Monitoring of Measles-specific Immune Status in Adult Allogeneic Hematopoietic Stem Cell Transplant Recipients (MaRROwVacc)

Inclusion Criteria: Study population: Aged ≥ 18 years and ≤ 75 years, Have received an allo-HSCT ≥ 24 months ago, In complete remission of initial hematologic disease and with successful engraftment (recipient chimerism <0.3% on whole blood), Without extensive chronic GVHD, Having given their written consent, Affiliated to a social security plan, Able to attend all scheduled visits and to comply with all study procedures. Healthy volunteers: Aged ≥ 18 years and ≤ 75 years, Having a history of measles (=convalescent) or have been vaccinated in the past with two doses of MMR (=vaccinated), Having given their written consent, Affiliated to a social security plan. Exclusion Criteria: Study population: History of autoimmune disease or acquired immunodeficiency (other than the hematological disease), Patients undergoing pharmacological immunosuppression or biotherapy or extracorporeal photopheresis at the time of inclusion, or whose immunosuppressive treatment (corticosteroids and anti-rejection agents) has been stopped less than 3 months ago, or whose biotherapy (anti-cytokines, anti-JAK, anti-CD20 etc.) has been stopped less than 3 months ago (12 months for anti-CD20 including rituximab), or whose extracorporeal photopheresis has been stopped less than 3 months ago, Patients having received ≥ 1 infusion of IVIG in the 8 months prior to inclusion, Patients whose last HSCT was an autograft, Patients with known chronic active infection with human immunodeficiency virus (HIV) and/or hepatitis B or C virus(es), Patients deprived of liberty by judicial or administrative decision, Patients under legal protection or unable to consent to the study, Patients participating in another interventional research study with an exclusion period still in progress at pre-inclusion, Pregnant, parturient or breast-feeding women. Healthy volunteers: History of autoimmune disease or acquired immunodeficiency, History of pharmacological immunosuppression or biotherapy discontinued less than 3 months ago (12 months for anti-CD20 including rituximab), History of IVIG infusion in the 8 months prior to inclusion, Persons deprived of liberty by judicial or administrative decision.