Consistent with our previous study in AML/MDS, in the present study, the effect of SIRPα mismatch on both cGVHD and relapse protection was observed only in the patients who achieved full (>95%) donor T cell chimerism after allo- HSCT, indicating that enhanced innate immunity may need to activate adaptive immunity first which then leads to a higher risk of cGVHD and a lower risk of relapse. Here, SIRPA is linked to myelodysplastic syndrome.