IL10 and graft versus host disease: Our findings clearly demonstrate that protection against aGVHD is attributed to the donor’s IL10 genotype, as evidenced by three main factors: (i) all patients in this study received myeloablative conditioning, (ii) recipient IL-10 SNPs were not found to be associated with differences in GVHD outcomes, and (iii) chimerism studies demonstrated high donor chimerism in the T- and myeloid cells at 1 month post-transplant.