RESUMEN
BACKGROUND AND OBJECTIVE: Toxoplasma gondii is an obligate intracellular protozoan parasite widely distributed all over the world. It has been associated with various psychiatric conditions as schizophrenia. This study aiming to evaluate the association between T. gondii infection and schizophrenia and to estimate the effect of T. gondii infection on the serum dopamine level among schizophrenic patients. MATERIALS AND METHODS: A case-control study was conducted over 45 schizophrenic patients and 44 normal controls. Serum IgM and IgG anti-T. gondii antibodies were detected by a commercial ELISA Kit. The immunoblotting method was performed for the detection of IgG anti-Toxoplasma dopamine was detected by the human dopamine ELISA kit. RESULTS: Anti-T. gondii IgM was negative in all the 90 studied individuals. However, anti-T. gondii IgG was positive in 25 schizophrenic patients (55.6%) and 13 normal healthy controls (28.9%). Immunoblotting showed stronger specific reaction to proteins with molecular weights 50 and 60 kDa by +ve IgG schizophrenic patients. The serum dopamine level among schizophrenic patients was increased as compared to healthy controls (47.22 and 25.79%, respectively; p <0.001). In addition, the dopamine levels in +ve IgG were higher than those of -ve IgG schizophrenic patients. CONCLUSION: These results suggest that chronic T. gondii infection causes high dopamine levels that may lead to schizophrenia. About 55% of schizophrenic patients showed positive IgG reactions to Toxoplasma within this population, the dopamine levels were higher than seronegative population and revealed both 50 and 60 kDa proteins band specific to Toxoplasma.
