In spite of the limitations imposed by sample size, this and other studies suggest that the association of both ERAP1 and ERAP2 with psoriasis is probably variable in this heterogeneous pathology, and a precise definition of the role of these enzymes, and their functional interaction with C*06:02, should benefit from large scale studies allowing robust statistical assessments within disease subsets. This evidence concerns the gene ERAP2 and psoriasis.