Hematopoietic cell transplantation (HCT) represents a cardinal therapy for hematological malignancy otherwise incurable. However, HCT can be complicated by disease recurrence, graft versus host disease (GVHD) and infections. After HCT, reconstituting T and NK cells protect against infection and relapse, but they are also involved in the pathogenesis of GVHD. The aims of my PhD project were to improve the understanding of T and NK-cell reconstitution, using samples from both healthy donor and patients after transplant and different technical approaches (flow cytometry, mass cytometry, RNA sequencing, and ex vivo functional assay) and to develop post-transplant T and NK cell-based immunotherapeutic strategies. First, we showed that delayed early T-cell recovery, a higher Treg/ Tcon ratio, an increased PD-1 expression on memory T cells, and an enriched immature NK phenotype were observed after haploidentical HCT (haplo-HCT) with post-transplant cyclophosphamide. In addition, the expansion of functionally impaired immature CD56brightCD16+ NK cells after haplo-HCT can be enhanced with in vitro interleukin-15 priming. Second, we initiated a phase I trial of adoptively transferred cytokine-induced memory-like (CIML) NK cells in patients with myeloid malignancies who relapsed after haplo-HCT. In the first 6 enrolled patients, infusion of CIML NK cells led to a rapid 10- to 50-fold in vivo expansion that was sustained over months. The infusion was well tolerated, with fever and pancytopenia as the most common adverse events. Based on these preliminary data, CIML NK cells may serve as a promising platform for the treatment of posttransplant relapse of myeloid disease. Finally, we focused on the balancing of T cell response to control GVHD occurrence. CD6, a pan-T cell co-stimulatory receptor, helps to stabilize the immunological synapse between the T cell and the APC, upon ligation, with its ligand, activated leukocyte cell adhesion molecule (ALCAM). In this context, CD6-ALCAM binding promotes T cell activation, proliferation, maturation. We showed that CD6 T cells reconstituted early after transplant with Treg expressing lower levels of CD6 compared to Tcon and CD8+ T cells. After onset of aGVHD, both CD6 and ALCAM expression was maintained. Itolizumab inhibited CD4+ and CD8+ T cell activation and proliferation in the setting of aGVHD in ex vivo experiments, without mediate direct cytolytic activity or antibody-dependent cytotoxicity. Our results identify the CD6-ALCAM pathway as a potential target for aGVHD control. A phase I/II study using itolizumab as first line treatment in combination with steroids for patients with aGVHD is currently ongoing. In conclusion, these results highlight the need of balancing the effector and tolerogenic properties of the immune system reconstituting after HCT and suggest different strategies to enhance or moderate the T and NK cells functions.

Il trapianto di cellule ematopoietiche (HCT) rappresenta una terapia cardine per il trattamento delle neoplasie ematologiche altrimenti incurabili. Tuttavia, la procedura di trapianto può essere gravata dalla recidiva della malattia, dalla malattia del trapianto contro l'ospite (GVHD) e dalle infezioni. Le cellule T e NK che ricostituiscono dopo l'HCT proteggono da infezioni e recidive, ma sono anche coinvolte nella patogenesi della GVHD. Gli obiettivi del mio progetto di dottorato erano di migliorare la comprensione della ricostituzione delle cellule T e NK, utilizzando campioni di donatori sani e pazienti dopo il trapianto e diversi approcci tecnici (citometria a flusso, citometria di massa, sequenziamento dell'RNA e test funzionale ex vivo) e sviluppare nuove strategie immunoterapiche basate sui linfociti T e NK dopo HCT. In primo luogo, abbiamo dimostrato che un ritardo nel recupero dei linfociti T, un rapporto Treg/Tcon più elevato, un'aumentata espressione di PD-1 sui linfociti T di memoria e un arricchimento di cellule NK a fenotipo immaturo sono stati osservati dopo HCT aploidentico (aplo-HCT) con l’utilizzo di ciclofosfamide post-trapianto. Inoltre, la funzione delle cellule NK CD56brightCD16+ immature funzionalmente alterate dopo aplo-HCT può essere migliorata con l’utilizzo dell'interleuchina-15 in vitro. In secondo luogo, abbiamo avviato uno studio di fase I sulle cellule cytokine-induced memory-like (CIML) NK infuse da donatore haploidentico in pazienti con neoplasie mieloidi che hanno avuto una recidiva dopo aplo-HCT. Nei primi 6 pazienti arruolati, l'infusione di cellule CIML-NK ha portato a una rapida espansione in vivo da 10 a 50 volte, che è stata mantenuta per mesi. L'infusione è stata ben tollerata, con febbre e pancitopenia come eventi avversi più comuni. Sulla base di questi dati preliminari, le cellule CIML-NK possono fungere da piattaforma per il trattamento della recidiva post-trapianto delle patologie mieloidi. Infine, ci siamo concentrati sul bilanciamento della risposta dei linfociti T per controllare l’incidenza di GVHD. CD6, un recettore co-stimolatorio dei linfociti T, che aiuta a stabilizzare la sinapsi immunologica tra la cellula T e l'APC, dopo legame con il suo ligando, la molecola di adesione delle cellule leucocitarie attivate (ALCAM). In questo contesto, il legame CD6-ALCAM promuove l'attivazione, la proliferazione e la maturazione delle cellule T. Abbiamo dimostrato che le cellule T CD6 ricostituivano subito dopo il trapianto, con le cellule Treg che esprimono livelli inferiori di CD6 rispetto alle cellule Tcon e cellule T CD8+. Dopo l'insorgenza della aGVHD, l'espressione sia di CD6 che di ALCAM è stata mantenuta. Itolizumab ha inibito l'attivazione e la proliferazione delle cellule T CD4+ e CD8+ nell'ambito di aGVHD in esperimenti ex vivo, senza mediare l'attività citolitica diretta o la citotossicità anticorpo-dipendente. I nostri risultati identificano la via di CD6-ALCAM come potenziale bersaglio per il controllo dell'aGVHD. Uno studio di fase I/II che utilizza itolizumab come trattamento di prima linea in combinazione con steroidi per i pazienti con aGVHD è attualmente in corso. In conclusione, questi risultati evidenziano la necessità di bilanciare le proprietà effettrici e tolerogeniche del sistema immunitario che si ricostituisce dopo HCT e suggeriscono differenti strategie per promuovere o moderare le funzioni delle cellule T e NK.

(2023). Understanding T and NK cell reconstitution after allogeneic hematopoietic cell transplantation: a path to improve graft versus leukemia and minimize graft versus host disease. (Tesi di dottorato, Università degli Studi di Milano-Bicocca, 2023).

Understanding T and NK cell reconstitution after allogeneic hematopoietic cell transplantation: a path to improve graft versus leukemia and minimize graft versus host disease

RAMBALDI, BENEDETTA
2023

Abstract

Hematopoietic cell transplantation (HCT) represents a cardinal therapy for hematological malignancy otherwise incurable. However, HCT can be complicated by disease recurrence, graft versus host disease (GVHD) and infections. After HCT, reconstituting T and NK cells protect against infection and relapse, but they are also involved in the pathogenesis of GVHD. The aims of my PhD project were to improve the understanding of T and NK-cell reconstitution, using samples from both healthy donor and patients after transplant and different technical approaches (flow cytometry, mass cytometry, RNA sequencing, and ex vivo functional assay) and to develop post-transplant T and NK cell-based immunotherapeutic strategies. First, we showed that delayed early T-cell recovery, a higher Treg/ Tcon ratio, an increased PD-1 expression on memory T cells, and an enriched immature NK phenotype were observed after haploidentical HCT (haplo-HCT) with post-transplant cyclophosphamide. In addition, the expansion of functionally impaired immature CD56brightCD16+ NK cells after haplo-HCT can be enhanced with in vitro interleukin-15 priming. Second, we initiated a phase I trial of adoptively transferred cytokine-induced memory-like (CIML) NK cells in patients with myeloid malignancies who relapsed after haplo-HCT. In the first 6 enrolled patients, infusion of CIML NK cells led to a rapid 10- to 50-fold in vivo expansion that was sustained over months. The infusion was well tolerated, with fever and pancytopenia as the most common adverse events. Based on these preliminary data, CIML NK cells may serve as a promising platform for the treatment of posttransplant relapse of myeloid disease. Finally, we focused on the balancing of T cell response to control GVHD occurrence. CD6, a pan-T cell co-stimulatory receptor, helps to stabilize the immunological synapse between the T cell and the APC, upon ligation, with its ligand, activated leukocyte cell adhesion molecule (ALCAM). In this context, CD6-ALCAM binding promotes T cell activation, proliferation, maturation. We showed that CD6 T cells reconstituted early after transplant with Treg expressing lower levels of CD6 compared to Tcon and CD8+ T cells. After onset of aGVHD, both CD6 and ALCAM expression was maintained. Itolizumab inhibited CD4+ and CD8+ T cell activation and proliferation in the setting of aGVHD in ex vivo experiments, without mediate direct cytolytic activity or antibody-dependent cytotoxicity. Our results identify the CD6-ALCAM pathway as a potential target for aGVHD control. A phase I/II study using itolizumab as first line treatment in combination with steroids for patients with aGVHD is currently ongoing. In conclusion, these results highlight the need of balancing the effector and tolerogenic properties of the immune system reconstituting after HCT and suggest different strategies to enhance or moderate the T and NK cells functions.
BECCHETTI, ANDREA
BIONDI, ANDREA
RITZ, JEROME
immunoricostituzione; HCT; GVHD; checkpoint inibitore; terapia cellulare NK
immunereconstitution; HCT; GVHD; checkpoint inhibitor; NK cell therapy
MED/38 - PEDIATRIA GENERALE E SPECIALISTICA
English
23-gen-2023
MEDICINA TRASLAZIONALE E MOLECOLARE - DIMET
35
2021/2022
open
(2023). Understanding T and NK cell reconstitution after allogeneic hematopoietic cell transplantation: a path to improve graft versus leukemia and minimize graft versus host disease. (Tesi di dottorato, Università degli Studi di Milano-Bicocca, 2023).
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Descrizione: Understanding T and NK cell reconstitution after allogeneic hematopoietic cell transplantation: a path to improve graft versus leukemia and minimize graft versus host disease
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/402375
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