Specific IgM antibody response, evaluated by micro-ELISA, to various antigen fractions from sheep hydatid fluid and scolices of E. granulosus, in sera from patients affected by hydatid disease, before and after surgery.

Antigen fractions 0.8 M, (1.6-0.8) M and (2.5-1.6) M were prepared from sheep fertile hydatid fluid and scolices of E. granulosus by differential precipitation with ammonium sulphate. The micro-ELISA technique was used to study the specific IgM antibody response towards these six antigen fractions in sera from patients affected by hydatid disease before and after surgery. The results show 0.8 M hydatid fluid antigen to be the most suitable for eliciting a specific IgM response both during the pre-surgery phase and after operation. Furthermore the finding of specific IgM positivity in patients with active hydatidosis raises the suspicion of open or fissured cysts whereas the positivity after operation would seem to be due to the release of antigen by surgical procedures and not prognostic for relapse.