[Early diagnosis and surveillance of congenital toxoplasmosis. The comparative immunological profiles method]

Abstract

More than 8000 samples (sera, cord blood, CSF, etc.) from patients who had, or were likely to have, toxoplasmosis were studied by the CIP-ELIFA technique. The first stage in this technique is immunoelectrodiffusion on a microporous cellulose acetate membrane. In the second stage, immunodetection and isotypic characterization of the precipitating systems are rapidly carried out by immunofiltration with anti-IgG, IgM, IgA or IgE-labelled antibodies (enzyme-linked immunofiltration assay or ELIFA). Several samples are jointly laid out on the same membrane for compared immunological profiles (CIP). When applied to the mother-foetus relationship in toxoplasmosis, this procedure provides an early diagnosis of congenital infestation in 85% of the cases. Positive criteria are based on evidence of specific IgM, IgE or IgA in the child, but also on the detection of foetal or neonatal antitoxoplasmosis IgG which can be distinguished from the IgG transmitted by the mother. Polyisotypic supervision is of considerable value for assessment of prognosis and of therapeutic effectiveness at the end of treatment. Satisfactory isotypic characterization can only be achieved by using particular functional antigens.