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Letters to the Editor
Figure 2. T-cell expansion, control reactivity and alloreactivity response. Eleven samples of peripheral blood mononuclear cells obtained from 22 patients 1 month after haploidentical hematopoietic stem cell transplantation were propagated towards mismatched HLA-class II alleles of the recipient in a T-cell and Hela-cell co-culture, using a panel of Hela cell lines, each transduced with a single HLA-class II allele. T-cell expansion of individual cultures at day 21 is pre- sented as fold increase in cell number. Propagated T cells were subsequently tested for (allo)reactivity towards that same mismatched, and matched HLA-class II alleles. The response was quantified by CD137 upregulation on CD4+ T cells (%CD137+/CD4+) and presented for the alloreactivity as ‘fold increase (%CD137+/CD4+)’ of reactivity towards HeLa cells transduced with mismatched HLA-class II alleles relative to reactivity towards the not-transduced ‘empty’ HeLa cells. The level of T-cell expansion, control reactivity (towards matched alleles) and alloreactivity response are presented in a four-color grading scale. PBMC: peripheral blood mononuclear cells; HAPLO: haploidentical stem cell transplantation; HLA: human leukocyte antigen; FI: fold increase.
of antigen-presenting cells might evoke a stronger CD4+ T-cell response.
In conclusion, this study showed the presence of
alloreactive CD4+ T cells early after haploidentical HSCT,
although less frequently than previously observed in the
dUCBT-setting.3 Intensified immunosuppression, espe-
cially PT-Cy, to prevent GvHD might blunt the CD4+
T-cell response, with possible loss of part of the
graft-versus-leukemia activity. Our observations might
help the understanding of the kinetics of immune
responses in both haploidentical and cord blood trans-
plantation. However, a prospective comparison would be
needed to quantify the different immune responses in
more detail. Moreover bone marrow was the sole source
of the grafts in our study, whereas the use of PBSC as a
transplant source might be associated with increased
14
Burak Kalin,1 Elisabetta Metafuni,2 Mariëtte ter Borg,1 Rebecca Wijers,3 Eric Braakman,1 Cor H. J. Lamers,3 Andrea Bacigalupo2 and Jan J. Cornelissen1
1Erasmus University Medical Center, Department of Hematology, Rotterdam, the Netherlands; 2Istituto di Ematologia, Fondazione Policlinico Universitario A Gemelli IRCCS, Roma, Italy and 3Erasmus MC Cancer Institute, Department of Medical Oncology, Laboratory of Tumor Immunology, Rotterdam, the Netherlands
Correspondence:
JAN J. CORNELISSEN - j.cornelissen@erasmusmc.nl.
doi:10.3324/haematol.2019.244152
Disclosures: no conflicts of interests to disclose.
Contributions: BK, AB, CHJL and JJC contributed to the study design; all authors provided study materials or patients; all authors were involved in collection and assembly of clinical data; BK, AB and JJC were involved in analyzing and interpreting the data and writing this report; and all authors reviewed and approved the final version of the manuscript.
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