title: Clinical factors influencing T-cell receptor excision circle (TRECs) counts following allogeneic stem cell transplantation in adults.
abstract: To ascertain the clinical factors involved in T-cell reconstitution after allogeneic stem cell transplantation (SCT), we evaluated serial assessments of lymphocyte subsets by flow cytometry and TRECs levels by quantitative PCR in 83 adult patients. Patient age >25 years, unrelated donor, CMV infection and acute graft-versus-host disease (GVHD) adversely affected CD3(+) and CD8(+) T-cell recovery after SCT (p < 0.05). TRECs were low or undetectable during the first months after transplant and progressively increased thereafter. However, median TRECs of patients did never achieve normal values compared to healthy donors (median follow-up 9 months, range 2-42). Presence and severity of chronic GVHD significantly affected TRECs counts: patients with chronic GVHD had lower TRECs than patients without GVHD at 9, 12 and 24 months after SCT (p = 0.002, p = 0.022, p = 0.015). Patients with limited chronic GVHD had higher TRECs compared to patients with extensive GVHD (p = 0.018). No relationship was observed between fungal or bacterial infections and TRECs. Nonetheless, CMV infection was associated with lower TRECs (p = 0.032). Our data support the concept that adult thymus contributes with a slow but continuous production of thymic T cells to immune reconstitution after SCT. Chronic GVHD is the main factor associated to a delay in TRECs counts recovery.
authors.affiliation: Department of Hematology, Institute of Hematology and Oncology, Institut d'Investigacions Biomèdiques August Pi I Sunyer, IDIBAPS, Hospital Clínic, University of Barcelona, Spain.
authors.forename: Mónica
authors.initials: M
authors.lastname: Jiménez
authors.forename: Carmen
authors.initials: C
authors.lastname: Martínez
authors.forename: Guadalupe
authors.initials: G
authors.lastname: Ercilla
authors.forename: Enric
authors.initials: E
authors.lastname: Carreras
authors.forename: Alvaro
authors.initials: A
authors.lastname: Urbano-Ispízua
authors.forename: Marta
authors.initials: M
authors.lastname: Aymerich
authors.forename: Neus
authors.initials: N
authors.lastname: Villamor
authors.forename: Nuria
authors.initials: N
authors.lastname: Amézaga
authors.forename: Montserrat
authors.initials: M
authors.lastname: Rovira
authors.forename: Francesc
authors.initials: F
authors.lastname: Fernández-Avilés
authors.forename: Emili
authors.initials: E
authors.lastname: Montserrat
mesh_terms: D000328:Adult; D002478:Cells, Cultured; D005260:Female; D015332:Gene Rearrangement, alpha-Chain T-Cell Antigen Receptor; D016694:Gene Rearrangement, delta-Chain T-Cell Antigen Receptor; D006086:Graft vs Host Disease / Q000276:immunology; D006801:Humans; D016130:Immunophenotyping; D018655:Lymphocyte Count; D008297:Male; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000096:biosynthesis / Q000235:genetics*; D016692:Receptors, Antigen, T-Cell, gamma-delta / Q000096:biosynthesis / Q000235:genetics*; D033581:Stem Cell Transplantation / Q000009:adverse effects; D016176:T-Lymphocyte Subsets / Q000276:immunology* / Q000378:metabolism*; D013950:Thymus Gland / Q000166:cytology / Q000276:immunology / Q000378:metabolism; D014184:Transplantation, Homologous
chemical_list: D016693:Receptors, Antigen, T-Cell, alpha-beta; D016692:Receptors, Antigen, T-Cell, gamma-delta