Nature Reviews Immunology8, 958–969 (2008)

The authors would like to include as an addendum the contribution of R. Stout and J. Suttles to the conceptual framework of macrophage plasticity that was mentioned in our Review. Their ideas on the ability of macrophages to change their functional phenotype in response to their tissue environment were previously published in two review articles (J. Leuk. Biol.76, 509–513 (2004) andImmunol. Rev.206, 60–71 (2005)).