Results showed that MSCs, complete MSC supernatant, and MSC-derived exosomes can promote CD19+CD24hiCD38hi CD19+ B cells (0.700 ± 0.101 vs. 8.200 ± 1.135 vs. 6.343 ± 0.722 vs. 4.907 ± 0.645) and IL-10-producing CD19+ B cells (2.403 ± 0.306 vs. 8.320 ± 0.887 vs. 6.520 ± 0.814 vs. 6.297 vs. 0.667) in ITP-derived CD19+ B cells, while the exosome-depleted MSC supernatant did not show similar effects (B10: 2.403 ± 0.306 vs. 3.117 ± 0.400, CD19+CD24hiCD38hi CD19+ B cells: 0.700 ± 0.101 vs. 1.190 ± 0.24). Here, CD19 is linked to autoimmune thrombocytopenic purpura.