At d5, 〜30% donor-derived lung monocytes expressed YFP, and a comparable YFP expression was found on donor-derived moCs (Figure 4D), whereas at d33 up to 80% donor-derived moCs expressed YFP (Figure 4E), reflecting that moCs generated during the resolution of allergy had a longer life span and maintained the activity of the CX3CR1 promoter, leading to an efficient YFP locus rearrangement. The gene discussed is CX3CR1; the disease is allergic disease.