Longitudinal study of the specific humoral and cellular response to Toxoplasma gondii in a patient with acquired toxoplasmosis.

Specific cellular and humoral response to Toxoplasma were evaluated during a 2 yr follow up in a patient with acquired infection. Antibodies were titrated using conventional serological tests and analyzed by western blot technique. Analysis of the patterns obtained with IgA, IgG and IgM antibodies allowed a clear differentiation between acute and chronic stages of infection. Determination of lymphocyte subsets showed an important increase in the number of CD8 suppressive cells at the acute phase whereas CD4 cells remained within the normal range. Lymphocyte proliferation to Toxoplasma antigen was detectable one month after the onset of clinical symptoms and remained constantly positive. These results indicate that western blot analysis of antigens recognized by antibodies and determination of lymphocyte subsets may be helpful in the characterization of the infectious stage of acquired toxoplasmosis.