Sarcoidosis

Sarcoidosis is a multisystem granulomatous disease of unknown etiology. Clinically, it is mainly characterized by bilateral hilar lymph node enlargement, pulmonary infiltration, and skin and eye lesions, with granulomatous nodules capable of involving all organs throughout the body. It commonly affects young adults, and over 90% of clinical cases show pulmonary changes, characterized by bilateral hilar lymph node enlargement, pulmonary infiltration, and ocular and cutaneous involvement. The liver, spleen, lymph nodes, salivary glands, heart, nervous system, muscles, bones, and other organs may also be affected. A diagnosis can be made when typical clinical and radiographic manifestations are present, along with histologically confirmed non-caseating epithelioid cell granulomas, provided that other granulomatous diseases are excluded. The immunological features of this disease include suppressed delayed-type hypersensitivity skin responses and enhanced type 1 helper T cell (Th1) immune responses, accompanied by increased circulating immune complexes and B cell responses.