We identified two populations of interstitial macrophages (HLA-DR+CD206−) in BAL; (1) CD11c+CD16hi population increasing during the acute phase of infection that was associated with IL-6 levels in the plasma, and (2) a long-lasting CD11b+ and CD16hi population accumulating in lungs of both AGM and RM, particularly in those with increased disease severity. This evidence concerns the gene ITGAX and infection.