19. Infectious and inflammatory markers in schizophrenia

A number of infectious and inflammatory markers have been associated with schizophrenia but previous investigations have not yielded definitive conclusions. We examined multiple antibodies to infectious agents and food antigens as well as protein markers of inflammation in well-characterized individuals with a recent onset of psychosis (N = 106), persistent schizophrenia (N = 261), and controls (N = 233). Linear regression methods were used to calculate the association between the markers in both patient groups in comparison with controls adjusting for demographic factors. For the recent onset group, significant associations were found for IgG antibodies to measles (t = 8.31, p < .001), gliadin (t = 5.90, p < .001), bovine casein (t = 4.74, p < .001), human coronavirus (t = 2.89, p = .004), Toxoplasma gondii (t = 2.20, p = .029), and the group D retroviruses, Mason-Pfizer monkey virus (t = 3.97, p < .001) and murine leukemia virus (t = 3.27, p = .001). For the persistent schizophrenia group, significant associations were found for C-reactive protein (t = 7.47, p ⩽ .001); IgG antibodies to wheat gliadin (t = 2.58, p = .010), Saccharomyces cerevisiae (t = −2.78, p < .006), measles (t = 2.37, p = .018), Herpes simplex virus (HSV) type 2 (t = 2.56, p = .011), and human coronavirus (t = 2.67, p = .008). No significant case-control differences were found for antibodies to cytomegalovirus, HSV-1, Epstein-Barr Virus, varicella-zoster virus, or influenza viruses. These results indicate overlap between the markers found in recent onset psychosis and in persistent schizophrenia. Future studies that assess patients throughout the course of the illness may further identify the infectious and inflammatory factors that contribute to disease pathogenesis.