0000000000082191
AUTHOR
Chrysanthi Tsamadou
showing 9 related works from this author
P046 Deconstructing HLA-C mismatch in hematopoietic stem cell transplantation
2016
Contrary to other HLA loci, allele vs antigen mismatches in HLA-C appear to differentially impact HSCT outcome. Aim of this study was to investigate the independent role of other factors characterizing a patient’s HLA-C non-shared allele, in HSCT outcome as well as their distribution in allele vs antigen mismatched cases. 288 9/10 HLA-C mismatched unrelated transplant pairs, were additionally genotyped by sequence based typing for rs9264942(C/T) and rs67384697(ins/del), which are considered surrogate markers of HLA-C expression levels. A proxy MFI model as previously described (Petersdorf et al., Blood 2014), was also implemented in the analysis. All patient non-shared alleles were characte…
P043 HLA-DPB matching and donor cytomegalovirus positive (CMV+) status: An “unconventional alliance” associated with a decreased relapse incidence in…
2017
Aim While the role of HLA-DPB1 (DP) compatibility in uHSCT regarding graft versus host disease (GVHD)- and graft versus leukaemia (GVL)-effects has been extensively discussed, its interaction with donor CMV status (dCMV), remains elusive. The aim of this study was, to investigate the impact of dCMV status in DP matched (DPM) and mismatched (DPMM) uHSCT. Methods 1749 HSCT transplant (Tx) pairs were DP genotyped with an exon 2 amplicon based NGS approach in order to assess their DP matching status. CMV sero-status as well as clinical data were retrieved from the German Stem Cell Registry. Overall survival (OS), relapse incidence (RI) and chronic GvHD (cGvHD) were defined as endpoints, while s…
The Human Leukocyte Antigen-DPB1 Degree of Compatibility Is Determined by Its Expression Level and Mismatch Permissiveness: A German Multicenter Anal…
2021
T-cell epitope matching according to the TCE3 algorithm classifies HLA-DPB1 mismatches in permissive and non-permissive. This classification has been shown to be predictive for mortality and acute GvHD (aGvHD) events in large international cohorts. We retrospectively genotyped HLA-DPB1 in 3523 patients transplanted in Germany between 2000 and 2014 and in their unrelated donors using an Illumina amplicon-NGS based assay. Aim of the study was to evaluate DP-compatibility beyond the established TCE3 algorithm by assessing the combined effect of several DP-mismatch parameters on post-transplant outcome. We implemented an extended DP-mismatch assessment model where TCE3, DP allotype expression w…
OR26. Investigating the impact of patient’s non-shared HLA-C Allotype expression levels in A 9/10 Single HLA-C mismatched hematopoieticstem cell tran…
2018
Aim Petersdorf et al. reported in 2014 an association between patient high expressed HLA-C (C) allotypes and inferior HSCT outcome using an imputed C-expression model (Apps et al., 2013). This study aims at: a) examining the validity of Apps et al. model in Caucasians by using the same methodology in a sample of 400 healthy German blood donors. b) specifically investigating the effect of patient’s non-shared (PNS) C expression levels on outcome by applying C expression imputed data in a 9/10 HLA C-mismatched HSCT setting. Methods Buffy coats from 400 healthy German blood donors were tested by flow cytometry as previously described (Apps et al., 2013) in order to determine C expression on ly…
Impact of Donor Activating KIR Genes on HSCT Outcome in C1-Ligand Negative Myeloid Disease Patients Transplanted with Unrelated Donors-A Retrospectiv…
2017
Natural Killer cells (NK) are lymphocytes with the potential to recognize and lyse cells which escaped T-cell mediated lysis due to their aberrant HLA expression profiles. Killer cell immunoglobulin-like receptors (KIR) influence NK-cell activity by mediation of activating or inhibitory signals upon interaction with HLA-C (C1, C2) ligands. Therefore, absence of ligands for donor inhibitory KIRs following hematopoietic stem cell transplantation (HSCT) may have an influence on its outcome. Previous studies showed that C1 negative patients have a decreased HSCT outcome. Our study, based on a cohort of 200 C1-negative patients, confirmed these findings for the endpoints: overall survival (OS: H…
Increased age-associated mortality risk in HLA-mismatched hematopoietic stem cell transplantation.
2016
We investigated a possible interaction between age-associated risk and HLA-mismatch associated risk on prognosis in different age categories of recipients of unrelated hematopoietic stem cell transplants (HSCT) (n=3019). Patients over 55 years of age transplanted with 8/10 donors showed a mortality risk of 2.27 (CI 1.70–3.03, P<0.001) and 3.48 (CI 2.49–4.86, P<0.001) when compared to 10/10 matched patients in the same age group and to 10/10 matched patients aged 18–35 years, respectively. Compared to 10/10 matched transplantations within each age category, the Hazards Ratio for 8/10 matched transplantation was 1.14, 1.40 and 2.27 in patients aged 18–35 years, 36–55 and above 55 years. Model…
Donor Genetic Determinant of Thymopoiesis rs2204985 Impacts Clinical Outcome after Single HLA Mismatched HSCT
2021
Abstract Introduction: A common genetic variant within the TCRA-TCRD locus has been recently identified as a predictive factor of thymic function and T cell repertoire diversity (Clave et al., 2018). Specifically it was shown in a mouse model that transplantation of rs2204985 AA human hematopoietic stem cells (HSC) into immunodeficient mice led to lower thymocyte counts and poorer TCR diversity. T cell mediated pathways are known to play a significant role in immunological processes affecting HSCT outcome like GvL, GvH and infection. Aim of this study was to investigate the potential impact of donor rs2204985 genotype on patient's outcome after unrelated HSCT. Methods: The study included 2,…
Matching for the MICA-129 polymorphism is beneficial in unrelated hematopoietic stem cell transplantation.
2016
Major histocompatibility complex class I polypeptide-related sequence A (MICA) is a highly polymorphic ligand of the activating NKG2D receptor on natural killer (NK) cells, γδ-T cells, and NKT cells. MICA incompatibilities have been associated with an increased graft-versus-host disease (GVHD) incidence, and the MICA-129 (met/val) dimorphism has been shown to influence NKG2D signaling in unrelated hematopoietic stem cell transplantation (uHSCT). We investigated the effect of MICA matching on survival after uHSCT. We sequenced 2172 patients and their respective donors for MICA. All patients and donors were high-resolution HLA-typed and matched for 10/10 (n = 1379), 9/10 (n = 636), or 8/10 (n…
Human leukocyte antigen-E mismatch is associated with better hematopoietic stem cell transplantation outcome in acute leukemia patients
2017
The immunomodulatory role of human leukocyte antigen (HLA)-E in hematopoietic stem cell transplantation (HSCT) has not been extensively investigated. To this end, we genotyped 509 10/10 HLA unrelated transplant pairs for HLA-E, in order to study the effect of HLA-E as a natural killer (NK)-alloreactivity mediator on HSCT outcome in an acute leukemia (AL) setting. Overall survival (OS), disease free survival (DFS), relapse incidence (RI) and non-relapse mortality (NRM) were set as endpoints. Analysis of our data revealed a significant correlation between HLA-E mismatch and improved HSCT outcome, as shown by both univariate (53% vs. 38%, P=0.002, 5-year OS) and multivariate (hazard ratio (HR)…