CSF2RB (CD131) is a cell surface receptor subunit that functions as the common beta chain of type I cytokine receptors for granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin-3, and interleukin-5 1. The receptor operates by forming heterodimeric complexes with ligand-specific alpha chains and participates in JAK-STAT signaling pathways, where ligand binding stimulates JAK1 activation 2. CSF2RB is critical for immune cell development and function, controlling hematopoietic progenitor differentiation and leukocyte proliferation 3. Clinically, CSF2RB mutations cause hereditary pulmonary alveolar proteinosis (PAP), characterized by surfactant accumulation and alveolar macrophage dysfunction due to impaired GM-CSF signaling 1. Additionally, CSF2RB overexpression has been identified as a shared diagnostic biomarker in periodontitis and primary Sjögren's syndrome, suggesting a role in inflammatory and autoimmune pathways 4. CSF2RB is markedly overexpressed in regulatory T cells from autoimmune disease patients (multiple sclerosis, systemic lupus erythematosus) compared to healthy controls, potentially serving as a disease biomarker 3. Recent evidence indicates CSF2RB-mediated phagocytosis by myeloid cells contributes to lipid nanoparticle clearance in vivo 5.