The present study was undertaken to genotype four single nucleotide polymorphisms, which were previously found to be associated with schizophrenia, in 77 patients with schizophrenia and 52 control subjects in order to assess their genotypic association with plasma IL-2 levels. Kruskal-Wallis analysis revealed an association between rs4811528 and plasma IL-2 levels in the patient group (χ(2)=7.60, df=2, p=0.022) but not in the control group; binary logistic regression also confirmed the association of rs4811528 with altered IL-2 secretion (χ(2)=8.191, df=3, p=0.042) after adjustment for age and sex. TGM2 may be involved in dysfunction of the immune system in schizophrenia.