High expression of interleukin-17A in cutaneous sarcoidosis

Increasing evidence of Th17 pathways is implicated in sarcoidosis granulomatous inflammation and maintenance. Our study evaluated the presence of IL-17A, a downstream proinflammatory cytokine, in cutaneous sarcoidosis biopsies. We found that all 26 biopsy samples had increased expression of IL-17A, predominantly located in macrophages within granulomas, in the cytoplasm of multinucleated histiocytes surrounding the granulomas and within lymphocytic infiltrates surrounding the inflammation.