[Case of HLA-DR8 positive sarcoidosis following polymyositis and Sjögren's syndrome].

A 69-year-old woman had been found to have idiopathic interstitial pneumonia (fibrotic NSIP) in 1997. Proximal muscle weakness appeared in April 2005. Chest CT revealed hilar and mediastinal lymphadenopathy. Polymyositis and Sjögren's syndrome were subsequently diagnosed. We assumed that the interstitial pneumonia had preceded polymyositis and Sjögren's syndrome. A muscle biopsy and transbronchial needle aspiration biopsy demonstrated noncaseating epithelioid cell granulomas. A diagnosis of sarcoidosis complicated with polymyositis and Sjögren's syndrome was made from these findings. Moreover, her HLA genotype contained DR8. HLA-DR8 is considered to be associated with polymyositis, Sjögren's syndrome, and sarcoidosis in Japanese patients. This case suggests the possibility that there are common immunological and genetical pathogenetic mechanisms in autoimmune diseases and sarcoidosis.