Relationship between BM and PB TGF-β concentrations. The concentrations of TGF-β1 (both active and latent forms) in BM and PB plasma were measure by ELISA. (•) Normal subject; (□) patient with ITP; (▵) patient with ITP after PSL treatment. A positive correlation was observed in both active and latent TGF-β1 (r= .82 and .85, respectively). In each subject, the TGF-β1 concentrations in BM were consistently higher than those in the PB. (A) Active TGF-β1; (B) latent TGF-β1.