Studies examining immune dysfunction in schizophrenia have reported decreased type-1 T-helper cell specific immunity (Th1) and increased type-2 T-helper cell specific immunity (Th2) and related abnormalities in inflammatory system. β2-Microglobulin (β2M) influences the development of dendritic cells, which play a significant role in regulating the differentiation of naive CD4 + T cells into Th1 or Th2 lineages. The present study examined serum β2M in antipsychotic-naïve schizophrenia patients (n=43) in comparison with age, sex, handedness and socioeconomic status matched healthy controls (n=43). Serum β2M was significantly higher in schizophrenia patients (1692.6±354.4ng/mL) than healthy controls (1409.6±246.9ng/mL) (t=4.3; p<0.0001). There was a significant positive correlation between β2M level and total psychopathology score (r=0.32; p=0.035). These novel observations suggest that β2M abnormalities might have a potential association with the pathogenesis of schizophrenia.