[Observations on the behaviour of anti-HAV antibodies (author's transl)].

The behaviour of anti-HAV antibodies was studied in the following conditions: a) a sample group of 2645 subjects from a healthy population; b) a group of 32 subjects with previous HB-Ag negative viral hepatitis; c) 12 cases of acute virus A hepatitis; d) a group of 18 anti-HAV positive women at the end of their pregnancies the antibodies were thus also studied in the funicular blood and in the newborn babies. The results showed: a) high reactivity (78%) of the healthy population to anti-HAV's; b) the possibility of an a posteriori diagnosis of virus A hepatitis in the presence of serology, negative for B type hepatitis, and positive for the anti-HAV's but with a titre higher than 1:200; c) the possibility of a serological diagnosis of acute virus A hepatitis in the presence of serology, negative for B type hepatitis and positive for the anti-HAV's with high and progressively increasing titre; d) the possibility of anti-HAV antibodies passing from mother to foetus, and the rapid elimination of the antibodies by the newborn baby within a month of his birth.