a negative nonlinear relationship between A50 and the prevalence of carriers in high endemicity areas (Spearman's Rank, P = 0.0086). We quantified the risk of perinatal transmission and the age-dependent of infection to allow a comparison between the main hyper-endemic areas. East Asia was found to have higher prevalences of HBeAg positive mothers and a greater risk of perinatal transmission from HBeAg positive mothers than sub-Saharan Africa, though the differences were not statistically significant. However, the two areas have similar magnitudes and age-dependent rates of horizontal transmission. Results of a simple compartmental model suggest that similar rates of horizontal transmission are sufficient to generate the similar patterns between A50 and the prevalences of carriers. Interrupting horizontal transmission by mass immunization is expected to have a significant, nonlinear impact on the rate of acquisition of new carriers.

Long-term follow-up of hepatitis B virus carrier infants

One hundred twenty-two hepatitis B surface antigen (HBsAg) carrier infants were followed-up for 8-10 years. One hundred eleven had antibody to hepatitis B core antigen (anti-HBc; 83 had been vaccinated) and the remaining 11 were without anti-HBc (7 had been vaccinated). During the follow-up period, 29 (26.1%) carrier infants with anti-HBc had one or more episodes of alanine aminotransferase (ALT) elevation and up to 32.8% (21/64) of the carriers in this group lost their hepatitis B e antigen (HBeAg) before the age of 10. In addition, 2 (1.8%) carriers lost their HBsAg at the age of 3 and 8, respectively. No significant symptom or sign was noted during HBeAg seroconversion. In contrast, all the carrier infants without anti-HBc were still positive for both HBeAg and hepatitis B virus (HBV) DNA and none displayed abnormal ALT levels or any symptom related to liver disease. One became anti-HBc positive at the age of 9, and 5 other carriers had inconsistent borderline or weakly positive titers of anti-HBc. The episodes of ALT elevation and the prevalence of HBeAg seroconversion were not significantly different between immunized carrier infants. In conclusion, HBeAg seroconversion may occur in about one third of the anti-HBc-positive carrier infants during the first decade. On the other hand, the anti-HBc-negative HBsAg carrier infants' immune incompetence to the HBV antigens could persist for more than 10 years. Hepatitis B immunization did not have significant effect on the clinical course in carriers.

Absence or delayed appearance of hepatitis B core antibody in chronic hepatitis B surface antigen carrier children

An absence of the hepatitis B core antibody (anti-HBc) in hepatitis B surface antigen (HBsAg) carrier children has been reported before, but whether anti-HBc will ultimately appear is unknown. In a group of 420 HBsAg carrier children who were followed longitudinally, 10 (2.4%) had an absence or delayed appearance of serum anti-HBc. These 10 children were persistently seropositive for HBsAg, hepatitis B e-antigen, and hepatitis B virus DNA (HBV-DNA). Anti-HBc never appeared in 4, one of whom was a case of hepatitis B vaccine failure and became an HBsAg carrier. Three of the 4 were born to HBsAg carrier mothers. Liver biopsy in one revealed non-specific reactive hepatitis (NSRH). All 4 were asymptomatic during follow-up. Mothers of the other 6 children who had delayed appearance of anti-HBc were also HBsAg carriers. The children seroconverted to anti-HBc positivity between 2 and 8 years of age, and the titer of serum anti-HBc at the first appearance varied. There were no significant changes in liver function tests, HBV-DNA levels, or associated symptoms and signs before and after seroconversion. Liver biopsies were performed before anti-HBc seroconversion in 2 children and showed NSRH. All 10 children had a moderate to high replication of HBV as shown by the high titer of HBsAg and HBV-DNA. The absence of anti-HBc occurred almost exclusively in children who were infected perinatally.(ABSTRACT TRUNCATED AT 250 WORDS)

A prospective study of posttransfusion hepatitis in Taiwan

In a follow-up study of 6 months or more of two hundred and ninety-six patients who had received blood transfusion, 37 (12.5%) developed acute posttransfusion hepatitis. Patients with posttransfusion hepatitis had significantly higher donor numbers and transfusion amounts than patients without hepatitis. Frequency was not related to the age, sex or hepatitis B carriage of recipients. There were no cases of fulminant hepatitis. Of 37 patients with hepatitis, 36 were diagnosed as non-A, non-B hepatitis and one as hepatitis B. Twenty-two (59.5%) of the 36 patients with non-A, non-B hepatitis seroconverted to hepatitis C antibody. Two of these were positive for hepatitis C antibody before transfusion and 12 were negative for hepatitis C antibody. Thirty-three of the 36 patients were followed-up for more than 6 months after the onset of hepatitis. While 13 of the 33 patients recovered, the remaining 20 (60.6%) patients still had persistent liver test abnormalities 6 months after the onset of hepatitis. Seventeen (85%) of the 20 patients who developed chronic hepatitis were hepatitis C antibody positive. In contrast, only four (30%) of the 13 patients who recovered after acute hepatitis were positive for the hepatitis C antibody. Chronicity rate was not related to the patient's sex, age, transfusion amount or donor number. Our results suggest a high frequency of posttransfusion hepatitis C in Taiwan and that the infection has a high risk of chronicity.

Significance of maternal and infant serum antibodies to hepatitis B core antigen in hepatitis B virus infection of infancy

The significance of IgM and IgG class antibodies to hepatitis B virus (HBV) core component (anti-HBc) was investigated in a study of maternal-fetal HBV transmission. An IgM anti-HBc response was lacking in the majority (49/53) of HBV-infected infants. This antibody thus cannot be used as an indicator of transplacental infection. However, most infants who became HBsAg positive during the first 6 months of life acquire infection in the perinatal period rather than transplacentally. Passively transferred maternal IgG anti-HBc in the infant and additional IgM anti-HBc positively in the carrier mother have no modulating influence on HBV infection of infants born to HBV carrier women.

Transplacental leakage of HBeAg-positive maternal blood as the most likely route in causing intrauterine infection with hepatitis B virus

Thirty-two HBeAg-positive carrier mothers and their 32 babies were investigated to elucidate the mechanism involved in intrauterine infection with HBV. Five mothers had symptoms and signs of threatened abortion and/or threatened preterm labor. Three mothers gave birth more than 6 weeks after the episodes, and their babies were those infected in utero. The other two gave birth within 1 week after the episodes, and the two babies were treated with HBIG immediately after birth; HBV infection was successfully prevented. Therefore we suggest that transplacental leakage of HBeAg-positive maternal blood, which is induced by uterine contractions during pregnancy and the disruption of placental barriers, is the most likely route to cause HBV intrauterine infection.

Fulminant hepatitis in children in Taiwan: the important role of hepatitis B virus

In a recent period of 64 months, fulminant hepatitis was diagnosed in 17 children at National Taiwan University Hospital. Eleven patients were younger than 12 months of age. Hepatitis A IgM antibody and delta-antibody were negative in all 17. Eleven (65%) patients had hepatitis B core IgM antibody, fulminant hepatitis B. Two to 5 months before onset of hepatitis. Five of the 11 children had received blood transfusions. Three of the five donors had hepatitis B e antibody (anti-HBe) and were hepatitis B virus DNA-negative hepatitis B surface antigen (HBsAg) carriers; another two were HBsAg negative, screened by a less sensitive reverse passive hemagglutination method. The mothers of all six infants younger than 6 months of age had HBsAg. HBe antigen and antibody were studied in five of these six mothers; all five had anti-HBe. We conclude that hepatitis B virus is the most important cause of fulminant hepatitis in children in Taiwan.