45PGRO chemokines-induced neutrophil extracellular trap CITH3 as a new biomarker related to myasthenia gravis severity

The role of innate immunity, particularly neutrophils, remains understudied in Myasthenia Gravis (MG) pathogenesis. To identify novel MG biomarkers through multi-omics screening. We performed eQTL GWAS analysis on 3273 proteins in Caucasian populations (3273 MG patients, 3301 controls), followed by validation in a Chinese Han population using ELISA and Luminex assays. Single-cell and bulk RNA sequencing analyses, flow cytometry, blood smear staining, and immunofluorescence were used to further investigate the ligand-receptor mechanism of candidate biomarkers. Genetically elevated plasma GRO chemokine levels significantly correlated with increased MG risk in Caucasians (p = 5.39e-06). ELISA and Luminex multiplex protein assays confirmed significantly higher plasma GRO chemokines in Chinese Han MG patients than controls (100 patients and 40 healthy controls, p <0.0001). Hemogram analysis and flow cytometry revealed elevated neutrophil counts and CXCR2 (GRO receptor) expression in MG patients (50 patients and 50 controls, p <0.0001). Neutrophil single-cell (n = 6) and whole blood bulk RNA-seq (n = 20) analyses demonstrated prominent CXCR2-induced neutrophil extracellular traps (NETs) in MG, confirmed by blood smear staining and immunofluorescence. ELISA measurements showed elevated plasma CITH3, a major NETs component, in MG patients (49 patients, 73 controls, p <0.0001), which strongly correlated with MG severity scales and GRO levels (r>0.4, p <0.001). CITH3 derived from neutrophil death-induced NETS emerges as a novel potential biomarker for MG severity.