BTK and idiopathic aplastic anemia: To this end, we transferred donor pan T cells derived from WT mice and Btk−/− mice into sublethally irradiated BDF1 recipients to establish an immune-mediated aplastic anemia (AA) model.18,19 Graft-vs-host responses cause severe BM destruction and blood pancytopenia in the host, which is mainly attributed to T-cell responses.20,21 T-cell development was normal in Btk−/− mice3 (Supplementary Fig. 2).