Contribution of immunoblot to the diagnosis and monitoring of toxoplasmosis in acquired immunodeficiency syndrome]

This study evaluates the potential value of immunoblot for serological survey of toxoplasmosis infection in HIV infected patients. This technique was applied to the detection of IgG, IgM, IgA and IgE antibodies to Toxoplasma gondii in serum and cerebrospinal fluid. We compared the patterns obtained from sera of immunocompetent and HIV+ subjects in different situations: absence of toxoplasmosis, primo-infection, chronic infection and reactivation of toxoplasmosis. IgA antibodies were demonstrated in sera of all HIV+ patients with chronic infection: so, these antibodies have any diagnosis value in this group. IgE were only detected by immunoblot when clinical symptoms of toxoplasmosis occurred in cases of HIV+ patients with reactivation of the parasitosis; previously, these subjects presented a serological rise of IgG specific antibodies. In ten cases of neurotoxoplasmosis immunoblot allowed detection of IgA and IgE antibodies in serum and CSF and demonstrated their intrathecal synthesis in three cases. In conclusion immunoblot is a powerful technique for detection of IgA and IgE to Toxoplasma gondii. Demonstration of IgE antibodies seem to be a good criterion to evaluate the evolutivity of the parasitosis in HIV patients.