NK-cell reconstitution after haploidentical hematopoietic stem-cell transplantations: immaturity of NK cells and inhibitory effect of NKG2A override GvL effect.
Natural killer (NK) cell alloreactivity is reported to mediate strong GvL (graft versus leukemia) effect in patients after haploidentical stem-cell transplantation (SCT) for acute myeloid leukemia (AML). Because subsequent immune reconstitution remains a major concern, we studied NK-cell recovery in 10 patients with AML who received haplomismatched SC transplants, among whom no GvL effect was observed, despite the mismatched immunoglobulin-like receptor (KIR) ligand in the GvH direction for 8 of 10 patients. NK cells generated after SCT exhibited an immature phenotype: the cytotoxic CD3- CD56(dim) subset was small, expression of KIRs and NKp30 was reduced, while CD94/NKG2A expression was increased. This phenotype was associated to in vitro lower levels of cytotoxicity against a K562 cell line and against primary mismatched AML blasts than donor samples. This impaired lysis was correlated with CD94/NKG2A expression in NK cells. Blockading CD94/NKG2A restored lysis against the AML blasts, which all expressed HLA-E, the ligand for CD94/NKG2A. Our present study allows a better understanding of the NK-cell differentiation after SCT. These results revealed that the NK cells generated after haplomismatched SCT are blocked at an immature state characterized by specific phenotypic features and impaired functioning, having potential impact for immune responsiveness and transplantation outcome.
Nguyen
Stephanie
S
Laboratoire d'Immunologie Cellulaire et Tissulaire INSERM U543, Hôpital Pitié-Salpêtrière, 83 Bvd de l'Hôpital 75013 Paris, France. stephanienguyenquoc@hotmail.com
Dhedin
Nathalie
N
Vernant
Jean-Paul
JP
Kuentz
Mathieu
M
Al Jijakli
Ahmad
A
Rouas-Freiss
Nathalie
N
Carosella
Edgardo D
ED
Boudifa
Ali
A
Debré
Patrice
P
Vieillard
Vincent
V
D000293:Adolescent; D000328:Adult; D019002:CD56 Antigen / Q000276:immunology; D002454:Cell Differentiation; D005260:Female; D020544:Graft vs Leukemia Effect / Q000276:immunology*; D006238:Haploidy; D018380:Hematopoietic Stem Cell Transplantation; D006801:Humans; D007694:Killer Cells, Natural / Q000166:cytology* / Q000502:physiology*; D015470:Leukemia, Myeloid, Acute / Q000276:immunology / Q000378:metabolism / Q000473:pathology / Q000628:therapy; D008297:Male; D055654:NK Cell Lectin-Like Receptor Subfamily C; D010641:Phenotype; D011971:Receptors, Immunologic / Q000276:immunology* / Q000378:metabolism*; D055607:Receptors, Natural Killer Cell; D016896:Treatment Outcome
D019002:CD56 Antigen; C527054:KLRC1 protein, human; D055654:NK Cell Lectin-Like Receptor Subfamily C; D011971:Receptors, Immunologic; D055607:Receptors, Natural Killer Cell