IL10 and infection: Although lymphocytes, mast cells, bronchial epithelial cells (Bonfield et al, 1995) and type I pneumocytes (Haase et al, 2007) produce IL-10, monocytes and macrophages, and polymorphonuclear cells have been identified as its major source during a variety of infections (Couper et al, 2008a; Cyktor & Turner, 2011), and microbes have evolved mechanisms by which they subvert production of IL-10.