In vivo HSC prime editing rescues sickle cell disease in a mouse model.

Sickle cell disease (SCD) is a monogenic disease caused by a nucleotide mutation in the ß-globin gene. Current gene therapy studies are mainly focused on lentiviral vector-mediated gene addition or CRISPR/Cas9-mediated fetal globin reactivation, leaving the root cause unfixed. We developed a vectorized prime editing system that can directly repair the SCD mutation in hematopoietic stem cells (HSCs) in vivo in a SCD mouse model (CD46/Townes mice). Our approach involved a single intravenous injection of a nonintegrating, prime editor-expressing viral vector into mobilized CD46/Townes mice and low-dose drug selection in vivo. This procedure resulted in the correction of ∼40% of ßS alleles in HSCs. On average, 43% of sickle hemoglobin was replaced by adult hemoglobin, thereby greatly mitigating the SCD phenotypes. Transplantation in secondary recipients demonstrated that long-term repopulating HSCs were edited. Highly efficient target site editing was achieved with minimal generation of insertions and deletions and no detectable off-target editing. Because of its simplicity and portability, our in vivo prime editing approach has the potential for application in resource-poor countries where SCD is prevalent.

The diverse genetic origins of a Classical period Greek army.

Trade and colonization caused an unprecedented increase in Mediterranean human mobility in the first millennium BCE. Often seen as a dividing force, warfare is in fact another catalyst of culture contact. We provide insight into the demographic dynamics of ancient warfare by reporting genome-wide data from fifth-century soldiers who fought for the army of the Greek Sicilian colony of Himera, along with representatives of the civilian population, nearby indigenous settlements, and 96 present-day individuals from Italy and Greece. Unlike the rest of the sample, many soldiers had ancestral origins in northern Europe, the Steppe, and the Caucasus. Integrating genetic, archaeological, isotopic, and historical data, these results illustrate the significant role mercenaries played in ancient Greek armies and highlight how participation in war contributed to continental-scale human mobility in the Classical world.

Enhanced HbF reactivation by multiplex mutagenesis of thalassemic CD34+ cells in vitro and in vivo.

Thalassemia or sickle cell patients with hereditary persistence of fetal hemoglobin (HbF) have an ameliorated clinical phenotype and, in some cases, can achieve transfusion independence. Inactivation via genome editing of γ-globin developmental suppressors, such as BCL11A or LRF/ZBTB7A, or of their binding sites, have been shown to significantly increase expression of endogenous HbF. To broaden the therapeutic window beyond a single-editing approach, we have explored combinations of cis- and trans-editing targets to enhance HbF reactivation. Multiplex mutagenesis in adult CD34+ cells was well tolerated and did not lead to any detectable defect in the cells' proliferation and differentiation, either in vitro or in vivo. The combination of 1 trans and 1 cis mutation resulted in high editing retention in vivo, coupled with almost pancellular HbF expression in NBSGW mice. The greater in vivo performance of this combination was also recapitulated using a novel helper-dependent adenoviral-CRISPR vector (HD-Ad-dualCRISPR) in CD34+ cells from ß-thalassemia patients transplanted to NBSGW mice. A pronounced increase in HbF expression was observed in human red blood cells in mice with established predominant ß0/ß0-thalassemic hemopoiesis after in vivo injection of the HD-Ad-dualCRISPR vector. Collectively, our data suggest that the combination of cis and trans fetal globin reactivation mutations has the potential to significantly increase HbF both totally and on a per cell basis over single editing and could thus provide significant clinical benefit to patients with severe ß-globin phenotype.

Myasthenia gravis genome-wide association study implicates AGRN as a risk locus.

BACKGROUND: Myasthenia gravis (MG) is a rare autoimmune disorder affecting the neuromuscular junction (NMJ). Here, we investigate the genetic architecture of MG via a genome-wide association study (GWAS) of the largest MG data set analysed to date. METHODS: We performed GWAS meta-analysis integrating three different data sets (total of 1401 cases and 3508 controls). We carried out human leucocyte antigen (HLA) fine-mapping, gene-based and tissue enrichment analyses and investigated genetic correlation with 13 other autoimmune disorders as well as pleiotropy across MG and correlated disorders. RESULTS: We confirmed the previously reported MG association with TNFRSF11A (rs4369774; p=1.09×10-13, OR=1.4). Furthermore, gene-based analysis revealed AGRN as a novel MG susceptibility gene. HLA fine-mapping pointed to two independent MG loci: HLA-DRB1 and HLA-B. MG onset-specific analysis reveals differences in the genetic architecture of early-onset MG (EOMG) versus late-onset MG (LOMG). Furthermore, we find MG to be genetically correlated with type 1 diabetes (T1D), rheumatoid arthritis (RA), late-onset vitiligo and autoimmune thyroid disease (ATD). Cross-disorder meta-analysis reveals multiple risk loci that appear pleiotropic across MG and correlated disorders. DISCUSSION: Our gene-based analysis identifies AGRN as a novel MG susceptibility gene, implicating for the first time a locus encoding a protein (agrin) that is directly relevant to NMJ activation. Mutations in AGRN have been found to underlie congenital myasthenic syndrome. Our results are also consistent with previous studies highlighting the role of HLA and TNFRSF11A in MG aetiology and the different risk genes in EOMG versus LOMG. Finally, we uncover the genetic correlation of MG with T1D, RA, ATD and late-onset vitiligo, pointing to shared underlying genetic mechanisms.

Precision Editing as a Therapeutic Approach for ß-Hemoglobinopathies.

Beta-hemoglobinopathies are the most common genetic disorders worldwide, caused by a wide spectrum of mutations in the ß-globin locus, and associated with morbidity and early mortality in case of patient non-adherence to supportive treatment. Allogeneic transplantation of hematopoietic stem cells (allo-HSCT) used to be the only curative option, although the indispensable need for an HLA-matched donor markedly restricted its universal application. The evolution of gene therapy approaches made possible the ex vivo delivery of a therapeutic ß- or γ- globin gene into patient-derived hematopoietic stem cells followed by the transplantation of corrected cells into myeloablated patients, having led to high rates of transfusion independence (thalassemia) or complete resolution of painful crises (sickle cell disease-SCD). Hereditary persistence of fetal hemoglobin (HPFH), a syndrome characterized by increased γ-globin levels, when co-inherited with ß-thalassemia or SCD, converts hemoglobinopathies to a benign condition with mild clinical phenotype. The rapid development of precise genome editing tools (ZFN, TALENs, CRISPR/Cas9) over the last decade has allowed the targeted introduction of mutations, resulting in disease-modifying outcomes. In this context, genome editing tools have successfully been used for the introduction of HPFH-like mutations both in HBG1/HBG2 promoters or/and in the erythroid enhancer of BCL11A to increase HbF expression as an alternative curative approach for ß-hemoglobinopathies. The current investigation of new HbF modulators, such as ZBTB7A, KLF-1, SOX6, and ZNF410, further expands the range of possible genome editing targets. Importantly, genome editing approaches have recently reached clinical translation in trials investigating HbF reactivation in both SCD and thalassemic patients. Showing promising outcomes, these approaches are yet to be confirmed in long-term follow-up studies.

Pre-Emptive Use of Rituximab in Epstein-Barr Virus Reactivation: Incidence, Predictive Factors, Monitoring, and Outcomes.

Post-transplant lymphoproliferative disease (PTLD) is a fatal complication of hematopoietic cell transplantation (HCT) associated with the Epstein-Barr virus (EBV). Multiple factors such as transplant type, graft-versus-host disease (GVHD), human leukocyte antigens (HLA) mismatch, patient age, and T-lymphocyte-depleting treatments increase the risk of PTLD. EBV reactivation in hematopoietic cell transplant recipients is monitored through periodic quantitative polymerase chain reaction (Q-PCR) tests. However, substantial uncertainty persists regarding the clinically significant EBV levels for these patients. Guidelines recommend initiating EBV monitoring no later than four weeks post-HCT and conducting it weekly. Pre-emptive therapies, such as the reduction of immunosuppressive therapy and the administration of rituximab to treat EBV viral loads are also suggested. In this study, we investigated the occurrence of EBV-PTLD in 546 HCT recipients, focusing on the clinical manifestations and risk factors associated with the disease. We managed to identify 67,150 viral genomic copies/mL as the cutoff point for predicting PTLD, with 80% sensitivity and specificity. Among our cohort, only 1% of the patients presented PTLD. Anti-thymocyte globulin (ATG) and GVHD were independently associated with lower survival rates and higher treatment-related mortality. According to our findings, prophylactic measures including regular monitoring, pre-emptive therapy, and supportive treatment against infections can be effective in preventing EBV-related complications. This study also recommends conducting EBV monitoring at regular intervals, initiating pre-emptive therapy when viral load increases, and identifying factors that increase the risk of PTLD. Our study stresses the importance of frequent and careful follow-ups of post-transplant complications and early intervention in order to improve survival rates and reduce mortality.

Soluble Urokinase-Type Plasminogen Activator Receptor (suPAR) and Growth Differentiation Factor-15 (GDF-15) Levels Are Significantly Associated with Endothelial Injury Indices in Adult Allogeneic Hematopoietic Cell Transplantation Recipients.

Hematopoietic stem cell transplantation-associated thrombotic microangiopathy (HSCT-TMA) and graft-versus-host disease (GvHD) represent life-threatening syndromes after allogeneic hematopoietic stem cell transplantation (allo-HSCT). In both conditions, endothelial dysfunction is a common denominator, and development of relevant biomarkers is of high importance for both diagnosis and prognosis. Despite the fact that soluble urokinase plasminogen activator receptor (suPAR) and growth differentiation factor-15 (GDF-15) have been determined as endothelial injury indices in various clinical settings, their role in HSCT-related complications remains unexplored. In this context, we used immunoenzymatic methods to measure suPAR and GDF-15 levels in HSCT-TMA, acute and/or chronic GVHD, control HSCT recipients, and apparently healthy individuals of similar age and gender. We found considerably greater SuPAR and GDF-15 levels in HSCT-TMA and GVHD patients compared to allo-HSCT and healthy patients. Both GDF-15 and suPAR concentrations were linked to EASIX at day 100 and last follow-up. SuPAR was associated with creatinine and platelets at day 100 and last follow-up, while GDF-15 was associated only with platelets, suggesting that laboratory values do not drive EASIX. SuPAR, but not GDF-15, was related to soluble C5b-9 levels, a sign of increased HSCT-TMA risk. Our study shows for the first time that suPAR and GDF-15 indicate endothelial damage in allo-HSCT recipients. Rigorous validation of these biomarkers in many cohorts may provide utility for their usefulness in identifying and stratifying allo-HSCT recipients with endothelial cell impairment.

In Vivo HSC Gene Therapy Using a Bi-modular HDAd5/35++ Vector Cures Sickle Cell Disease in a Mouse Model.

We have recently reported that, after in vivo hematopoietic stem cell/progenitor (HSPC) transduction with HDAd5/35++ vectors, SB100x transposase-mediated γ-globin gene addition achieved 10%-15% γ-globin of adult mouse globin, resulting in significant but incomplete phenotypic correction in a thalassemia intermedia mouse model. Furthermore, genome editing of a γ-globin repressor binding site within the γ-globin promoter by CRISPR-Cas9 results in efficient reactivation of endogenous γ-globin. Here, we aimed to combine these two mechanisms to obtain curative levels of γ-globin after in vivo HSPC transduction. We generated a HDAd5/35++ adenovirus vector (HDAd-combo) containing both modules and tested it in vitro and after in vivo HSPC transduction in healthy CD46/ß-YAC mice and in a sickle cell disease mouse model (CD46/Townes). Compared to HDAd vectors containing either the γ-globin addition or the CRISPR-Cas9 reactivation units alone, in vivo HSC transduction of CD46/Townes mice with the HDAd-combo resulted in significantly higher γ-globin in red blood cells, reaching 30% of that of adult human α and ßS chains and a complete phenotypic correction of sickle cell disease.

Vaccinated and Convalescent Donor-Derived Severe Acute Respiratory Syndrome Coronavirus 2-Specific T Cells as Adoptive Immunotherapy for High-Risk Coronavirus Disease 2019 Patients.

BACKGROUND: The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic poses an urgent need for the development of effective therapies for coronavirus disease 2019 (COVID-19). METHODS: We first tested SARS-CoV-2-specific T-cell (CοV-2-ST) immunity and expansion in unexposed donors, COVID-19-infected individuals (convalescent), asymptomatic polymerase chain reaction (PCR)-positive subjects, vaccinated individuals, non-intensive care unit (ICU) hospitalized patients, and ICU patients who either recovered and were discharged (ICU recovered) or had a prolonged stay and/or died (ICU critical). CoV-2-STs were generated from all types of donors and underwent phenotypic and functional assessment. RESULTS: We demonstrate causal relationship between the expansion of endogenous CoV-2-STs and the disease outcome; insufficient expansion of circulating CoV-2-STs identified hospitalized patients at high risk for an adverse outcome. CoV-2-STs with a similarly functional and non-alloreactive, albeit highly cytotoxic, profile against SARS-CoV-2 could be expanded from both convalescent and vaccinated donors generating clinical-scale, SARS-CoV-2-specific T-cell products with functional activity against both the unmutated virus and its B.1.1.7 and B.1.351 variants. In contrast, critical COVID-19 patient-originating CoV-2-STs failed to expand, recapitulating the in vivo failure of CoV-2-specific T-cell immunity to control the infection. CoV-2-STs generated from asymptomatic PCR-positive individuals presented only weak responses, whereas their counterparts originating from exposed to other seasonal coronaviruses subjects failed to kill the virus, thus disempowering the hypothesis of protective cross-immunity. CONCLUSIONS: Overall, we provide evidence on risk stratification of hospitalized COVID-19 patients and the feasibility of generating powerful CoV-2-ST products from both convalescent and vaccinated donors as an "off-the shelf" T-cell immunotherapy for high-risk patients.

Non-transplantable cord blood units as a source for adoptive immunotherapy of leukaemia and a paradigm of circular economy in medicine.

Advances in immunotherapy with T cells armed with chimeric antigen receptors (CAR-Ts), opened up new horizons for the treatment of B-cell lymphoid malignancies. However, the lack of appropriate targetable antigens on the malignant myeloid cell deprives patients with refractory acute myeloid leukaemia of effective CAR-T therapies. Although non-engineered T cells targeting multiple leukaemia-associated antigens [i.e. leukaemia-specific T cells (Leuk-STs)] represent an alternative approach, the prerequisite challenge to obtain high numbers of dendritic cells (DCs) for large-scale Leuk-ST generation, limits their clinical implementation. We explored the feasibility of generating bivalent-Leuk-STs directed against Wilms tumour 1 (WT1) and preferentially expressed antigen in melanoma (PRAME) from umbilical cord blood units (UCBUs) disqualified for allogeneic haematopoietic stem cell transplantation. By repurposing non-transplantable UCBUs and optimising culture conditions, we consistently produced at clinical scale, both cluster of differentiation (CD)34+ cell-derived myeloid DCs and subsequently polyclonal bivalent-Leuk-STs. Those bivalent-Leuk-STs contained CD8+ and CD4+ T cell subsets predominantly of effector memory phenotype and presented high specificity and cytotoxicity against both WT1 and PRAME. In the present study, we provide a paradigm of circular economy by repurposing unusable UCBUs and a platform for future banking of Leuk-STs, as a 'third-party', 'off-the-shelf' T-cell product for the treatment of acute leukaemias.

Isolated Extramedullary Relapse as a Poor Predictor of Survival after Allogeneic Hematopoietic Cell Transplantation for Acute Leukemia.

Limited and conflicting data exist on outcomes of patients with extramedullary relapses (EMRs) after allogeneic hematopoietic cell transplantation (allo-HCT) for acute leukemias. We retrospectively reviewed charts of consecutive allo-HCT recipients who underwent transplantation in our center with the indication of acute leukemia (July 1990 to July 2018). Incidences of isolated EMR (iEMR) and bone marrow relapse (BMR) were calculated using cumulative incidence (CI) analysis, with each and treatment-related mortality considered a competing risk. We studied 554 allo-HCT recipients for 1.8 years (range, .04 to 27.75). Ten-year CI of 10.5% for iEMR was associated only with advanced disease phase at transplantation, whereas 10-year CI of 34.8% for BMR was independently associated with pretransplant disease phase, lines of treatment, and fungal infections. Most iEMR and BMR patients (75% and 81%, respectively) received systemic treatment combined with local radiation for iEMR (26%) and donor lymphocyte infusions (16% and 28%, respectively) when feasible. Extensive chronic graft-versus-host disease (GVHD) was recorded in 47% of iEMR and 48% of BMR patients. Outcomes were poor both in iEMR (10-year overall survival [OS], 18.3%) and BMR (10-year OS, 19.1%). Independent predictors of OS were disease phase, type of donor, acute and chronic GVHD, fungal infections, iEMR, and BMR. In a large population with long-term follow-up, incidence of iEMR was relatively high, developed at the late post-transplant period, and was associated only with disease phase at transplantation. Furthermore, iEMR and BMR conferred similarly poor outcomes despite systemic treatment or extensive chronic GVHD.

Genetic history of the population of Crete.

The medieval history of several populations often suffers from scarcity of contemporary records resulting in contradictory and sometimes biased interpretations by historians. This is the situation with the population of the island of Crete, which remained relatively undisturbed until the Middle Ages when multiple wars, invasions, and occupations by foreigners took place. Historians have considered the effects of the occupation of Crete by the Arabs (in the 9th and 10th centuries C.E.) and the Venetians (in the 13th to the 17th centuries C.E.) to the local population. To obtain insights on such effects from a genetic perspective, we studied representative samples from 17 Cretan districts using the Illumina 1 million or 2.5 million arrays and compared the Cretans to the populations of origin of the medieval conquerors and settlers. Highlights of our findings include (1) small genetic contributions from the Arab occupation to the extant Cretan population, (2) low genetic contribution of the Venetians to the extant Cretan population, and (3) evidence of a genetic relationship among the Cretans and Central, Northern, and Eastern Europeans, which could be explained by the settlement in the island of northern origin tribes during the medieval period. Our results show how the interaction between genetics and the historical record can help shed light on the historical record.

Aspergillus galactomannan detection: Trichoderma as a cause of positive results.

Aspergillus galactomannan immunoassay is a main diagnostic and monitoring tool in medical mycology. However, the specificity of the method can be skewered by the presence of several other fungi. Trying to diagnose a possible fungal infection of the lower respiratory tract in a haematology patient, it appeared that the fungus Trichoderma longibrachiatum is an additional probable cause of positive galactomannan results. Although, that Trichoderma is a rare but emerging pathogen in immunocompromised patients, the above information could be a caution point in the clinical evaluation of diagnostic results.

The ex vivo toll-like receptor 7 tolerance induction in donor lymphocytes prevents murine acute graft-versus-host disease.

BACKGROUND AIMS: Acute graft-versus-host disease (aGVHD) remains a major cause of morbidity and mortality after allogeneic hematopoietic stem cell transplantation, mediated by alloreactive donor T cells. Toll-like receptors (TLRs), a family of conserved pattern-recognition receptors (PRRs), represent key players in donors' T-cell activation during aGVHD; however, a regulatory, tolerogenic role for certain TLRs has been recognized in a different context. We investigated whether the ex vivo-induced TLR-2,-4,-7 tolerance in donor cells could prevent alloreactivity in a mismatched transplantation model. METHODS: TLR-2,-4,-7 tolerance was induced in mouse splenocytes, after stimulation with low doses of corresponding ligands. Cellular and molecular changes of the TLR-tolerant splenocytes and purified T cells were assessed by immunophenotypic and gene expression analyses. Incidence of aGVHD was evaluated by the clinical score and survival as well as histopathology of target tissues. RESULTS: Only the R848-induced TLR7 tolerance prevented aGVHD. The TLR7 ligand-induced tolerance lasted for a critical post-transplant period and was associated with distinct cellular and molecular signatures characterized by induction of regulatory T cells, reduced alloreactivity and balanced regulation of inflammatory signaling and innate immune responses. The TLR7-tolerant T cells preserved the immunological memory and generated in vitro virus-specific T cells upon antigen stimulation. The anti-aGVHD tolerization effect was direct and specific to TLR7 and required the receptor-ligand interaction; TLR7-/- T cells isolated from B6 TLR7-/- mice presented a distinct gene expression profile but failed to prevent aGVHD. DISCUSSION: We propose an effective and clinically applicable ex vivo approach for aGVHD prevention through a transient and reversible immune reprogramming exerted by TLR7-tolerant donor lymphocytes.

Long-term outcomes of total body irradiation plus cyclophosphamide versus busulfan plus cyclophosphamide as conditioning regimen for acute lymphoblastic leukemia: a comparative study.

The role of total body irradiation (TBI) in allogeneic hematopoietic stem cell transplantation (HCT) for adult acute lymphoblastic leukemia (ALL) remains controversial. Therefore, we investigated long-term treatment outcomes of transplanted ALL patients aiming to identify prognostic factors and the impact of conditioning. We enrolled consecutive ALL patients transplanted from 1990 to 2016, following TBI- or busulfan (Bu)-based conditioning regimen. We studied 151 ALL patients transplanted in first complete remission (CR) (60), other CR (33), or relapsed/refractory disease (58) from sibling (87), and HLA-matched (42) or mismatched (17) unrelated and alternative donors (5). High-dose fractionated TBI-based conditioning was administered in 84. No differences were observed in baseline characteristics, except for disease stage at transplant, donor type, and graft source. With a follow-up of 19.0 (0.5-170.5) in TBI and 14.5 (1.2-319.1) months in non-TBI patients, there was no difference in acute (grades II-IV) or chronic GVHD, thrombotic microangiopathy, and bacterial or fungal infections. Only viral infections were significantly increased in the non-TBI group. There was no significant difference in the cumulative incidence (CI) of treatment-related or relapse mortality and disease-free or overall survival (OS). In the multivariate analysis, unfavorable pre-transplant predictors of OS were age (p = 0.024), advanced disease stage (p = 0.007), and female-to-male donor (p = 0.006). Interestingly, TBI patients younger than 40 years had significantly higher OS (55.1%, p = 0.023) and DFS (48.6%, p = 0.020). In conclusion, high-dose TBI is feasible in younger patients providing better survival. The choice between TBI- or Bu-conditioning regimens remains challenging.

Transplant-associated thrombotic microangiopathy: Incidence, prognostic factors, morbidity, and mortality in allogeneic hematopoietic cell transplantation.

Renewed interest has emerged in transplant-associated thrombotic microangiopathy (TA-TMA) with novel prognostic, diagnostic, and treatment algorithms. We aimed to investigate the incidence, prognostic factors, morbidity, and mortality of TA-TMA in allogeneic hematopoietic cell transplantation (HCT) recipients. We enrolled consecutive HCT recipients (1990-2017). Among 758 patients, 116 (15.5%) were diagnosed with TA-TMA. In the multivariate analysis, TBI-based conditioning, viral infections, acute and chronic GVHD remained independent predictors of TA-TMA. With a median follow-up of 23 (range 0.1-329) months, TA-TMA resulted in significantly lower overall survival (OS). In the multivariate analysis, TA-TMA remained an independent predictor of OS, along with relapse, acute, and chronic GVHD. Among 116 TA-TMA patients, 70 developed renal (56) and/or neurologic (26) dysfunction that would be necessary for TA-TMA diagnosis according to the Bone Marrow Transplant Clinical Trials Network criteria. TA-TMA patients with renal dysfunction showed increased rates of acute GVHD, but no difference in OS compared to patients without renal dysfunction. However, neurologic dysfunction resulted in significantly lower OS. In conclusion, TA-TMA is associated with increased morbidity and mortality in allogeneic transplant recipients. Successful prevention and treatment strategies of infections and GVHD need to be timely employed to improve survival in this complex setting.

Favorable impact of extracorporeal photopheresis in acute and chronic graft versus host disease: Prospective single-center study.

BACKGROUND: Graft vs host disease (GVHD) is the most severe complication of allogeneic hematopoietic cell transplantation. Conventional immunosuppressive therapy increases morbidity and mortality without improving survival. Extracorporeal photopheresis (ECP) has been introduced as an alternative treatment in steroid-dependent and steroid-refractory disease. STUDY DESIGN AND METHODS: We studied the safety and efficacy of ECP as a second- or third-line treatment in GVHD. RESULTS: ECP was administered in 21 patients with grade III-IV acute GVHD and 88 patients with extensive chronic GVHD, without ECP-related adverse events. Eight patients receiving four or less ECP sessions were not further analyzed. The majority of acute GVHD patients (84%) presented partial (15) or complete (1) response to ECP. Immunosuppression was reduced in 10 of 19 patients and ceased in 1 of 19 patients. One-year cumulative incidence (CI) of transplant-related mortality (TRM) (17.6%) was associated with the lack of response to ECP and steroid refractoriness. With a follow-up of 17.5 (1.8-58.3) months, 1-year overall survival (OS) (52.5%) was independently associated with a higher number of ECP sessions. Regarding chronic GVHD, complete response was achieved in 35 patients, whereas partial response in 25 patients, leading to an overall response rate of 73%. Cutaneous sclerosis manifestations were associated with higher response rates. With a follow-up of 68.1 (5.4-283.1) months, 5-year CI of TRM (24.1%) was associated only with a number of ECP sessions. The 5-year OS (64.5%) was independently associated with number of ECP sessions and cutaneous manifestations. CONCLUSION: Our findings suggest that ECP is safe and effective for GVHD and should be considered early in the course of GVHD, before irreversible end-organ damage has been established.

Survival Advantage and Comparable Toxicity in Reduced-Toxicity Treosulfan-Based versus Reduced-Intensity Busulfan-Based Conditioning Regimen in Myelodysplastic Syndrome and Acute Myeloid Leukemia Patients after Allogeneic Hematopoietic Cell Transplantation.

Treosulfan has been incorporated in conditioning regimens for sustained remission without substantial toxicity and treatment-related mortality (TRM). We aimed to analyze the safety and efficacy of a fludarabine 150 mg/m2 and treosulfan 42 g/m2 (FluTreo) conditioning regimen in medically infirm patients. Outcomes were compared with those of a similar historical group treated with fludarabine 150 mg/m2 to 180 mg/m2, busulfan 6.4 mg/kg, and antithymocyte globulin (ATG) 5 mg/kg to 7.5 mg/kg (FluBuATG). Thirty-one consecutive patients with acute myeloid leukemia (AML; n = 21), myelodysplastic syndrome (MDS; n = 6), or treatment-related AML (n = 4) received FluTreo conditioning. The historical group consisted of 26 consecutive patients treated with FluBuATG. In the FluTreo group, engraftment was prompt in all patients and 74% achieved >99% donor chimerism by day +30. No grades III or IV organ toxicities were noted. One-year cumulative incidences (CI) of acute and chronic graft-versus-host disease (GVHD) were 19.4% and 58.4%. The groups were similar for age, disease risk, lines of treatment, hematopoietic cell transplantation-specific comorbidity index, and acute or chronic GVHD incidence, except that there were more matched unrelated donor recipients in the FluTreo group (P < .001). With 20 (range, 2 to 36) months follow-up for FluTreo and 14 (range, 2 to 136) for FluBuATG, the 1-year cumulative overall survival (OS) probability was 76% versus 57%, respectively (P = .026); 1-year disease-free survival (DFS) was 79% versus 38% (P < .001). In multivariate analysis, the only significantly favorable factor for OS and DFS was FluTreo (P = .010 and P = .012). The CI of relapse mortality was markedly decreased in FluTreo versus FluBuATG (7.4% versus 42.3%, P < .001). In conclusion, the treosulfan-based regimen resulted in favorable OS and DFS with acceptable toxicity and low relapse rates compared with busulfan-based conditioning.

Plerixafor+G-CSF-mobilized CD34+ cells represent an optimal graft source for thalassemia gene therapy.

Globin gene therapy requires abundant numbers of highly engraftable, autologous hematopoietic stem cells expressing curative levels of ß-globin on differentiation. In this study, CD34+ cells from 31 thalassemic patients mobilized with hydroxyurea+granulocyte colony-stimulating factor (G-CSF), G-CSF, Plerixafor, or Plerixafor+G-CSF were transduced with the TNS9.3.55 ß-globin lentivector and compared for transducibility and globin expression in vitro, as well as engraftment potential in a xenogeneic model after partial myeloablation. Transduction efficiency and vector copy number (VCN) averaged 48.4 ± 2.8% and 1.91 ± 0.04, respectively, whereas expression approximated the one-copy normal ß-globin output. Plerixafor+G-CSF cells produced the highest ß-globin expression/VCN. Long-term multilineage engraftment and persistent VCN and vector expression was encountered in all xenografted groups, with Plerixafor+G-CSF-mobilized cells achieving superior short-term engraftment rates, with similar numbers of CD34+ cells transplanted. Overall, Plerixafor+G-CSF not only allows high CD34+ cell yields but also provides increased ß-globin expression/VCN and enhanced early human chimerism under nonmyeloablative conditions, thus representing an optimal graft for thalassemia gene therapy.