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The HLA class II (DRB1 and DQB1) associations with sarcoidosis have been studied by several groups but often without consistent results. In this paper, we consider the hypothesis that observed inconsistencies relate to distinct, genetically encoded disease phenotypes which differ in prevalence between centres. We therefore typed HLA-DRB1 and DQB1 in 340 UK, 139 Dutch and 163 Japanese sarcoidosis patients and, respectively, 354, 218 and 168 healthy controls from these populations. We applied consistent phenotyping and genotyping and investigated associations between HLA class II alleles and distinct disease phenotypes within and between ethnic groups. DRB1*01 and DQB1*0501 are protective against all manifestations of sarcoidosis. Lung-predominant sarcoidosis is associated with DRB1*12 and *14. Löfgren's syndrome is a common sarcoidosis phenotype in the Dutch and is strongly associated with the DRB1*0301 allele. This phenotype is not seen among the Japanese in whom DRB1*0301 is absent. The same allele is protective for UK uveitis. Sarcoid uveitis is common in Japan. The DRB1*04-DQB1*0301 haplotype is a risk factor for this disease manifestation in Japanese and UK subjects but protective for sarcoidosis overall. We show that distinct sarcoidosis phenotypes have similar genetic associations across ethnic groups. The disease case mix differs between centres and may be explained by different ethnic allelic frequencies.

Background: Chymase is released from mast cells following activation. Evidence suggests that chymase plays an important role in tissue injury and remodeling of the lungs, heart and skin., Objective: We postulated that chymase gene (CMA1) polymorphisms are associated with pulmonary fibrosis in Dutch and with cardiac and skin involvement in Japanese sarcoidosis patients., Patients and Methods: Dutch (n = 153) and Japanese (n = 122) sarcoidosis patients with controls (Dutch, n = 309; Japanese, n = 111) were studied. Pulmonary involvement in Dutch patients as well as clinical manifestations in Japanese patients was evaluated for association with five CMA1 polymorphisms., Results: The CMA1 polymorphisms were not associated with disease susceptibility in either population, or with radiographic evolution in the Dutch or with cardiac or skin involvement in the Japanese patients. The -526 T allele was associated with a lower iVC in Dutch patients., Conclusions: The CMA1 polymorphisms studied do not contribute to disease susceptibility in Japanese or Dutch sarcoidosis patients. CMA1 polymorphisms do not influence radiographic evolution in Dutch sarcoidosis patients, nor do they predispose to cardiac or skin involvement in Japanese patients. However, the association between CMA1 -526 C/T and iVC in the Dutch patients suggests that chymase may modify the functional outcome of pulmonary sarcoidosis.