To our surprise, using a combination of in vivo approaches, including transgenic mice (IL4Rαfl/fl.CX3CR1Cre) and mixed bone marrow chimaeras, we found that during infection driven inflammation, IL4Rα on colonic macrophages was completely dispensable for the emergence of RELMα+Ym1+ macrophages. The gene discussed is IL4R; the disease is infection.