title: Prognostic utility of routine chimerism testing at 2 to 6 months after allogeneic hematopoietic cell transplantation.
abstract: The utility of routine chimerism analysis as a prognostic indicator of subsequent outcomes after allogeneic hematopoietic cell transplantation (HCT) with myeloablative conditioning regimens remains controversial. To address this controversy, routine chimerism test results at 2 to 6 months after HCT with myeloablative conditioning regimens were evaluated for association with subsequent risk of chronic graft-versus-host disease (GVHD), nonrelapse mortality (NRM), relapse, and overall mortality. Only 70 of 1304 patients (5%) had < 95% donor-derived cells in the marrow. Low donor chimerism in the marrow occurred more often in patients with low-risk diseases compared with those with higher-risk diseases and was significantly associated with a reduced risk of chronic GVHD. Among 673 patients evaluated, 164 (24%) had < 85% donor-derived T cells in the blood. Low donor T cell chimerism was more frequent in patients with low-risk diseases compared with those with higher-risk diseases, in those who received conditioning with busulfan compared with those who received conditioning with total body irradiation, and in those with lower-grade acute GVHD. Low donor T cell chimerism in the blood was significantly associated with a reduced risk of chronic GVHD but not with a reduced risk of relapse, NRM, or overall mortality. Routine testing of chimerism in the marrow and blood at 2 to 6 months after HCT with myeloablative conditioning regimens may be helpful in documenting engraftment in clinical trials, but provides only limited prognostic information in clinical practice.
authors.affiliation: Bone Marrow Transplantation Laboratory Unit, National Cancer Institute, Cairo University, Cairo, Egypt.
authors.forename: Ghada I
authors.initials: GI
authors.lastname: Mossallam
authors.forename: Azza M
authors.initials: AM
authors.lastname: Kamel
authors.forename: Barry
authors.initials: B
authors.lastname: Storer
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Martin
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001854:Bone Marrow Cells / Q000276:immunology*; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D006086:Graft vs Host Disease / Q000276:immunology; D018380:Hematopoietic Stem Cell Transplantation / Q000379:methods*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008875:Middle Aged; D016019:Survival Analysis; D013601:T-Lymphocytes / Q000276:immunology; D018183:Transplantation Chimera / Q000276:immunology*; D019172:Transplantation Conditioning / Q000379:methods; D016896:Treatment Outcome; D055815:Young Adult