Ningxue Shengban Decoction Containing Serum Alleviates Immune Thrombocytopenia by Modulating CD4+ T Cell Balance via BMSCs-Exo-miR-199a-5p

• BMSCs-Exo derived miR-199a-5p modulates CD4+ T cell immune balance by promoting Treg/Th2 and suppressing Th1/Th17 responses. • NXSBD containing serum enhances the therapeutic efficacy of BMSCs-Exo by upregulating miR-199a-5p levels. • BMSCs-Exo treatment ameliorates ITP in mice by increasing platelet counts, reducing autoantibodies, and improving megakaryocyte maturation. • The study identifies miR-199a-5p as a novel therapeutic target for ITP and highlights the potential of NXSBD-primed BMSCs-Exo as a cell-free therapy.