Macrophage migration inhibitory factor as a potential novel biomarker for cognitive function in patients with first-episode schizophrenia

Objective: Cognitive impairment is prevalent in schizophrenia. Macrophage migration inhibitory factor which is released into the circulation under stress or inflammation, is associated with cognition and also plays an important role in immunity. However, no study has investigated the relationship between macrophage migration inhibitory factor and cognitive function in first-episode schizophrenia patients at baseline or after treatment. This study investigated the pre- and post-risperidone treatment correlations between serum macrophage migration inhibitory factor levels and cognitive function in first-episode schizophrenia patients. Methods: A total of 83 first-episode schizophrenia patients who received risperidone monotherapy and 57 healthy controls – matched for sex, age, smoking status, education (years), marital status and waist-to-hip ratio – were included. Macrophage migration inhibitory factor levels were measured before and 10 weeks after treatment in the patient group and at baseline in the controls. Pre- and post-treatment cognitive functions in patients were assessed using the MATRICS Consensus Cognitive Battery. Results: At baseline, macrophage migration inhibitory factor levels were significantly higher in first-episode schizophrenia patients than those in healthy controls ( p < 0.01) and decreased in patients after 10 weeks of risperidone treatment compared with baseline ( p < 0.05). The MATRICS Consensus Cognitive Battery total score and the sub-scores for the Trail Making Test, Symbol Coding, Letter Number Sequence, Maze and Brief Visuospatial Memory Test–Revised improved significantly after risperidone treatment. After controlling for age, sex, education, waist-to-hip ratio and smoking status, partial correlation analysis showed a positive correlation between baseline macrophage migration inhibitory factor levels and patients’ baseline MATRICS Consensus Cognitive Battery verbal memory scores ( r = 0.29, p = 0.01). Macrophage migration inhibitory factor changes correlated negatively with verbal memory changes ( r = −0.26, p = 0.04). Multiple linear regression analysis identified a definite correlation between the changes in word memory test score and macrophage migration inhibitory factor level (β = −0.09, p = 0.04). Conclusion: Macrophage migration inhibitory factor may be involved in the process of cognitive impairment in first-episode schizophrenia and repair mechanisms following risperidone treatment.