Our data show that, although the CCR2 KO has no effect on the development nor the resolution of MA-ARDS, CCR2 is crucial to re-establish the homeostasis of pulmonary leukocytes, since the reappearance of eosinophils and interstitial macrophages was mitigated in the lungs of PbNK65-infected CCR2 KO mice. This evidence concerns the gene CCR2 and microtia.