FCGR2A and sarcoidosis: In addition, the differences found in the percentage of individual alleles and genotypes of the FCGR2A and FCGR2C genes may suggest the presence of a different pathomechanism of the development of Stages I/II and III/IV SA, and explain the previously demonstrated greater immunocomplexemia in Stage I/II than in sarcoidosis in Stage III/IV [16,113].