Serologic evaluation of cytomegalovirus (CMV), Toxoplasma gondii and Brucella in schizophrenia patients

Infectious agents are considered as a possible cause of schizophrenia. The aim of this study was to evaluate the serum levels of cytomegalovirus (CMV), Toxoplasma gondii and Brucella antibodies in schizophrenia patients compared with the control group.

This cross-sectional study was performed on 75 patients with schizophrenia who were clinically diagnosed with schizophrenia using the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) by two independent psychiatrists. As the controls, 75 sex and age-matched individuals were selected from orthopedic and surgical wards, who were admitted because of trauma. Anti-Toxoplasma gondii IgG antibody was detected by Abbott's company diagnostic kit. To detect anti-Brucella IgG antibodies, the enzyme-linked immunosorbent assay (ELISA) test with Vircell diagnostic kit was used. Quantitative luminescence (CLIA) method using Abbott diagnostic kit was also used to detect anti-cytomegalovirus IgG antibody (CMV IgG avidity).

There was not any clinically significant differences in the mean value of Toxoplasma, CMV and Brucella IgG antibodies between schizophrenia and control group. However, considering cut-off point for these tests and further analysis with non-parametric tests showed clinically significant difference between two groups at cut-off point 1.1 for anti-Brucella IgG antibody which indicated more positive samples in schizophrenia group (24 out of 75) than control group (12 out of 75) with a p-value less than 0.05 (0.046).

The results of the present study showed no association between toxoplasmosis infection and CMV and schizophrenia. However, there might be a positive correlation between anti-Brucella IgG antibody and schizophrenia.