Genetic polymorphism of cytokines IL-1β, IL-4 and TNF-α as a factor modifying the impact of childhood adversity on schizophrenia symptoms

Abstract

Based on the hypothesis that activation of the immune system is one of the mechanisms of influence of early environmental factors on the onset and course of schizophrenia, we investigated the effects of the interaction of childhood adversity and IL-1β rs16944, IL-4 rs2243250 and TNF-α rs1800629 polymorphisms on schizophrenia symptomatology. The sample consisted of 546 patients with schizophrenia spectrum disorders. The presence of childhood adversity was determined based on the analysis of medical records and a questionnaire completed by the patient. We used the 5-factor model of the Positive and Negative Syndrome Scale (PANSS) with the nested two-factor negative syndrome model. After adjusting for multiple comparisons, a significant effect of the interaction of childhood adversity and TNF-α on the cognitive/disorganization factor was found, with a difference between genotypes in the group without childhood adversity (pFDR <0.018; η2p=0.03). A significant effect of the interaction of childhood adversity and genotype on the cognitive disorganization syndrome was established (F=5.87; p=0.003; η2p=0.03). Stereotyped thinking and avolition on PANSS had the highest correlations with cognitive disorganization factor (ro=0.84 and ro=0.82, respectively) and the highest significance of differences depending on the interaction of genotype and childhood adversity (Kruskal-Wallis test, H=12.28, p=0.006 and H=12.79, p=0.005, respectively). Childhood adversity modifies the relationship between the pathogenesis of schizophrenia and the TNF-α promoter polymorphism rs1800629, which is also an enhancer of another 60 genes located in the major histocompatibility complex.