Antibody persistence after surgical treatment of echinococcosis.

Studies on the persistence and levels of antibodies in 280 patients at different intervals following surgery for echinococcosis are described. Post-operative antibody levels were investigated by means of four immunodiagnostic methods, namely, the complement fixation, latex agglutination, indirect haemagglutination, and intradermal tests. After surgical removal of the cysts the tests became negative in some patients, whereas in others they remained positive for many years. As the post-operative period increased, the percentage of positive results fell and this fall was faster in lung echinococcosis than in liver echinococcosis. The titres obtained with the serological tests decreased at the same rate as the percentage of positive results, but the intradermal test remained positive, with an unchanged titre, for many years. In the case of secondary echinococcosis, medium and high titres predominated in all the tests. These immunological investigations during the post-operative period make it possible to evaluate the results of surgery and, to some extent, to clarify the prognosis.