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. Beta2-Microglobulin (beta2M) 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 beta2M in antipsychotic-naïve schizophrenia patients (n=43) in comparison with age, sex, handedness and socioeconomic status matched healthy controls (n=43). Serum beta2M was significantly higher in schizophrenia patients (1692.6+/-354.4 ng/mL) than healthy controls (1409.6+/-246.9 ng/mL) (t=4.3; p<0.0001). There was a significant positive correlation between beta2M level and total psychopathology score (r=0.32; p=0.035). These novel observations suggest that beta2M abnormalities might have a potential association with the pathogenesis of schizophrenia.