S100A8 and rheumatoid arthritis: The observation that alleviation of disease with anti-TNF therapy leads to a decrease of joint-infiltrating S100A8/9+ macrophages,26 presumably by enhanced efflux of these cells from the synovium,26 while the number of potential resident-tissue (CD163+) macrophages remained unchanged54 would argue against an active role of monocyte-derived macrophages in the resolution of RA.