Macrophage-derived CXCL8 as a mediator of inflammatory attacks in Meniere's disease.

BACKGROUND: Ménière's disease (MD) is a complex disorder whose pathogenesis extends beyond endolymphatic hydrops to involve dysregulated immune responses. While a subset of patients exhibits a "low-cytokine phenotype" during remission, the mechanisms underlying the transition to acute inflammatory attacks triggered by environmental factors remain poorly understood. METHODS: We employed an integrative multi-omics approach to explore the immune microenvironment of MD. This included bioinformatic analysis of differentially expressed genes (DEGs) from GSE109558, featuring PBMCs from MD patients and healthy controls stimulated with Aspergillus or Penicillium. Protein-protein interaction (PPI) networks, immune infiltration analysis, and single-cell RNA sequencing (GSE269117) were utilized to identify hub genes and cellular interactions. Key findings were validated in an independent cohort through measurement of serum cytokines, in vitro macrophage stimulation assays, and immunofluorescence staining. RESULTS: Bioinformatic analysis revealed a latent hyperinflammatory potential in MD PBMCs, which was unmasked upon fungal challenge, showing significant enrichment in neutrophil chemotaxis and NF-κB pathways. We identified 20 hub genes, with CXCL8 emerging as a top candidate. Single-cell sequencing and CellChat analysis pinpointed macrophages as the dominant source of CXCL8 and key orchestrators of intercellular communication, notably via the ALCAM-CD6 pathway with T cells. In vitro verification confirmed this macrophage-driven inflammatory cascade response. Under the stimulation of LPS/β -glucan, the level of CXCL8 secreted by macrophages in MD patients increased (p < 0.01), while there was no difference before and after stimulation in the healthy control group. Serum levels of CXCL8, IL-6, and IL-17A were also significantly elevated in MD patients during attacks. CONCLUSION: Our findings support a novel "hypoimmune-hyperinflammatory switch" model in MD, wherein macrophages play an important role in initiating and amplifying inflammatory responses to environmental triggers via CXCL8 production and cellular crosstalk. This refined understanding of the immune axis in MD provides a foundational basis for developing targeted immunomodulatory therapies.