The specific immunoglobulin in hydatid disease.

The variation in the serum level of specific IgG, IgM and IgA antibodies during different stages of hydatid disease has been demonstrated by a technique of fluorescent microscopy that uses monospecific anti-human immunoglobulin conjugates and freeze-dried antigens. The technique is easy to perform and our results suggest that the test is sensitive and specific. Specific IgG antibodies are present in patients with either current or past infections. IgM antibodies, detected during periods of antigenic activity, disappear soon after removal of the cyst. In many cases IgA antibodies also disappear soon after removal of the cyst. Cross-reactions between the antigens and antibodies of hydatid disease and schistosomiasis are shown to be present mainly in the IgG immunoglobulin and only to a much smaller extent in the IgA.