TGFB1 and rheumatoid arthritis: By contrast, application of IgD CSR non-inducing stimuli (LPS plus TGF-β and RA) to similar naive IgM+IgD+ B cells resulted in increased mIgD, no change in VHDJH−Cδm transcripts, and marginal IgD secretion (Fig. 7a, b, Supplementary Fig. 7b).