M2 macrophages express high levels of arginase (Arg) 1, chitinase 3‐like protein 3 (Chi3l3, Ym1) and resistin‐like α (Retnla, Fizz1), which suppress inflammation and facilitate tissue repair.20 Thus, upon bacterial invasion, the different phenotypes of macrophage activation determine the outcome of infection to some extent. The gene discussed is RETNLB; the disease is infection.