COHORT 1 = Matched Sibling Donors couples (MSD couples) INCLUSION CRITERIA  recipient of HSCT selected from the French national database CRYOSTEM adult patients (18-50 years old) transplanted in first remission receiving myeloablative conditioning without anti-thymoglobulin 16 couples without any sign of GVH (8 males and 8 females) 16 couples with aGVH without cGVH 9 couples with cGVH without aGVH 9 couples with both cGVH and aGVH. EXCLUSION CRITERIA insufficient DNA material after Miltenyi extraction  COHORT 2 = Haploidentical couples INCLUSION CRITERIA  patient undergoing a haploidentical HSCT in the Hematology Department of Nancy's University Hospital, Lorraine, France (French Minister registration number : DC-2020-4068) EXCLUSION CRITERIA insufficient DNA material after Miltenyi extraction (7 MSD couples)