Validation of the disease risk index for outcome of patients undergoing allogeneic hematopoietic stem cell transplantation after T cell depletion.

Identification of pretransplantation risk factors is important in evaluating patient outcomes after hematopoietic stem cell transplantation. Current scoring schemes, such as the European Group for Blood and Marrow Transplantation risk score or the Hematopoietic Cell Transplantation-Specific Comorbidity Index, may under-rate disease and disease status at the time of transplantation. The recently published Disease Risk Index (DRI) specifically investigates these aspects by defining 4 risk groups (low, intermediate, high, very high) with significant differences in overall survival (OS). We retrospectively investigated whether the DRI could be applied at the transplantation center of Geneva's University Hospitals (Geneva, Switzerland), where 64% of patients are underwent transplantation with T cell-depleted grafts (TDEP). We analyzed 409 patients with various hematological malignancies who underwent transplantation between January 1998 and October 2012. Using the DRI, the 4-year OS for the low, intermediate, high, and very high groups was 82%, 53%, 27%, and 31%, respectively (P < .0001). For TDEP patients, the 4-year OS for low, intermediate, and high overall risk groups was 86%, 53%, and 33%, respectively (P < .0001). As patients in the very high overall risk group are usually not eligible for TDEP, our group comprised too few patients (n = 3) for meaningful analysis. For non-TDEP patients, the 4-year OS for low, intermediate, high, and very high overall risk groups was 63%, 54%, 22%, and 18%, respectively (P < .0001). Our results confirm the prognostic value of the DRI in a cohort with a majority of TDEP patients.

Allogeneic hematopoietic stem cell transplantation in non-Hodgkin lymphoma in Switzerland, 30 years of experience: Sooner is better.

Due to relatively high nonrelapse mortality (NRM), allogeneic hematopoietic stem cell transplantation (allo-HSCT) in non-Hodgkin's lymphoma (NHL) remains the ultimate line of treatment but the only curable approach in a setting of relapse/refractory disease. Here, we conducted a retrospective, multicenter, registry-based analysis on patients who underwent allo-HSCT for NHL in Switzerland, over 30-year (1985-2020) period. The study included 301 allo-HSCTs performed for NHL patients in three University Hospitals of Switzerland (Zurich, Basel and Geneva) 09/1985 to 05/2020. We assessed in univariate and multivariable analysis the impact on survivals (overall survival [OS], relapse free survival [RFS], relapse incidence [RI], and non-treatment related mortality [NRM]). The maximum follow-up was 25 years with median follow-up for alive patients of 61 months. The median age at allo-HSCT was 51 years. Three- and -year OS was - 59.5% and 55.4%; 3- and 5-year PFS was 50% and 44%; 3- and 5-year NRM was 21.7% and 23.6%. RI at 3 and 5 years was 27.4% and 34.9%. In conclusion, our analysis of the entire Swiss experience of allo-HSCT in patients with NHL shows promising 5- and possibly 10-year OS and relatively acceptable NRM rates for such population, the majority being not in complete remission (CR) at the time of transplantation.

Rhinovirus Infections among Hematopoietic Stem Cell Transplant Recipients: A Pre-Transplant Dilemma?

Respiratory viral infections (RVIs) in allogeneic hematopoietic stem cell transplant (allo-HSCT) recipients can be of concern due to the patients' depressed immune status, but few data are available about the significance of a pre-transplant positive testing. In this retrospective observational study, we analyzed a cohort of patients that were transplanted between 1 January 2010 and 31 October 2019 in the Geneva University Hospitals with at least one RVI before or after transplantation. At least one RVI was detected in 319/533 (63.5%) transplanted patients. Rhinoviruses were most frequently identified (37%), followed by human coronaviruses (17.1%), parainfluenza viruses (13.9%), and influenza viruses (9.9%). First infection in the post-transplant period occurred at a mean time of 334 days (SD 338). Specific analysis of a subgroup of 65 patients with pre-transplant RVIs was performed. Among them, 39 (59%) patients had symptoms and 14 (21.2%) had a lower respiratory tract infection. Four patients (6.1%) (three rhinovirus and one influenza) needed an intensive care unit admission, of which, three (4.5%) (two rhinovirus and one influenza) were intubated. The patient with influenza infection diagnosed the day of the transplantation died within the first 30 days of the infection. Two patients with rhinovirus infection died within 3 months of unrelated causes. Our data show that rhinovirus infections are predominant in allo-HSCT patients, including among pre-transplant infections; however, mortality due to pre-transplant RVI is low and was only clearly identified in one patient with influenza infection. RVI within the month preceding allo-HSCT is not associated with direct morbidity or mortality in this cohort.

Defibrotide Shows Efficacy in the Prevention of Sinusoidal Obstruction Syndrome After Allogeneic Hematopoietic Stem Cell Transplantation: A Retrospective Study.

Sinusoidal obstruction syndrome (SOS), also known as hepatic veno-occlusive disease (VOD), is a well-known complication of allogeneic hematopoietic stem cell transplantation (HSCT) associated with a mortality rate of up to 85%.  Defibrotide has shown efficacy in treatment of SOS/VOD. Moreover, evidence exists supporting the efficacy of defibrotide as SOS/VOD prophylaxis. We have previously reported our single center experience on 52 HSCT recipients receiving defibrotide as SOS/VOD prophylaxis, which has shown that the patients did not develop any SOS/VOD under this prophylaxis. The aim of the present study was to see if we can confirm the previous results, mainly on the decrease incidence of SOS/VOD, as well as improve event-free survival (EFS) on a larger study population. We extended our previous study in a single-center retrospective analysis to include 237 consecutive patients (248 transplantations) who underwent transplantation between 1999 and 2009 for hematological diseases and receiving intravenous defibrotide as prophylaxis. This cohort was compared to 241 patients (248 transplantations) treated before 1999 or after 2009 when defibrotide prophylaxis was not routinely used in our center. Median follow-up for the study group was 10 (range 2-16) years and for the control group 2.7 (range 1-18) years. None of the 237 patients in the defibrotide group developed SOS/VOD. The cumulative incidence (CI) of SOS/VOD was 0% in the defibrotide group as compared to 4.8% (95% confidence interval [CI], 2.6-8%; P= .00046) in the control group. There was also a better 1-year EFS with 38% (95% CI, 32%-44%) in the defibrotide group versus 28% (95% CI, 22%-34%) (P= .00969) and decreased cumulative incidence of acute graft-versus-host disease (GvHD) in the defibrotide group 31% (95% CI, 25%-37%) versus 42% (95% CI, 36%-48%) (P= .026). The 1-year overall survival, relapse incidence, and non-relapse mortality were not statistically different. Multivariable analysis, performed taking into account clinical factors known to influence the risk of SOS/VOD, confirmed the favorable impact of defibrotide on SOS/VOD (HR 1.38e-08 [95% CI, 3.28e-09-5.80e-08]; P< .00001). Conversely, multivariable analysis failed to confirm the impact of defibrotide on 1-year EFS or acute GvHD. This large retrospective study on SOS/VOD-prophylaxis with defibrotide suggests that this approach may be of benefit. These results need to be confirmed in a prospective randomized trial.

CD56bright NK cells after hematopoietic stem cell transplantation are activated mature NK cells that expand in patients with low numbers of T cells.

We studied early NK-cell recovery in 29 allografted patients undergoing different lymphoreductive regimens. Already at 2 wk after graft take, the number of NK cells had reached (supra)normal levels but NK-cell subsets were skewed. The number of CD56(dim) CD16(bright) NK cells was low and correlated strongly with the level of hematopoiesis, whereas the number of the more abundant NK cells expressing high levels of CD56 did not. Post-transplant CD56(bright) NK cells (ptCD56(bright)) differed from CD56(bright) NK cells in normal controls (CD56(bright)) in being HLA-DR- and perforin-positive, CCR7(-), CD27(-), CD127(-) and mostly c-kit(-). CD56(bright) from normal controls stimulated by IL-15 in vitro (NK(IL-15)) acquired all the characteristics distinguishing CD56(bright) from ptCD56(bright). IL-2 exerted similar effects. Moreover, when cultured without cytokines, ptCD56(bright), CD56(bright) and NK(IL-15) responded similarly by upregulating CD127 and c-kit but not CCR7. IL-12 stimulated IFN-γ production in ptCD56(bright), whereas CD56(bright) responded only to IL-12 plus IL-15. Hence, ptCD56(bright) have all the features of cytokine-stimulated CD56(bright). Because only patients with low numbers of T cells had high numbers of ptCD56(bright), we conclude that ptCD56(bright) are activated CD56(bright) that expand while competing with T cells for the elevated post-transplant level of IL-15.

[How to capture cytogenetic and molecular abnormalities into ProMISe database for hematological malignancies: Guidelines from the francophone society of bone marrow transplantation and cellular therapy (SFGM-TC)]. / Modalités de capture des anomalies cytogénétiques et moléculaires pour la leucémie aiguë, le myélome multiple, le syndrome myélodysplasique, le syndrome myéloprolifératif et le syndrome myélodysplasique/myéloprolifératif : recommandations de la Société francophone de greffe de moelle et de thérapie cellulaire (SFGM-TC).

In an effort to standardize hematopoietic stem cell allograft procedures, the Francophone bone marrow transplantation and Cell Therapy Society (SFGM-TC) organized the 9th Allograft Harmonization Practice Workshop in Lille in September 2018. The purpose of these workshops is to propose a consensual attitude to the centers that wish it. In this workshop, we discuss how to capture the cytogenetic and molecular abnormalities of acute leukaemias, myelomas, myelodysplasias, myeloproliferative syndromes and myelodysplastic/myeloproliferative syndromes in the database common to all European transplant centers called ProMISe and managed by the European Society for Blood and Marrow Transplantation (EBMT). The complexity of cytogenetic and molecular data makes it difficult to enter data into the ProMISe registry. This workshop proposes a tool for input assistance, in tabular form by pathology. The main recommendation for the karyotype remains that of the complex karyotype that must be entered in "Full caryotype". Concerning the molecular anomalies, it is necessary to enter all the items proposed by ProMISe. In reviewing all the sheets proposed by ProMise, we note the absence of some relevant elements that can be added later.

Genetic T-cell receptor diversity at 1 year following allogeneic hematopoietic stem cell transplantation.

After allogeneic hematopoietic stem cell transplantation (HSCT), immune reconstitution leads to the development of a new T-cell repertoire. Immune reconstitution could be influenced by events such as conditioning, infections, and graft versus host disease (GVHD). Factors influencing the TCR diversity are of great interest to fine-tune the strategy for donor selection and to optimize standard of care. In this work, immunosequencing of the TCR CDR3ß region was carried out in a large cohort of 116 full chimeric recipients at 1 year post-HSCT and their respective donors prior to transplantation. The repertoire overlap before and after HSCT was minimal, supporting de novo reconstitution as a primary pathway at any age. Among the parameters investigated, increased patient and/or donor age as well as positive CMV serologic status reinforced by CMV infection/reactivation were the ones significantly associated with a reduced diversity at 1 year post-HSCT. CMV-specific T-cell clones were shown to influence the clonality of the repertoire alongside the expansion of limited numbers of non-CMV T-cell populations. Interestingly, at the exception of CMV infection/reactivation, TCR diversity was not predictive of GVHD, relapse, death, or infections post-HSCT.

Torque Teno Virus as a Potential Biomarker for Complications and Survival After Allogeneic Hematopoietic Stem Cell Transplantation.

Impaired immune reconstitution after allogeneic hematopoietic stem cell transplantation (HSCT) contributes to increased risk of cancer relapse and infection resulting in significant morbidity and mortality. Unfortunately, effective strategies to functionally assess the quality of immune reconstitution are still missing. Quantification of in vivo replication of the ubiquitous, non-pathogenic virus Torque Teno Virus (TTV) has been reported in small series as a test to functionally evaluate the quality of post-transplant immune reconstitution. In the present study, we analyzed by quantitative PCR TTV titers in plasma samples from a large cohort of 168 allogeneic HSCT recipients. Our analysis confirms that TTV titers peaked at 100 days post-transplant, followed by progressive normalization thereafter. Negative correlation of TTV titers with T cell absolute numbers during the first year post-transplant points to the restoration of an active anti-TTV immunity. Univariable and multivariable linear regression analysis demonstrated that donor CMV positive serostatus, donor type and immune suppression resulting from GVHD treatment affected the restoration of anti-TTV immunity. Importantly, higher TTV titers at 100 days after transplantation were associated with worse overall survival and higher risk of acute GVHD and infections. Our results provide new insights into the factors affecting the dynamics of TTV replication and indicate that TTV is a potentially useful biomarker to assess immune reconstitution and to predict complications and outcomes of allogeneic HSCT.

[Reporting data of patients receiving CAR T cell therapy into the EBMT registry: Guidelines of the Francophone Society of Bone Marrow Transplantation and Cellular Therapy (SFGM-TC)]. / Saisie des données des patients faisant l'objet d'un traitement par cellules CAR-T : recommandations de la Société Francophone de Greffe de Moelle et de Thérapie Cellulaire (SFGM-TC).

Tisagenlecleucel (Kymriah™) and axicabtagene ciloleucel (Yescarta™) are the first two approved drug products that belong to of a new class of therapies manufactured through an industrial process that includes the ex vivo genetic modification of human autologous T lymphocytes with viral vectors. Since CAR-T Cells qualify as gene therapy medicinal products, there is a requirement for long-term (15 years) follow-up of treated patients. As part of a global initiative aiming at a better use of continental registries to study the outcome of homogeneous groups of patients, EMA issued a positive opinion on the use of the EBMT registry to capture LTFU of patients treated with CAR-T Cell in EU Member states. The use of a European registry will provide a global view of this new field across EU countries and across diverse indications, and bears advantages over the use of registries dedicated to specific categories of diseases, or national registries. This is an important asset to fully measure the medical value of these innovative therapies in real-life conditions, and assess whether pricing is fully justified. To fulfill EMA requirements, as well as requirements from Pharma companies, EBMT has designed a new Cellular Therapy Med-A form that allows to capture the essential information on the administered drug product, disease and patient. Registering patients and capturing follow-up data is already possible in Promise, and will be made easier when the full migration of the EBMT database from Promise to MACRO is completed in the forthcoming weeks. Negotiations are ongoing with all interested parties including patients to define in which conditions data will be accessed and analyzed; the underlying principle is to favor rather than restrict the use of data, with a view to build cooperative projects involving relevant cooperative groups and professional associations. Here, we present practical recommendations issued by SFGM-TC to help data managers capture information related to patients treated with CAR-T Cells.

Dynamics of Expression of Programmed Cell Death Protein-1 (PD-1) on T Cells After Allogeneic Hematopoietic Stem Cell Transplantation.

Immune exhaustion contributes to treatment failure after allogeneic hematopoietic stem cell transplantation (HSCT) for hematological malignancies. Immune checkpoint blockade, including programmed cell death protein-1 (PD-1) blockade, is a promising strategy to improve the antitumor effect of allogeneic HSCT with high rates of response reported in patients treated for disease relapse. However, severe and sometimes fatal Graft- vs.-Host-Disease (GvHD) has been reported as a complication. Little is known about the dynamics of PD-1 expression on immune effector cells after allogeneic HSCT. In the present study, we analyzed PD-1 expression on T cell subpopulations isolated from 105 allogeneic HSCT recipients. Our analysis revealed a significant increase in proportions of PD-1-expressing CD4 and CD8 T cells early after allogeneic HSCT followed by a progressive normalization of PD-1 expression at CD8 but not CD4 T cell surface. Analysis of co-expression of two other exhaustion markers, 2B4 and CD160, revealed a preferential expansion of PD-1-single positive cells. Moreover, the analysis of granzyme B and perforin expression in PD-1+ and PD-1- CD8 T cells from HSCT recipients did not reveal any impairment in cytotoxic molecules production by PD-1-expressing CD8 T cells. Analyzing the association between clinical factors and the expression of PD-1 on T cells, we identified the use of in vivo and/or ex vivo T-cell depletion as the factor most strongly associated with elevated PD-1 levels on T cells. Our results extend our knowledge of the regulation of PD-1 expression at T cell surface after allogeneic HSCT, a crucial information for the optimization of post-transplantation PD-1 blocking therapies.

Partial T-cell depletion improves the composite endpoint graft-versus-host disease-free, relapse-free survival after allogeneic hematopoietic stem cell transplantation.

Graft-versus-host disease (GvHD)-free, relapse-free survival (GRFS) is a recently reported composite endpoint that allows to simultaneously estimate risk of death, relapse and GvHD after allogeneic hematopoietic stem cell transplantation (HSCT). In this retrospective study comprising 333 patients transplanted for hematologic malignancies, we compared GRFS in patients receiving partial T-cell-depleted (pTCD) grafts with patients receiving T-cell-replete grafts (No-TCD). pTCD was associated with a significantly improved GRFS. The beneficial effect of pTCD on GRFS remained highly significant in multivariable analysis taking into account clinical factors differing between patient groups. We observed no effect of pTCD on overall survival, progression-free survival, and relapse cumulative incidence, while non-relapse mortality cumulative incidence was significantly lower in patients receiving pTCD. The results of our retrospective analysis suggest that pTCD could improve GRFS in allogeneic HSCT recipients without significantly affecting OS and PFS, thus improving patients' quality of life without impairing the curative potential of allogeneic HSCT.

Cross-priming of cyclin B1, MUC-1 and survivin-specific CD8+ T cells by dendritic cells loaded with killed allogeneic breast cancer cells.

INTRODUCTION: The ability of dendritic cells (DCs) to take up whole tumor cells and process their antigens for presentation to T cells ('cross-priming') is an important mechanism for induction of tumor specific immunity. METHODS: In vitro generated DCs were loaded with killed allogeneic breast cancer cells and offered to autologous naïve CD8+ T cells in 2-week and/or 3-week cultures. CD8+ T cell differentiation was measured by their capacity to secrete effector cytokines (interferon-gamma) and kill breast cancer cells. Specificity was measured using peptides derived from defined breast cancer antigens. RESULTS: We found that DCs loaded with killed breast cancer cells can prime naïve CD8+ T cells to differentiate into effector cytotoxic T lymphocytes (CTLs). Importantly, these CTLs primed by DCs loaded with killed HLA-A*0201- breast cancer cells can kill HLA-A*0201+ breast cancer cells. Among the tumor specific CTLs, we found that CTLs specific for HLA-A2 restricted peptides derived from three well known shared breast tumor antigens, namely cyclin B1, MUC-1 and survivin. CONCLUSION: This ability of DCs loaded with killed allogeneic breast cancer cells to elicit multiantigen specific immunity supports their use as vaccines in patients with breast cancer.

IL-15-induced human DC efficiently prime melanoma-specific naive CD8+ T cells to differentiate into CTL.

Monocytes differentiate into dendritic cells (DC) in response to GM-CSF combined with other cytokines including IL-4 and IL-15. Here, we show that IL15-DC are efficient in priming naive CD8+ T cells to differentiate into melanoma antigen-specific cytotoxic T lymphocytes (CTL). While both melanoma peptide-pulsed IL15-DC and IL4-DC expand high-precursor frequency MART-1-specific CD8+ T cells after two stimulations in vitro, IL15-DC require much lower peptide concentration for priming. IL15-DC are more efficient in expanding gp100-specific CD8+ T cells and can expand CD8+ T cells specific for Tyrosinase and MAGE-3. CTL primed by IL15-DC are superior in their function as demonstrated by (i) higher IFN-gamma secretion, (ii) higher expression of Granzyme B and Perforin, and (iii) higher killing of allogeneic melanoma cell lines, most particularly the HLA-A*0201+ Sk-Mel-24 melanoma cells that are resistant to killing by CD8+ T cells primed with IL4-DC. Supernatants of the sonicated cells demonstrate unique expression of IL-1, IL-8 and IL-15. Therefore, membrane-bound IL-15 might contribute to enhanced priming by IL15-DC. Thus, IL-15 induces myeloid DC that are efficient in priming and maturation of melanoma antigen-specific CTL.

TNF skews monocyte differentiation from macrophages to dendritic cells.

Monocytes represent a large pool of circulating precursors of APCs, both macrophages and dendritic cells (DCs). It is thus important to identify the mechanisms by which microenvironment regulates monocyte differentiation. We have previously shown that, upon contact with resting stromal cells such as fibroblasts, monocytes differentiate into macrophages in an IL-6/M-CSF-dependent fashion. Yet, in the inflamed tissue, monocytes need to yield DCs for the adaptive immunity to be induced. Inasmuch as TNF and IL-1 are present at the site of inflammation, we tested their capacity to modulate monocyte differentiation into either macrophages or DCs. TNF, but not IL-1, induce monocytes to become DCs despite the presence of fibroblasts. TNF-induced DCs contain Langerin-positive cells and are able to induce allogenic T cell proliferation. Then, TNF was found to decrease the expression and internalization of the M-CSF receptor, thus overriding the IL-6/M-CSF pathway. Thus, TNF facilitates the induction of adaptive immunity by promoting DC differentiation not only from CD34+ progenitors but also from CD14+ blood precursors.