The Role of Cytokines in the Immunopathogenesis of Toxoplasmosis

Objective: Infection caused by the obligatory intracellular parasite Toxoplasma gondii is generally asymptomatic in immunocompetent individuals but may be life-threatening in immunosuppressed patients and congenitally infected fetus. Scientists believed that the pathogenesis of the infection could be well established if the relation between cellular and humoral immune response was documented. Material and Methods: Starting from this point we tried to establish this relation, by measuring the production of Interferon-gamma (IFN-gamma) (T(h)1 cytokine) and interleucine (IL)-5 (T(h)2 cytokine) in supernatants of peripheral blood mononuclear cells (PBMC) after in vitro specific T gondii antigen stimulation in 19 patients that were grouped according to their anti-Toxoplasma IgM and IgG levels. Results: In our study, we observed that the level of IL-5 synthesis was higher than IFN-gamma in the initial phase of the infection; as the specific IgG titers started to rise, IFN-gamma synthesis increased and suppressed the synthesis of IL-5. As the infection became chronic a de, crease in the IFN-gamma synthesis and a slight increase in IL-5 synthesis were noted. In our seronegative patient group, cytokine production pattern showed mainly T(h)0 subgroup profile. Conclusion: As a result, we suggest that evaluation of antigen specific cytokine synthesis parallel to humoral response in the different stages of toxoplasmosis would be beneficial both in the diagnosis and in follow-up