The association between antibodies to neurotropic pathogens and schizophrenia: a case-control study

Abstract

Background:Exposure to neurotropic pathogens has been proposed as an environmental risk factor for schizophrenia and can be evaluated by measuring pathogen-specific immunoglobulin G (IgG). Seroprevalence of pathogen-specific IgG reflects prior exposure, whereas IgG levels are associated with reactivity or reinfection. Several studies have examined these parameters in schizophrenia. However, results still remain inconclusive, as several previous studies did not correct for important confounding factors.Aims:To investigate whether schizophrenia is associated with prior exposure to neurotropic pathogens, or with their reactivation.Methods:We examined the seroprevalence and titer of IgG antibodies against herpes simplex virus-1 and -2 (HSV-1/HSV-2), varicella zoster virus (VZV), Epstein–Barr virus (EBV), cytomegalovirus (CMV), and Toxoplasma gondii (TG) in plasma of 368 adult patients with a schizophrenia spectrum disorder and 282 controls using ELISA.Results:We did not find evidence for an increased exposure to HSV-1, HSV-2, EBV, and TG in patients. There was a significantly higher seroprevalence of VZV (98.9% vs. 95.6%, P<0.05) and CMV (40.4% vs. 27.7%, P<0.001) in controls as compared with patients, which did not remain statistically significant after adjustment for various potential confounders. We did not find significant differences in antibody titers of seropositive patients and controls for any of the six pathogens.Conclusions:Our results do not support the hypothesis that increased exposure to neurotropic pathogens after birth is associated with schizophrenia.

Schizophrenia is Associated With an Aberrant Immune Response to Epstein–Barr Virus

“…It is thus of interest that DeWitte et al did not find an association between levels of antibodies to EBV and a schizophrenia diagnosis. 34 However, as they measured EBNA antibodies (DeWitte L, personal communication) as markers of EBV exposure, their findings are consistent with ours. The consistency of our results with other studies that have measured EBV antibodies in individuals with schizophrenia [35][36][37] is difficult to evaluate without additional information relating to the immune responses to defined EBV proteins.…”

Association of Toxoplasma gondii infection with schizophrenia and its relationship with suicide attempts in these patients

“…Previous studies from Iran arrived at inconsistent results regarding the association between schizophrenia and T. gondii seropositivity . Recent research from other countries failed to show a significant association between schizophrenia and T. gondii infection .…”

“… of 38 studies showed that individuals with schizophrenia have an increased prevalence of antibodies to T. gondii ; the overall odds ratio was 2.71 (95% CI: 1.93–3.80). However, other studies failed to demonstrate a significant association between schizophrenia and toxoplasmosis . Several investigators in various parts of Iran have sought to determine the association of schizophrenia with T. gondii seroprevalence.…”

Early Senescence and Leukocyte Telomere Shortening in SCHIZOPHRENIA: A Role for Cytomegalovirus Infection?

“…Results from other groups also support that the increase in antibody levels to several viruses is predictive of an 18–34% increase in the risk of developing schizophrenia [ 122 ] or that anti-CMV and anti-HSV1 antibody levels are significantly increased in schizophrenia patients [ 123 ]. However, others have not found significant differences in antibody titers against the pathogens studied, and therefore do not support the hypothesis that increased exposure to neurotropic pathogens after birth is associated with schizophrenia [ 124 , 125 ]. Other evidences demonstrate that CMV infection is associated to poorer markers in the evolution of schizophrenia.…”