Prevalence of Antibody to Hepatitis E Virus among Haemodialysis Patients in Taiwan: Possible Infection by Blood Transfusion

BACKGROUND/AIMS

A higher prevalence of anti-hepatitis E virus (HEV) in non-endemic viral hepatitis such as in Germany has been reported in our previous study. The aim of this study was to assess the seroepidemiology of HEV among haemodialysis (HD) patients in Shin-Kong Hospital, Taiwan, and to evaluate whether there was an increased risk of infection and exposure to HEV even in an area of endemic viral hepatitis.

METHODS

Serum samples obtained from 400 Taiwanese patients on chronic HD (group 1), 400 sex- and age-matched healthy subjects (group 2) and hospital patients (group 3) were tested for the IgG anti-HEV.

RESULTS

The prevalence of anti-HEV among the HD patients and the healthy controls were 31 and 8.9%, respectively. The difference (22%) was statistically significant (p < 0.01). In comparison, the anti-HEV in hospital patients was 16%.

CONCLUSION

The study indicated a significantly higher risk of HEV infection among patients on chronic HD in endemic regions of viral hepatitis such as Taiwan. Mostly because of anaemia, HD patients usually received packed transfusion (red blood cells) if their haemoglobin was low. It is possible that HEV infection may be transmitted through blood transfusions in an endemic area. In such areas, appropriate strategies should be adopted to prevent the risk of HEV among HD patients.

Immune response to hepatitis A virus capsid proteins after infection

This study was undertaken to determine the immune response of humans to viral capsid polypeptides of hepatitis A virus (HAV) after natural infection, which is very important for vaccine development. Antiviral capsids in 73 serum samples from patients with acute and chronic HAV infections were analyzed by immunoblotting against individual HAV capsid polypeptides (VP1, VP2, VP3, and VP4) by using a cell culture-based HAV antigen. For reference, total anti-HAV immunoglobulin G (IgG) and anti-HAV IgM were also determined by radioimmunoassay. As a result, a dominant immune response against VP1 (98% IgG, 94% IgM) was found in the acute phase. However, many other sera also reacted with VP0 (88% IgG; 35% IgM) and VP3 (81% IgG and 29% IgM). In contrast to the acute phase, anti-VP1, anti-VP0, and anti-VP3, IgG antibodies against all three viral proteins (29, 29, and 73% respectively), especially those against VP3, were found years after onset of HAV disease and over long periods in the sera of hepatitis patients. These results suggest that antibodies for capsid polypeptides are present over an extended period in the sera of HAV-infected patients. They are likely of importance in maintaining long-term immunity.

Antigenicity of hepatitis A virus after ultra-violet inactivation

Ultra-violet (UV) treatment has been shown to inactivate hepatitis A virus (HAV) in wastewater and polluted drinking water. Whether this method could be used to inactivate virus preparations made for vaccine purposes is not known since the effect of UV on the antigenicity of HAV has not been studied. HAV vaccine preparations have been treated effectively with formaldehyde. However, this method is time-consuming, since treatment times of up to 15 days have been published as necessary for a complete and safe inactivation. We used a cell-culture-derived HAV preparation with a TCID50 of 10(9) for a UV irradiation experiment. The antigenicity (assessed by a panel of anti-HAV antibodies), viral genome titre (quantitated by polymerase chain reaction) and HAV infectivity were compared after treatment with UV doses of 0, 184, 368, 552, 736 and 920 J m-2. Our results showed the antigenicity of HAV was almost unaltered even when infectious viral particles were no longer detectable. This technique shows potential as a simple and low-cost method for an inactivated HAV vaccine.

Affinity capture-polymerase chain reaction for quantitation of hepatitis B virus DNA

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