COL17A1 and pemphigus: Overall, 0.31 % (CI: 0.18–0.44 %) of healthy blood donors had autoantibodies against pemphigus antigens, and 0.52 % (95 % CI: 0.36–0.69 %) showed reactivity with BP180-NC16A, the relevant pathogenic epitope of BP [23–25].