ERAP1 and colitis: Similarly, these neutrophil subsets were significantly elevated in sulfasalazine-treated ERAP1+/− colitis mice compared to ERAP1+/− controls (Ly6G+, p < 0.01; CD11b+, p < 0.05; Ly6G+CD11b+, p < 0.01), indicating that sulfasalazine treatment failed to suppress neutrophilic inflammation under ERAP1 haploinsufficient conditions.