Macrophages expressing the IL-4 polarization gene ALOX15+ increased in proportion in active disease (Fig. 2a) and had a similar profile to PLAC8+ and SEPP1+ macrophages, but also expressed MMP9/12 and TREM2. Accordingly, cell-intrinsic expression of ALOX15 was upregulated in cells from patients with active EoE (Fig. 3c,d). Here, MMP9 is linked to eosinophilic esophagitis.