This sorting strategy was chosen to capture the majority of described Breg subsets, including IL-10+T2-MZP, IL-10+MZ, and IL-10+CD1dhiCD5+, which have been shown to exert suppressive capacity via IL-10 in this model of arthritis and in other models of autoimmunity (Brummel and Lenert, 2005, Evans et al., 2007, Tian et al., 2001, Yanaba et al., 2009). Here, IL10 is linked to arthritic joint disease.