CHID1 (chitinase domain containing 1) is a chitinase-like protein with dual roles in immune sensing and inflammatory regulation. As a saccharide- and lipopolysaccharide-binding protein, CHID1 functions in pathogen recognition and endotoxin neutralization, with preference for chitotetraose oligosaccharides. At the molecular level, CHID1 positively regulates RIG-I-like receptor antiviral signaling by enhancing polyubiquitination of RIG-I and VISA, thereby promoting interferon-β production and NF-κB/IRF3 activation during viral infection 1. Clinically, CHID1 expression associates with multiple pathological conditions. In Alzheimer's disease, altered CHID1 brain expression correlates with neuroinflammatory markers including microglia activation (IBA1) and calcium-binding proteins, suggesting involvement in neurodegeneration 2. CHID1 expression appears as a prognostic biomarker in non-small cell lung cancer, with high tumor cell expression correlating with favorable prognosis in adenocarcinoma 3. Genetic variants in the CHID1 locus (11p15.5) associate with chr11 bronchitis in COPD populations 4. Additionally, CHID1 emerges as a hub gene in acute myocardial infarction platelet transcriptomes, linking to calcium-binding and extracellular processes 5. These findings establish CHID1 as a multifunctional immune regulator with emerging diagnostic and therapeutic potential across inflammatory, neurodegenerative, and malignant diseases.