Journal of International Psychiatry

Objective To investigate the significance of CD4+CD25+Foxp3+ regulatory T cells (Treg) and the related inflammatory factors in patients with schizophrenia without first medication. Methods 41 patients with first-stage schizophrenia admitted to Qingdao Mental Health Center from May 2021 to October 2021 were selected as the study group, and 43 healthy workers in our hospital were selected as the control group during the same period. The percentage of CD4+CD25+Foxp3+ Treg cells and the mRNA expression of transforming growth factor-β (TGF-β) and fork-head transcription factor p3(Foxp3) in peripheral blood of the two groups were detected by flow cytometry. Serum levels of interleukin-6 (IL-6) and interleukin-35 (IL-35) were determined by enzyme-linked immunosorbent assay (ELISA). The correlation between the percentage of CD4+CD25+Foxp3+Treg cells and TGF-β, Foxp3, IL-6 and IL-35 levels were analyzed, as well as the correlation with the positive and negative symptom scale (PANSS). Results The percentage of CD4+CD25+Foxp3+Treg cells, the expression of FoxP3 mRNA and the level of serum IL-35 in peripheral blood of patients with first-onset schizophrenia were significantly lower than the control group, while the expression of TGF-β mRNA and the level of IL-6 in peripheral blood were significantly higher than the control group，with statistical significance (P<0.05). The percentage of CD4+CD25+Foxp3+Treg cells in peripheral blood of patients with schizophrenia was positively correlated with peripheral blood Foxp3 mRNA level (r=0.913) and serum IL-6 level (r=0.771) (P< 0.05). And TGF-β mRNA level (r=-0.952), IL-35 (r=-0.908) in peripheral blood were negatively correlated (P < 0.05). The percentage of CD4+CD25+Foxp3+Treg cells in peripheral blood of patients with schizophrenia was negatively correlated with the total score of PANSS and all dimensions (P < 0.05). Conclusion The expression of CD4+CD25+Foxp3+ Treg cells and related inflammatory factors in peripheral blood of patients with schizophrenia, and there is a certain correlation with the severity of the disease, which may be related to the weakened immunosuppressive function in patients. Abnormal cellular immunity regulated by peripheral CD4+CD25+FOXP3+ Treg cells is one of the neuroimmunological mechanisms of schizophrenia.

Schizophrenia; CD4+CD25+Foxp3+Treg cells; TGF-β; Foxp3; IL-6; IL-35