Détermination du type IgM ou IgG des immunoglobulines spécifiques anti-HBc: Relations avec les autres marqueurs du virus HB

Abstract

A procedure for determining anti-HBc of IgM class is described herein. After IgG anti-HBc antibodies have been preferentially absorbed with Staphylococcus aureus cells positive for protein A, we have tested for residual IgM anti-HBc in the supernatant (absorbed serum) by radioimmunoassay. The occurrence and time course of anti-HBc, studied in 3 patients with ongoing infection, show that IgM anti-HBc persist for about 2 months in cases of acute hepatitis. IgM anti-HBc --marker for a recent HBV infection-- was found to be a useful tool in diagnosis of an unapparent hepatitis with transient or undetectable HBs antigenemia (case no 5). The presence of IgM or IgG anti-HBc, HBeAg and anti-HBe was determined by radioimmunoassay in 68 patients HBsAg positive. The immunoglobulin classes (IgM or IgG) of anti-HBc are dependent on the phase of hepatitis B. Of the 29 IgM anti-HBc positive specimens, 28 were found to be HBeAg positive, 18 of these patients were hemodialysed. 62 among 63 HBsAg positive blood donors had IgG anti-HBc, 6 associated with HBeAg and 56 with anti-HBe. All anti-HBc of anti-HBs positive sera were of IgG class (patients or blood donors). In order to estimate the anti-HBc titer, we have determined the per cent inhibition of 134 HBsAg and 46 anti-HBs positive sera diluted to 1 : 100. We correlate the presence of HBsAg --regardless of the level of titer of it --with high titers of anti-HBc and the presence of anti-HBs with low titers (P less than less than 0,0001). These results are very instructive with regard to the problem of anti-HBc titer and possibility of persisting HBV and we support the hypothesis that HBsAg negative but strongly anti-HBc positive blood might be infectious. IgM anti-HBc are on the average of lower titer than IgG anti-HBc, but we did not observe difference in IgG anti-HBc titer between HBeAg positive sera and anti-HBe, HBsAg positive sera.