Postoperative control for the persistence of positivity in three immunological tests used in the diagnosis of hydatidosis in children (E.L.I.S.A.-specific IgE, indirect hemagglutination and E.L.I.S.A.-total IgE).

The persistence of serological positivity was studied in 21 children with surgically proven hydatidosis. The children had been previously operated on between 10 months and 7 4/12 years before serum samples were extracted. Forty-eight people (19 adult and 39 children) were included as a control group. E.L.I.S.A. specific IgE and indirect hemagglutination techniques were used for the diagnosis of hydatid disease. Studies of the immunoglobulins and complement components IgG, IgA, IgM, IgE, C3, C4, C5 and factor B were done on the sera from the 21 children with histories of equinococciasis. The results are expressed according to the location and physical condition of the cyst, the time passed after surgery, the number of cysts and the number of surgical operations. We found persistence of positivity of up to 5 4/12 years for indirect hemagglutination and up to 6 7/12 years for specific IgE, in cases without evidence of clinical parasitation so we think that the postoperative control must be based on several serological determinations. The concordance between the two specific serological tests (specific IgE and indirect hemagglutination) was 80.95%; specific IgE having appeared more sensitive especially in cases of hepatic location. The results concerning the total IgE determination were highlighted in the immunoglobulin studies. We consider total IgE as being only orientative, because of the frequency with which it is found elevated in childhood diseases.