Diagnostic and prognostic significance of IL-18 and its −607C/A polymorphism in COVID-19: Implications for CURB-65 severity scoring

BACKGROUND: Interleukin-18 (IL-18) is a key inflammasome-related cytokine implicated in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. OBJECTIVE: This study investigated the diagnostic, prognostic, and immunogenetic relevance of IL-18 and its promoter polymorphism (-607C/A, rs1946518) in COVID-19 susceptibility, severity, and mortality among Kurdish coronavirus disease-2019 (COVID-19) patients. METHODS: A total of 100 unvaccinated COVID-19 patients and 80 healthy controls (HCs) were enrolled. COVID-19 patients were further classified into non-severe (n=60) and severe cases (n=40), and additionally into survived (n=75) and non-survived groups (n=25). Biochemical markers, CURB-65 scores, and clinical outcomes (severity and survival) were assessed. Genotyping of the IL-18 -607C/A polymorphism was performed using polymerase chain reaction - sequence-specific primer (PCR-SSP). RESULTS: COVID-19 patients exhibited markedly elevated IL-18 levels compared with HCs (509.1 vs. 228.8pg/mL, p