FIGURE 7.

B lymphocyte interactions with resident bone marrow (BM) mesenchymal stromal cells (MSCs) vs nonresident placental MSCs (P‐MSCs) result in disparate outcomes. BM‐MSCs supported but P‐MSCs suppressed stimulated peripheral B‐cell proliferation and further differentiation, whereas P‐MSCs more significantly increased multiple populations of IL‐10‐expressing regulatory B cells (Bregs). Multifactorial differences in expression of relevant factors by the two sources of MSCs are likely involved in these divergent outcomes