WHAT ARE GRANULOMAS CAUSED BY SARCOIDOSIS?
Mechanism of granuloma formation
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Description of granulomas
Granulomas are characteristic signs of symptomatic sarcoidosis. They are relatively small groups of inflamed cells with intense proliferative activity.
Central zone → rich in macrophages (at different stages of activation and differentiation) and Langerhans cells surrounded by CD4 lymphocytes (or T-helper cells).
Peripheral zone → rich in CD8 (suppressor) lymphocytes. These cells present antigens (macrophages) and plasma cells. The antigen binds as a key to the appropriate receptor.
Although granulomas can occur in any anatomical location, they tend to originate in the lungs and then spread to areas such as the skin, central nervous system, eyes, heart, lymph nodes and other organs.
The image shows granulomas and lesions in the lungs
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