Elevated serum S100B protein in first-episode drug-naive Chinese patients with schizophrenia

Mounting evidence suggest that astrocytes might be involved in the pathogenesis of schizophrenia. Of particular interest is S100B, a protein produced primarily by astrocytes that plays a critical role in the maintenance of functional neuronal and astroglial activation. Abnormalities in S100B levels have been associated with schizophrenia. In this study, we examined serum S100B protein levels and the relationship between S100B levels and psychopathological symptoms in first-episode, drug-naïve patients with schizophrenia (SCZ). Sixty-four patients with schizophrenia were compared with 66 age- and sex-matched healthy controls (HC). Psychopathology in the SCZ group was assessed by the Positive and Negative Syndrome Scale (PANSS). Serum S100B protein levels were measured by sandwich enzyme-linked immunosorbent assay (ELISA). The results showed that S100B protein-like immunoreactivity was significantly higher in the SCZ group than the HC group. S100B-like immunoreactivity was correlated with age, duration of illness, and PANSS subscale scores for negative and general psychopathology and total scores. In the SCZ group, serum S100B levels in residual-subtypes were significantly higher than in the paranoid- and disorganized-subtypes. Our findings suggest an upregulation of a marker for astrocyte activity, i.e., S100B, in first-episode medication-free patients with schizophrenia, and thus support the involvement of astrocytes in the pathogenesis of schizophrenia.