We showed that the expression of Il22ra2 was drastically upregulated in polyps of AOM-3DSS-treated GF Clec7a−/− mice (Fig. 3a; Supplementary Fig. 3a, 5a), and IL-22BP levels were also increased in AOM-3DSS-treated SPF Clec7a−/− mice (Supplementary Fig. 5b, c). Here, IL22RA2 is linked to infectious otitis media.