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A staphylococcus aureus protein A co-operated ELISA (SPA-ELISA) for the detection of anti-HCV-IgM has been established using HCV antigenic polypeptide, SPA-bearing germs and horseradish peroxidase labelled anti-human IgM. The specificity of SPA-ELISA has been confirmed by some substitution tests, blocking tests and destroying test with 2-mercaptoethanol. The results showed that the rate of anti-HCV-IgG in a group of patients with acute hepatitis and there were significant difference in anti-HCV-IgM was higher than that of anti-HCV-IgM detected rates between patients with acute hepatitis and those with chronic hepatitis (32.26%, P < 0.01). On the other hand, the positive rates of anti-HCV-IgM were 53.66% and 63.41% in transfusion associated hepatitis, 38.10% and 42.86% in sporadic hepatitis, 6.11% and 16.33% in people who have had active social activities, 40.00% and 10.00% in a group of blood donors respectively. Furthermore, taking into account the characteristics of HCV polypeptide used, its easiness of manipulation, and elimination of the interference of anti-HCV-IgG in sera, the new SPA-ELISA is believed to be of practical value in clinical and epidemiological studies of hepatitis C.

2346 liver samples from 17 areas in China were investigated for intrahepatic hepatitis D antigen (HDAg) by direct enzyme-labelled technique. HDAg was detected in 167 out of 1764 samples of HBsAg positive individuals with the detection rate of 9.47%. Hepatitis D virus (HDV) infection existed in all the examined areas without any significant difference regarding HDAg detection rate. A relationship of intrahepatic HDAg to the pathologic type of the liver disease was observed. The HDAg detection rate in chronic liver diseases and severe hepatitis was higher than in other liver diseases. It suggested that HDV infection was associated with the progression and chronicity of the liver disease. Studies on the relationship between HDV infection and HBV replication showed that HBV replication might be suppressed by HDV infection. Both HDV and HBV, however, could replicate in the same hepatocyte simultaneously.

28 cases of hemophilia were examined for HCV infection status by using the Kehua anti-HCV ELISA kit of second generation. It was found that the infection rate was 78.5% and the infection rate was even higher with patients who had received transfusions or preparations of coagulatory factors. 10 families of 15 patients were also investigated. It was found that of 15 hemophilia patients, 12 showed positive anti-HCV, while none of their 53 family members exhibited any positive anti-HCV. In 8 children of 9 couples no positive anti-HCV was found. Our results revealed that the hemophilia patient may get infected with HCV by receiving multiple transfusions or preparation of coagulatory factors. The risk of getting infected with HCV via daily-life contact including sexual contact is extremely low.

A biotin-labeled DNA probe specific for hepatitis B virus (HBV) nucleotide sequences was hybridized in situ to liver tissue of 129 cases with liver disease. It was found that HBV DNA was predominantly visualized in cytoplasm of hepatocytes in three patterns: cytoplasmic compact, discrete and inclusion pattern. Its distribution in parenchyma in the sections of specimens may be defined as lobular, focal and spotty. The detection of intrahepatic HBV DNA depended on two factors, at least in the present study: 1) liver disease activity; chronic active hepatitis (CAH) group had a significant higher prevalence (81%) as compared to cirrhosis, chronic lobular hepatitis (CLH), acute hepatitis and hepatocellular carcinoma (HCC) groups; 2) HBV infection state: HBV DNA was more easily detected in HBeAg positive or intrahepatic HBcAg positive patients than in single HBsAg positive or anti-HBc cases. The findings that hepatocytes expressing HBV DNA, particularly in focal distribution, were closely related to hepatic necrosis sites suggested that HBV replication might occur in conjunction with hepatic necrosis.

SDS-polyacrylamide gel electrophoresis and Western blotting analysis by using 9 clones of monoclonal antibodies specific for hemorrhagic fever with renal syndrome (HFRS) viruses were carried out on the virion proteins of 17 strains of HFRS viruses isolated from different areas in Asia and different hosts such as Apodemus agrarius, Rattus norvegicus, domestic cat and HFRS patients. Polypeptide with apparent molecular weight about 50 kitodalton (Kd) could be detected in all 17 strains of HFRS viruses. On this polypeptide there are two different antigenic determinants and one of them might be genus specific.