Diagnosis and treatment of sarcoidosis based on immunological etiology and mechanisms.

Pulmonary sarcoidosis is a multisystem disease characterized by non-caseating granulomas, and its pathogenesis involves genetic susceptibility and abnormal immune responses triggered by environmental antigens. This article reviews the immunological etiology and mechanisms of pulmonary sarcoidosis, systematically discussing its pathogenetic basis, core immune mechanisms, and the role of key immunological biomarkers (such as sIL-2R, CD4+/CD8+ ratio in BALF, and HRCT) in diagnosis and assessment. It also outlines the step-up therapy, ranging from glucocorticoids to immunomodulators, biologic agents, and emerging anti-fibrotic therapies, aiming to provide an immunological basis for the precise diagnosis and treatment of pulmonary sarcoidosis.