Sex-specific Associations between Immune Parameters and Clinical Symptoms in First-episode Patients with Schizophrenia

Introduction: Inflammation is linked to the pathophysiology of schizophrenia. The neutrophil- to-lymphocyte ratio (NLR), a measure of systemic inflammation, has been reported to be associated with schizophrenia. However, few studies have examined the sex-specific association between neutrophil-to-lymphocyte ratio (NLR) and clinical symptoms in schizophrenia. This study aimed to explore sex differences in NLR and its correlation with symptoms in first-episode schizophrenia (FES) patients. Methods: Ninety-seven FES patients and 65 control subjects were recruited. The severity of clinical symptoms was assessed using the Positive and Negative Syndrome Scale (PANSS), and white blood cells were calculated. We performed a cross-sectional analysis comparing NLR in males and females in the patient and control groups. We explored its sex-specific associations with clinical symptoms in the patient group. Results: We found that neutrophil (NEU) counts and NLR were higher in male patients compared to female patients with schizophrenia. There were no significant differences in white blood cell counts and NLR in healthy controls. Linear regression analysis showed that NEU counts were associated with clinical symptoms in male patients, and NLR correlated with symptoms in female patients after controlling for age, onset age, and years of education. Conclusion: Our study suggests that NLR values and NEU counts were higher in male patients compared with female patients with schizophrenia and that the association between NLR or NEU and clinical symptoms was sex-specific.