Associations of serum TNF-α, IL-8, and IL-18 levels with the clinical symptoms in acute schizophrenia: a cross-sectional study.

BACKGROUND: Inflammatory responses may play a significant role in the pathophysiology of schizophrenia, but the relationship of inflammatory cytokines with clinical symptoms of acute patients remains incompletely understood. This study aimed to investigate serum levels of tumor necrosis factor-α (TNF-α), interleukin (IL)-8, and IL-18 and the potential association with clinical symptoms of acute schizophrenia patients. METHODS: The cohort of the cross-sectional study included 71 acute schizophrenia patients (medication-free ≥ 4 weeks) and 55 healthy controls. Clinical symptoms were assessed using the five-factor Positive and Negative Syndrome Scale (PANSS). Serum TNF-α, IL-8, and IL-18 levels were measured using Luminex liquid suspension chip assay technology. RESULTS: As compared to healthy controls, acute schizophrenia patients exhibited significantly higher serum levels of TNF-α and IL-8 (both, p < 0.001), while IL-18 levels were significantly lower (p < 0.001). After controlling for confounding factors, serum levels of TNF-α (β = 0.368, p = 0.003) and IL-8 (β = 0.414, p = 0.001) were positively correlated with the PANSS anxiety/depression factor. TNF-α was positively correlated with IL-8 (r = 0.334, p = 0.004) and IL-18 (r = 0.301, p = 0.011). Sex did not modulate the relationship between IL-8 and anxiety/depression symptoms (p = 0.572). Additionally, IL-18 was positively correlated with body mass index (r = 0.295, p = 0.019) and sex (r = 0.384, p = 0.001), while the excitement/hostility factor was positively correlated with age of disease onset (r = 0.293, p = 0.013). CONCLUSION: These findings support the involvement of inflammatory processes in the pathophysiology of acute schizophrenia, particularly the association of TNF-α and IL-8 with anxiety/depression symptoms. CLINICAL TRIAL NUMBER: Not applicable.