Poor prognosis of SRSF2 gene mutations in patients treated with VEN-AZA for newly diagnosed acute myeloid leukemia

Mutations in spliceosome genes (SRSF2, SF3B1, U2AF1, ZRSR2) correlate with inferior outcomes in patients treated with intensive chemotherapy for Acute Myeloid Leukemia. However, their prognostic impact in patients treated with less intensive protocols is not well known. This study aimed to evaluate the impact of Spliceosome mutations in patients treated with Venetoclax and Azacitidine for newly diagnosed AML. 117 patients treated in 3 different hospitals were included in the analysis. 34 harbored a mutation in at least one of the spliceosome genes (splice-mut cohort). K/NRAS mutations were more frequent in the splice-mut cohort (47% vs 19%, p=0.0022). Response rates did not differ between splice-mut and splice-wt cohorts. With a median follow-up of 15 months, splice mutations were associated with a lower 18-month LFS (p=0.0045). When analyzing splice mutations separately, we found SRSF2 mutations to be associated with poorer outcomes (p=0.034 and p=0.037 for OS and LFS respectively). This negative prognostic impact remained true in our multivariate analysis. We believe this finding should warrant further studies aimed at overcoming this negative impact.

Transplantation for myelofibrosis patients in the ruxolitinib era: a registry study from the Société Francophone de Greffe de Moelle et de Thérapie Cellulaire

In this SFGM-TC registry study, we report the results after stem cell transplantation (HSCT) in 305 myelofibrosis patients, in order to determine potential risk factors associated with outcomes, especially regarding previous treatment with ruxolitinib. A total of 102 patients were transplanted from an HLA-matched-sibling donor (MSD), and 143 patients received ruxolitinib. In contrast with previous studies, our results showed significantly worse outcomes for ruxolitinib patients regarding overall survival (OS) and non-relapse mortality (NRM), especially in the context of unrelated donors (URD). When exploring reasons for potential confounders regarding the ruxolitinib effect, an interaction between the type of donor and the use of ATG was found, therefore subsequent analyses were performed separately for each type of donor. Multivariable analyses did not confirm a significant negative impact of ruxolitinib in transplantation outcomes. In the setting of URD, only age and Fludarabine-Melphalan (FM) conditioning were associated with increased NRM. For MSD, only Karnoksfy <70% was associated with reduced OS. However, a propensity score analysis showed that ruxolitinib had a negative impact on OS but only in non-responding patients, consistent with previous data. To conclude, with all the precautions due to confounders and bias, ruxolitinib itself does not appear to increase mortality after HSCT.

Improving nutritional status after allogeneic stem cell transplantation: results of phase 2 ALLONUT clinical trial

Malnutrition increases the risk of non-relapse mortality after allogeneic stem cell transplantation (aHSCT). Here are the results of the ALLONUT clinical trial designed to improve the nutritional outcome of patients receiving aHSCT. ALLONUT is a prospective open label phase 2 clinical trial assessing the efficacy of a close tailored nutritional support and management with traditional and original solutions to improve patients nutritional status following aHSCT. Nutritional status evaluation was performed before transplantation, on Day 0, 30, 100 and one year after transplantation. The study involved 70 patients treated by aHSCT. 10% of patients were moderately or severely malnutrition at baseline and 26.9 were severely malnutrition at D30. Patients' nutritional status improved thanks to the cooking classes and the personalized outpatient nutrition program. At D100, 23% were still malnutrition, while only 10.8% were severely malnutrition one year after transplantation. The QLQ-C30 show that quality of life (QoL) decreased until D30, and improve to reach the pre-transplant level on D100 before exceeding it on D360. The study confirmed that a close, personalized nutritional program combining traditional and original measures can improve both nutritional status and QoL for patients suffering from moderate or severe malnutrition after aHCST.

Treosulfan compared to busulfan in allogeneic haematopoietic stem cell transplantation for myelofibrosis: a registry-based study from the Chronic Malignancies Working Party of the EBMT

We aimed to compare outcomes following treosulfan (TREO) or busulfan (BU) conditioning in a large cohort of myelofibrosis (MF) patients from the EBMT registry. A total of 530 patients were included; 73 received TREO and 457 BU (BU ≤ 6.4 mg/kg in 134, considered RIC, BU > 6.4 mg/kg in 323 considered higher dose (HD)). Groups were compared using adjusted Cox models. Cumulative incidences of engraftment and acute GVHD were similar across the 3 groups. The TREO group had significantly better OS than BU-HD (HR:0.61, 95% CI: 0.39-0.93) and a trend towards better OS over BU-RIC (HR: 0.66, 95% CI: 0.41-1.05). Moreover, the TREO cohort had a significantly better Progression-Free-Survival (PFS) than both the BU-HD (HR: 0.57, 95% CI: 0.38-0.84) and BU-RIC (HR: 0.60, 95% CI: 0.39-0.91) cohorts, which had similar PFS estimates. Non-relapse mortality (NRM) was reduced in the TREO and BU-RIC cohorts (HR: 0.44, 95% CI: 0.24-0.80 TREO vs BU-HD; HR: 0.54, 95% CI: 0.28-1.04 TREO vs BU-RIC). Of note, relapse risk did not significantly differ across the three groups. In summary, within the limits of a registry-based study, TREO conditioning may improve PFS in MF HSCT and have lower NRM than BU-HD with a similar relapse risk to BU-RIC. Prospective studies are needed to confirm these findings.

Comparison of clinical outcomes of several risk stratification tools in newly diagnosed AML patients: A real-world evidence in our current therapeutic era

BACKGROUND OF THE STUDY

AML classification tools have been developed to stratify the risk at AML diagnosis. There is a need to evaluate these tools in the current therapeutic era.

COHORT CHARACTERISTICS

In this retrospective study, we compared five classifiers: ELN 2017, ELN 2022, ALFA classifier, Papaemmanuil et al. classifier, and Lindsley et al. classifier, in a real-life cohort of 281 patients newly diagnosed for AML in Nice University Hospital. In our cohort median age was 68 years old, sex ratio was M/F 56%/44%, performance status was lower than 2 in 73.1% of patients, AML subtype was "De novo" in 71.5%, "secondary" in 22.4%, and "therapy-related" in 6.0% of patients. Intensive chemotherapy was used in 53.0% of patients, and non-intensive chemotherapy in 40.6% of patients. Molecular analysis was available in a large majority of patients and the main mutations found were NPM1 (22.7%), DNMT3A (17.4%), TP53 (13.1%), TET2 (12.4%), and FLT3-ITD (12.4%).

RESULTS

In our findings, the comparison of overall survival between the three prognostic groups in the global cohort was statistically significant in all classifiers: ELN 2017 p < 0.0001, ELN 2022 p < 0.0001, ALFA classifier p < 0.0001, Papaemmanuil classifier p < 0.0001, Lindsley classifier p = 0.001. ELN 2017, ELN 2022, ALFA classifier, Papaemmanuil classifier, and Lindsley classifier were calculated respectively in 99%, 99%, 89%, 90%, and 89% of patients.

CONCLUSIONS

Using Akaike's information criteria (AIC) to compare all five classifiers, ELN 2022 is the best classifier into younger and older patients and for prognosis.

[Secondary cancers following allogeneic hematopoietic stem cell transplantation: Guidelines from the Francophone Society of Bone Marrow Transplantation and Cellular Therapy (SFGM-TC)]

The Francophone Society of Bone Marrow Transplantation and Cellular Therapy (SFGM-TC) held the 13th edition of the Clinical Practices Harmonization Workshops. Our workgroup reviewed the current data on the incidence, screening methods and international guidelines for the prevention of secondary solid cancers following allogeneic hematopoietic stem cell transplantation. The purpose of this workshop was to provide recommendations for the screening and prevention of secondary malignancies to Francophone transplantation centers.

Efficacy of an antimicrobial stewardship intervention for early adaptation of antibiotic therapy in high-risk neutropenic patients

BACKGROUND

The 4th European Conference on Infections in Leukemia recommends early adaptation of empirical antibiotic therapy (EAT) for febrile neutropenia in stable patients.

OBJECTIVES

To assess the efficacy of an antimicrobial stewardship (AMS) intervention promoting early de-escalation and discontinuation of EAT in high-risk neutropenic patients.

METHODS

This before-after study was conducted in the hematology department of the University Hospital of Nice, France. The AMS intervention included the development of clinical decision support algorithms, a twice-weekly face-to-face review of all antibiotic prescriptions and monthly feedback on the intervention. The primary endpoint was overall antibiotic consumption during hospital stay, expressed as days of therapy (DOT).

RESULTS

A total of 113 admissions were included: 56 during the pre-intervention period and 57 during the intervention period. Induction chemotherapy and conditioning for allogeneic stem cell transplantation were the most frequent reasons for admission. In the intervention period, there was a significant decrease in overall antibiotic consumption (median DOT 20 vs. 28 days, p = 0.006), carbapenem consumption (median DOT 5.5 vs. 9 days, p = 0.017) and anti-resistant Gram-positive agents consumption (median DOT 8 vs. 11.5 days, p = 0.017). We found no statistical difference in the rates of intensive care unit admission (9% in each period) and 30-day mortality (5% vs. 0%, p = 0.243). Compliance with de-escalation and discontinuation strategies was significantly higher in the intervention period (77% vs. 8%, p < 0.001).

CONCLUSION

A multifaceted AMS intervention led to high compliance with early de-escalation and discontinuation of EAT and lower overall antibiotic consumption, without negatively affecting clinical outcomes.

Bone marrow graft versus peripheral blood graft in haploidentical hematopoietic stem cells transplantation: a retrospective analysis in1344 patients of SFGM-TC registry

The use of peripheral blood (PB) or bone marrow (BM) stem cells graft in haploidentical hematopoietic stem cell transplantation with post-transplant cyclophosphamide (PTCy) for graft-versus-host disease (GVHD) prophylaxis remains controversial. Moreover, the value of adding anti-thymoglobulin (ATG) to PTCy is unknown. A total of 1344 adult patients received an unmanipulated haploidentical transplant at 37 centers from 2012 to 2019 for hematologic malignancy. We compared the outcomes of patients according to the type of graft, using a propensity score analysis. In total population, grade II-IV and III-IV acute GVHD (aGVHD) were lower with BM than with PB. Grade III-IV aGVHD was lower with BM than with PB + ATG. All outcomes were similar in PB and PB + ATG groups. Then, in total population, adding ATG does not benefit the procedure. In acute leukemia, myelodysplastic syndrome and myeloproliferative syndrome (AL-MDS-MPS) subgroup receiving non-myeloablative conditioning, risk of relapse was twice greater with BM than with PB (51 vs. 22%, respectively). Conversely, risk of aGVHD was greater with PB (38% for aGVHD II-IV; 16% for aGVHD III-IV) than with BM (28% for aGVHD II-IV; 8% for aGVHD III-IV). In this subgroup with intensified conditioning regimen, risk of relapse became similar with PB and BM but risk of aGVHD III-IV remained higher with PB than with BM graft (HR = 2.0; range [1.17-3.43], p = 0.012).

Allogeneic hematopoietic stem cell transplantation for adults with therapy-related acute myeloid leukaemia: a retrospective multicentre study on behalf of the SFGM-TC

We report the results from a multicentre retrospective study of 220 adult patients who underwent allogeneic hematopoietic stem cell transplantation (alloHSCT) for therapy-related acute myeloid leukaemia (t-AML). Median age at t-AML diagnosis was 56 years, with a prior history of haematological (45%) or breast (34%). Median time from cytotoxic exposure to t-AML diagnosis was 54.7 months. At transplant, around 20% of patients had measurable residual disease and 3% of patients were not in complete remission. The median follow-up was 21.4 months (Q1-Q3, 5.9-52.8). At 12 months, overall survival (OS), event-free survival (EFS), and graft-versus-host-disease (GVHD)-free-relapse-free survival (GRFS) were 60.7% (95% CI 54.6-67.5), 52.8% (95% CI 46.5-68.4), and 44.1% (95% CI 37.6-51.8), respectively. At 5 years, OS, EFS, and GRFS were 44.1% (95% CI 37.4-52.1), 40.4% (95% CI 33.9-48.1), and 35.3% (95% CI 28.8-43.3), respectively. At last follow-up, 44% of patients were in complete remission (n = 96) and transplant-related mortality accounted for 21% of all deaths (n = 119). Multivariable analysis revealed that uncontrolled t-AML at transplant was associated with lower EFS (HR 1.94, 95% CI 1.0-3.7, p = 0.041). In conclusion, alloHSCT for t-AML shows encouraging results and offers additional opportunity with the emergence of novel pre-graft therapies.

Nonrelapse mortality after CAR T-cell therapy for large B-cell lymphoma: a LYSA study from the DESCAR-T registry

CD19 chimeric antigen receptor (CAR) T cells can induce prolonged remissions and potentially cure a significant proportion of patients with relapsed/refractory large B-cell lymphomas. However, some patients may die of causes unrelated to lymphoma after CAR T-cell therapy. To date, little is known about the nonrelapse mortality (NRM) after CAR T-cell therapy. Using the French DESCAR-T registry, we analyzed the incidence and causes of NRM and identified risk factors of NRM. We report on 957 patients who received standard-of-care axicabtagene ciloleucel (n = 598) or tisagenlecleucel (n = 359) between July 2018 and April 2022, in 27 French centers. With a median follow-up of 12.4 months, overall NRM occurred in 48 patients (5.0% of all patients): early (before day 28 after infusion) in 9 patients (0.9% of all patients and 19% of overall NRM), and late (on/after day 28 after infusion) in 39 patients (4.1% of all patients and 81% of overall NRM). Causes of overall NRM were distributed as follows: 56% infections (29% with non-COVID-19 and 27% with COVID-19), 10% cytokine release syndromes, 6% stroke, 6% cerebral hemorrhage, 6% second malignancies, 4% immune effector cell associated neurotoxicities, and 10% deaths from other causes. We report risk factors of early NRM and overall NRM. In multivariate analysis, both diabetes and elevated ferritin level at lymphodepletion were associated with an increased risk of overall NRM. Our results may help physicians in patient selection and management in order to reduce the NRM after CAR T-cell therapy.

Clinical and immune features of human parvovirus B19 infection in allogeneic stem cell transplantation recipients: A retrospective monocentric study

BACKGROUND

Human parvovirus B19 (B19V) infection is associated with pure red cell aplasia (PRCA) in immunocompromised patients; however, the spectrum of manifestations associated with B19V in allogeneic hematopoietic stem cell transplantation recipients (alloHSCT) has rarely been reported.

METHODS

In this study, we aimed to report clinical and immune features of B19V infection after alloHSCT. We retrospectively collected and analyzed clinical and microbiological data of all transplanted patients with B19V DNAmia or tissue infection detected by polymerase chain reaction (PCR) in our center from 2010 to 2021.

RESULTS

We report 35 cases of B19V infections in 33 patients. Median time from transplant to B19V first PCR positivity was 6.9 months (interquartile range (IQR) [1.6-18.9]). No preferential immune profile, type of transplantation or conditioning was identified. Hematological impairment was the most frequent sign, followed by rash and fever. Unconventional clinical forms were also detected, such as acute myelitis and myositis. For some cases, the direct relationship between symptoms and B19V infection was difficult to prove but was suggested by targeted tissue PCR positivity. When hematological impairment was not at the forefront, reticulocytopenia helped to diagnose B19V infections. Treatment was mainly based on high dose intravenous immunoglobulin.

CONCLUSION

Although hematological impairment was the most frequent sign, B19V can affect multiple targets and lead to atypical manifestations. Because of its heterogeneous clinical presentation, B19V infection is likely under-diagnosed. Diagnosis of unusual B19V organ involvement needs combination of arguments which can include targeted tissue PCR.

Enforced gut homing of murine regulatory T cells reduces early graft-versus-host disease severity

Damage to the gastrointestinal tract following allogeneic hematopoietic stem cell transplantation is a significant contributor to the severity and perpetuation of graft-versus-host disease. In preclinical models and clinical trials, we showed that infusing high numbers of regulatory T cells reduces graft-versus-host disease incidence. Despite no change in in vitro suppressive function, transfer of ex vivo expanded regulatory T cells transduced to overexpress G protein-coupled receptor 15 or C-C motif chemokine receptor 9, specific homing receptors for colon or small intestine, respectively, lessened graft-versus-host disease severity in mice. Increased regulatory T cell frequency and retention within the gastrointestinal tissues of mice that received gut homing T cells correlated with lower inflammation and gut damage early post-transplant, decreased graft-versus-host disease severity, and prolonged survival compared with those receiving control transduced regulatory T cells. These data provide evidence that enforced targeting of ex vivo expanded regulatory T cells to the gastrointestinal tract diminishes gut injury and is associated with decreased graft-versus-host disease severity.

Pooled allogeneic faecal microbiota MaaT013 for steroid-resistant gastrointestinal acute graft-versus-host disease: a single-arm, multicentre phase 2 trial

Background

Failure of gastrointestinal acute graft-versus-host disease (GI-aGvHD) to respond to steroid therapy is associated with limited further therapeutic options. We aimed to assess the safety and efficacy of the first-in-human use of the pooled allogeneic faecal microbiota, MaaT013, for the treatment of steroid-refractory GI-aGvHD.

Methods

This prospective, international, single-arm, phase 2a study reports clinical outcomes from a 24-patient cohort with grade III-IV, steroid refractory GI-aGvHD treated with the pooled allogeneic faecal microbiota MaaT013. MaaT013 involved pooling faecal matter from 3 to 8 screened donors then transplanting the pooled batches into patients to treat GI-aGVHD. The 24 patients were treated in the HERACLES study (Aug 2018 to Nov 2020) at 26 sites in Europe and an additional 52 patients were treated in a compassionate use/expanded access program (EAP) in France (July 2018 to April 2021). The primary endpoint was GI response at day 28, defined as the proportion of patients with GI-aGvHD who had a complete response (CR) or very good partial response (VGPR). GvHD grading and staging were assessed according to the revised Glucksberg criteria. Adverse events and severe adverse events were monitored for 6 months and 12 months, respectively. The HERACLES study was registered with ClinicalTrials.gov (NCT03359980).

Findings

Compared with single donors, MaaT013 is characterised by higher microbial richness and reduced variability across batches. At day 28 (D28), the GI-overall response rate (ORR) was 38% in the prospective population, including 5 complete responses (CR), 2 very good partial responses (VGPR) and 2 partial responses (PR). In the EAP, the GI-ORR was 58% (17 CR, 9 VGPR and 4 PR). The 12-month overall survival (OS) was 25% in the prospective study and 38% in the EAP. Regarding safety, five infectious complications, including 3 sepsis, could not be excluded from being related to the study procedure in HERACLES. Shotgun sequencing analyses of the identified strains suggest that none were found in MaaT013. In the EAP, 18 pharmacovigilance cases were reported among 52 treated patients, including 11 bacteraemia/sepsis. In HERACLES, we observed in stools from responding patients at D28 a higher microbiota richness and increased levels of beneficial bacteria, in particular butyrate producers, along with increased levels of short-chain fatty acid and bile acids. In contrast, stools from non-responding (NR) patients displayed increased levels of pathogenic pro-inflammatory bacteria along with increased systemic inflammatory parameters.

Interpretation

Overall, MaaT013 was safe in this population of highly immunocompromised patients and was associated with responses in some patients with GI-aGvHD and deserves further investigation.

Funding

MaaT Pharma.

Allogeneic transplantation in advanced cutaneous T-cell lymphomas (CUTALLO): a propensity score matched controlled prospective study

BACKGROUND

Advanced-stage cutaneous T-cell lymphomas (CTCLs) are rare, usually refractory, and fatal diseases. Case series have suggested that allogeneic haematopoietic stem cell transplantation (HSCT) might improve the prognosis of advanced-stage CTCLs. The objective of this study was to investigate the effect of allogeneic HSCT compared with non-HSCT therapy on the outcome of individuals with advanced-stage CTCLs.

METHODS

In this prospective, multicentre, matched controlled trial, conducted at 30 hospitals, participants with advanced CTCLs were allocated treatment: if they had an available compatible related donor they were assigned to allogeneic HSCT, or if not they were allocated to non-allogeneic HSCT therapy. Key inclusion criteria were participants aged 18-70 years, with advanced stage mycosis fungoides or Sézary syndrome, and at least one poor prognostic criteria. Participants were excluded if they were not in complete or partial remission of the disease. Propensity score 1:1 matching with replacement (ie, that each participant treated with HSCT was matched to the participant with the closest propensity score treated with non-HSCT therapy, even if they had already been matched) was used to handle confounding factors, with the balance of covariate distribution between HSCT and non-HSCT groups assessed using standardised mean differences. The primary endpoint was progression-free survival in the matched intention-to-treat population. This trial is registered with ClinicalTrials.gov (NCT02520908), and is currently active but not recruiting.

FINDINGS

From June 1, 2016, to March 3, 2022, total of 99 participants were enrolled at 17 centres in France. Participants with a sibling or matched unrelated donor were assigned to allogeneic HSCT (HSCT group, n=55 [56%]) and participants without a donor were assigned to non-allogeneic HSCT treatment (non-HSCT group, n=44 [44%]). The median follow-up among survivors was 12·6 months (IQR 11·0-35·2). In the HSCT group, 51 participants (93%) were 1:1 matched to participants from the non-HSCT group. In the intention-to-treat analysis, median progression-free survival was significantly longer in the HSCT group (9·0 months [95% CI 6·6-30·5]) than in the non-HSCT group (3·0 months [2·0-6·3]), with a hazard ratio of 0·38 (95% CI 0·21-0·69; p<0·0001). In the per-protocol population, 40 participants (78%) in the HSCT group had 101 serious events and 29 participants (67%) in the non-HSCT group had 70 serious adverse events. The most common serious adverse event other than graft-versus-host disease in both groups was infections, occurring in 30 participants (59%) in the HSCT group and in 19 participants (44%) in the non-HSCT group.

INTERPRETATION

Allogeneic HSCT was associated with significantly longer progression-free survival in participants with advanced-stage CTCLs. These results indicate that allogeneic HSCT treatment should be made available to individuals with high-risk, advanced-stage mycosis fungoides or Sézary syndrome who achieve pre-transplant disease remission.

FUNDING

French Ministry of Health, National Cancer Institute, Programme Hospitalier de Recherche Clinique en Cancérologie.

CAR-T Cells and the Kidney: Insights from the WHO Safety Database

BACKGROUND

Chimeric antigen receptor T (CAR-T) cells have proven to be a game changer for treating several hematologic malignancies. Randomized controlled trials have highlighted potential life-threatening adverse drug reactions (ADRs), including cytokine release syndrome (CRS). Acute renal failure (ARF) has also been reported in 20% of the patients treated. However, an analysis of renal safety supported by large-scale real-life data seems warranted.

PATIENTS AND METHODS

We queried VigiBase® for all reports of the Standardised MedDRA Query "acute renal failure" (ARF) involving a CAR-T cell, registered until 24 July 2022. Disproportionality for this ADR was analyzed through calculation of the Information Component [IC (95% confidence interval)]. A positive lower end of the 95% confidence interval of the IC is the threshold used in statistical signal detection in VigiBase®. The same analysis was carried out for various hydroelectrolytic disorders.

RESULTS

We gathered 224 reports of ARF, and 125 reports of hydroelectrolytic disorders involving CAR-T cells. CAR-T cells were disproportionately reported with ARF [IC 1.5 (1.3-1.7)], even after excluding reports mentioning CRS. A significant disproportionate reporting was also found for hypernatremia [IC 3.1 (2.2-3.8)], hyperphosphatemia [IC 3.1 (1.8-3.9)], hypophosphatemia [IC 2.0 (0.6-2.9)], metabolic acidosis [IC 1.8 (1.2-2.2)], hyponatremia [IC 1.6 (1.1-2.0)], and hypercalcemia [IC 1.4 (0.5-2.1)]. There was no disproportionate reporting of dyskalemia.

CONCLUSIONS

This study is limited by the inherent flaws of pharmacovigilance approaches. Nonetheless, our findings suggest that ARF and an array of hydroelectrolytic disorders are potential ADRs of CAR-T cell therapy, in real-life settings and in a nonselected population.

Efficacy of haematopoietic stem cell boost as a rescue for poor graft function after haematopoietic stem cell transplantation: A multicentre retrospective study on behalf of the Francophone Society for Bone Marrow Transplantation and Cell Therapy (SFGM-TC)

Haematopoietic stem cell reinjection may be a curative option for poor graft function after haematopoietic stem cell transplantation; however, literature supporting its use remains limited. We conducted a multicentre retrospective study on behalf of the Francophone Society of Bone Marrow Transplantation and Cellular Therapy, including 55 patients. We demonstrated response rates of nearly 40% and two-year survival of more than 60% in the context of an otherwise deadly complication and we observed that the timing of injection and the degree of cytopenia are strongly associated with outcomes. This study shows the feasibility of the procedure informing on its epidemiology, outcomes and prognostic factors, setting the stage for future guidelines.

Real-life challenges using personalized prognostic scoring systems in acute myeloid leukemia

Personalized medicine is a challenge for patients with acute myeloid leukemia (AML). The identification of several genetic mutations in several AML trials led to the creation of a personalized prognostic scoring algorithm known as the Knowledge Bank (KB). In this study, we assessed the prognostic value of this algorithm on a cohort of 167 real life AML patients. We compared KB predicted outcomes to real-life outcomes. For patients younger than 60-year-old, OS was similar in favorable and intermediate ELN risk category. However, KB algorithm failed to predict OS for younger patients in the adverse ELN risk category and for patients older than 60 years old in the favorable ELN risk category. These discrepancies may be explained by the emergence of several new therapeutic options as well as the improvement of allogeneic stem cell transplantation (aHSCT) outcomes and supportive cares. Personalized medicine is a major challenge and predictions models are powerful tools to predict patient's outcome. However, the addition of new therapeutic options in the field of AML requires a prospective validation of these scoring systems to include recent therapeutic innovations.

Late relapse after hematopoietic stem cell transplantation for acute leukemia: a retrospective study by SFGM-TC

Late relapse (LR) after allogeneic hematopoietic stem cell transplantation (AHSCT) for acute leukemia is a rare event (nearly 4.5%) and raises the questions of prognosis and outcome after salvage therapy. We performed a retrospective multicentric study between January 1, 2010, and December 31, 2016, using data from the French national retrospective register ProMISe provided by the SFGM-TC (French Society for Bone Marrow Transplantation and Cellular Therapy). We included patients presenting with LR, defined as a relapse occurring at least 2 years after AHSCT. We used the Cox model to identify prognosis factors associated with LR. During the study period, a total of 7582 AHSCTs were performed in 29 centers, and 33.8% of patients relapsed. Among them, 319 (12.4%) were considered to have LR, representing an incidence of 4.2% for the entire cohort. The full dataset was available for 290 patients, including 250 (86.2%) with acute myeloid leukemia and 40 (13.8%) with acute lymphoid leukemia. The median interval from AHSCT to LR was 38.2 months (interquartile range [IQR], 29.2 to 49.7 months), and 27.2% of the patients had extramedullary involvement at LR (17.2% exclusively and 10% associated with medullary involvement). One-third of the patients had persistent full donor chimerism at LR. Median overall survival (OS) after LR was 19.9 months (IQR, 5.6 to 46.4 months). The most common salvage therapy was induction regimen (55.5%), with complete remission (CR) obtained in 50.7% of cases. Ninety-four patients (38.5%) underwent a second AHSCT, with a median OS of 20.4 months (IQR, 7.1 to 49.1 months). Nonrelapse mortality after second AHSCT was 18.2%. The Cox model identified the following factors as associated with delay of LR: disease status not in first CR at first HSCT (odds ratio [OR], 1.31; 95% confidence interval [CI], 1.04 to 1.64; P = .02) and the use of post-transplantation cyclophosphamide (OR, 2.23; 95% CI, 1.21 to 4.14; P = .01). Chronic GVHD appeared to be a protective factor (OR, .64; 95% CI, .42 to .96; P = .04). The prognosis of LR is better than in early relapse, with a median OS after LR of 19.9 months. Salvage therapy associated with a second AHSCT improves outcome and is feasible, without creating excess toxicity.

Outcome after allogeneic stem cell transplantation with haploidentical versus HLA-matched donors in patients with higher-risk MDS

Allogeneic hematopoietic stem cell transplantation remains the best curative option for higher-risk myelodysplastic syndrome. The presence of monosomal karyotype and/or complex karyotype abnormalities predicts inferior survival after allo-SCT in MDS patients. Haploidentical allo-SCT has been increasingly used in acute leukemia (AL) and has similar results as using HLA-matched donors, but data on higher-risk MDS is sparse. We compared outcomes in 266 patients with higher-risk MDS after HLA-matched sibling donor (MSD, n = 79), HLA-matched unrelated donor (MUD, n = 139) and HLA haploidentical donor (HID, n = 48) from 2010 to 2019. Median donor age differed between the three groups (p < 0.001). The overall survival was significantly different between the three groups with a better OS observed in the MUD group (p = 0.014). This observation could be explained by a higher progression-free survival with MUD (p = 0.014). The cumulative incidence of grade 2-4 acute GvHD was significantly higher in the HID group (p = 0.051). However, in multivariable analysis, patients transplanted using an HID had comparable mortality to patients transplanted using a MUD (subdistribution hazard ratio [sHR]: 0.58 [0.32-1.07]; p = 0.080) and a MSD ([sHR]: 0.56 [0.28-1.11]; p = 0.094). MUD do not remain a significant positive predictor of survival, suggesting that beyond the donor-recipient HLA matching, the donor age might impact recipient outcome.

Outcomes after allogeneic hematopoietic stem cell transplantation for adults with primary mediastinal B cell lymphoma: a SFGM-TC and LYSA study

Background: Despite therapeutic progress, 10 to 30% of adult patients with primary mediastinal B cell lymphoma (PMBCL) are primary refractory or experience early relapse (R/R). Allogeneic stem cell transplantation (allo-HSCT) thus remains a potentially curative option in this setting.Material and Methods: In this multicenter retrospective study, the outcomes of 33 French and Belgian adult patients allo-transplanted for R/R PMBCL between January 1999 and December 2018, were examined.Results: At allo-HSCT time, patients had received a median of 3 treatment lines, 50% of them were in complete response, 40% in partial response and 10% had a progressive disease. Forty-two percent of the donors were siblings and 39% matched related. The median follow-up for alive patients was 78 months (3.5-157). Considering the whole cohort, 2-year overall survival (OS), progression free survival (PFS) and graft-versus-host disease-free/relapse-free survival (GRFS) were 48% (95%CI: 33-70), 47% (95%CI: 33-68) and 38.5% (95%CI: 25-60) respectively. Cumulative incidence of relapse and non-relapse mortality rates were respectively 34% (95%CI: 18-50) and 18% (95%CI: 7-34). Disease status at transplant was the only factor predicting survivals, patients with progressive disease showing significant lower 2-year PFS (HR: 6.12, 95%CI: 1.32-28.31, p = 0.02) and OS (HR: 7.04, 95%CI: 1.52-32.75, p = 0.013). A plateau was observed for OS and PFS after 4 years with 10 patients alive after this date, suggesting that almost one third of the patients effectively salvaged and undergoing allo-SCT could be cured.Conclusion: This study indicates that allo-HSCT is a valid therapeutic option for R/R PMBCL, providing durable remissions.

Retinoic acid signaling acts as a rheostat to balance Treg function

Regulatory T cells (Tregs) promote immune homeostasis by maintaining self-tolerance and regulating inflammatory responses. Under certain inflammatory conditions, Tregs can lose their lineage stability and function. Previous studies have reported that ex vivo exposure to retinoic acid (RA) enhances Treg function and stability. However, it is unknown how RA receptor signaling in Tregs influences these processes in vivo. Herein, we employed mouse models in which RA signaling is silenced by the expression of the dominant negative receptor (DN) RARα in all T cells. Despite the fact that DNRARα conventional T cells are hypofunctional, Tregs had increased CD25 expression, STAT5 pathway activation, mTORC1 signaling and supersuppressor function. Furthermore, DNRARα Tregs had increased inhibitory molecule expression, amino acid transporter expression, and metabolic fitness and decreased antiapoptotic proteins. Supersuppressor function was observed when wild-type mice were treated with a pharmacologic pan-RAR antagonist. Unexpectedly, Treg-specific expression of DNRARα resulted in distinct phenotypes, such that a single allele of DNRARα in Tregs heightened their suppressive function, and biallelic expression led to loss of suppression and autoimmunity. The loss of Treg function was not cell intrinsic, as Tregs that developed in a noninflammatory milieu in chimeric mice reconstituted with DNRARα and wild-type bone marrow maintained the enhanced suppressive capacity. Fate mapping suggested that maintaining Treg stability in an inflammatory milieu requires RA signaling. Our findings indicate that RA signaling acts as a rheostat to balance Treg function in inflammatory and noninflammatory conditions in a dose-dependent manner.

Allogeneic stem cell transplantation as a curative therapeutic approach for VEXAS syndrome: a case report

TO THE EDITOR

VEXAS (vacuoles, E1 enzyme, X-linked, autoinflammatory, somatic) syndrome is a newly described entity linked to somatic mutation of UBA1, encompassing inflammatory disorders and hematological malignancies. Patients experiments symptoms related to inflammatory manifestations on the skin, joints, lungs. Most patients are refractory to usual anti-inflammatory or immunosuppressive treatments. Half of them will develop hematological diseases, mostly myelodysplastic syndromes. VEXAS patients with hematological malignancies have a poor outcome and no curative option has been described so far. Because in the first reported cohort of VEXAS patients the UBA1 mutation was only found in hematopoietic stem cells but not in fibroblasts, we hypothesized that bone marrow transplantation would provide a cure for the disease. Here we report the case of a VEXAS patient who successfully received an allogeneic hematopoietic stem cell transplantation as a curative option.

Personalized Medicine for TP53 Mutated Myelodysplastic Syndromes and Acute Myeloid Leukemia

Targeting TP53 mutated myelodysplastic syndromes and acute myeloid leukemia remains a significant unmet need. Recently, new drugs have attempted to improve the outcomes of this poor molecular subgroup. The aim of this article is to review all the current knowledge using active agents including hypomethylating agents with venetoclax, eprenetapopt or magrolimab. We include comprehensive analysis of clinical trials to date evaluating these drugs in TP53 myeloid neoplasms as well as discuss future novel combinations for consideration. Additionally, further understanding of the unique clinicopathologic components of TP53 mutant myeloid neoplasms versus wild-type is critical to guide future study. Importantly, the clinical trajectory of patients is uniquely tied with the clonal burden of TP53, which enables serial TP53 variant allele frequency analysis to be a critical early biomarker in investigational studies. Together, significant optimism is now possible for improving outcomes in this patient population.

Targeted gastrointestinal tract homing of regulatory T-cells reduces acute graft-versus-host disease severity by simulating an increase in Treg dose in vivo

Damage to the gastrointestinal (GI) tract following hematopoietic stem cell transplant (HSCT) has been shown to drive the development of acute graft-versus-host disease (aGVHD). We have demonstrated clinically that infusing regulatory T-cells (Treg) during HSCT reduces aGVHD risk while supporting immune recovery; however, high Treg doses were necessary. Here we demonstrate that by promoting Treg homing to the GI tract early post-HSCT, aGVHD severity was reduced. Ex vivo expanded murine Treg were retrovirally transduced to overexpress the orphan chemoattractant receptor GPR15 for colon specific T-cell homing. Despite no change in Treg phenotype or in vitro suppressive function when administered to HSCT recipient mice at the time of transplantation, mice that received GPR15+ Treg exhibited significantly reduced aGVHD severity and prolonged survival compared to control Treg mice (p = 0.0035). To confirm that this resulted from an increased Treg accumulation in the GI tissues, we then assessed the frequency and retention of GPR15+ Treg in mice post-HSCT by in vivo and ex vivo bioluminescent imaging as well as flow analysis. From these data, we observed not only superior localization of GPR15+ Treg within GI tissues, but also significantly reduced inflammation and tissue damage in GPR15+ Treg recipient mice early post-HSCT. Our data provides evidence that deliberate targeting of ex vivo expanded Treg to the GI tract during HSCT significantly reduces injury to the GI tract and reduces aGVHD severity by simulating an increase in Treg dose in vivo. These data provide a rational for the future development of clinical Treg products for increased control of GI aGVHD following HSCT.

Eye amputation following lifitegrast treatment for ocular graft-versus-host disease: First case report

Graft-versus-host disease (GVHD) is a common complication in patients undergoing allogeneic stem cell transplantation for acute myeloblastic leukemia that could be very difficult to treat. Lifitegrast 5% (Xiidra@, Novartis), a new immunosuppressive eye drop, was recently approved by the FDA for the treatment of severe dry eye and is currently under review by the European Medicines Agency. In France, lifitegrast has been approved by the French authorities for temporary use in refractory dry eye syndrome resistant to tear substitutes and topical cyclosporine. To date, serious complications have been reported only exceptionally. In this article, we report the case of a 65-year-old patient with a medical history of acute myeloid leukemia (AML) diagnosed in 2015 who received a first matched related donor transplant. In 2019, this patient developed chronic GVH involving the skin, oral mucosa and eye. Despite taking topical and systemic medications for 3 months, the patient did not report relief of ocular symptoms. Therefore, lifitegrast was prescribed. To our knowledge, we report the first case of corneal perforation in which evisceration was required following treatment with topical lifitegrast for chronic GVH. In the case presented here, it can be assumed that the underlying mechanisms leading to corneal perforation are multifactorial. Using drug accountability criteria, lifitegrast appears to be strongly associated with the development of bacterial keratitis and corneal perforation.

Eprenetapopt Plus Azacitidine in TP53-Mutated Myelodysplastic Syndromes and Acute Myeloid Leukemia: A Phase II Study by the Groupe Francophone des Myélodysplasies (GFM)

TP53-mutated (TP53m) myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML) have very poor outcome irrespective of the treatment received, including 40% responses (20% complete remission [CR]) with azacitidine (AZA) alone, short response duration, and a median overall survival (OS) of approximately 6 months. Eprenetapopt (APR-246), a novel first-in-class drug, leads to p53 protein reconformation and reactivates its proapoptotic and cell-cycle arrest functions.

Underdiagnosed veno-occlusive disease/sinusoidal obstruction syndrome (VOD/SOS) as a major cause of multi-organ failure in acute leukemia transplant patients: an analysis from the EBMT Acute Leukemia Working Party

Allogeneic hematopoietic cell transplantation (alloHCT) is a complex, potentially fatal therapy featuring a myriad of complications. Triggering event(s) of such complications vary significantly, but often a so-called "multi-organ failure" (MOF) is reported as the leading cause of death. The identification of the exact trigger of MOF is critical towards early and disease-specific intervention to improve outcome. We examined data from 202 alloHCT patients reported to have died of MOF from the EBMT registry aiming to determine their exact cause of death focusing on veno-occlusive disease/sinusoidal obstruction syndrome (VOD/SOS) due to its life-threatening, often difficult to capture yet preventable nature. We identified a total of 70 patients (35%) for whom VOD/SOS could be considered as trigger for MOF and leading cause of death, among which 48 (69%) were previously undiagnosed. Multivariate analysis highlighted history of hepatic comorbidity or gentuzumab use and disease status beyond CR1 as the only significant factors predictive of VOD/SOS incidence (OR = 6.6; p = 0.001 and OR = 3.3; p = 0.004 respectively). VOD/SOS-related MOF was widely under-reported, accounting for 27% of deaths attributed to MOF of unknown origin without a previous VOD/SOS diagnosis. Our results suggest most missed cases developed late VOD/SOS beyond 21 days post-alloHCT, highlighting the importance of the newly revised EBMT criteria.

Divergent roles of retinoic acid signaling in T regulatory cell function

Regulatory T cells (Tregs) modulate immune responses to maintain immune homeostasis. Retinoic acid (RA) signaling promotes Treg generation and stability. Paradoxically, we observed that dominant negative RA receptor α expressed only in donor T cells (DNRARαfl/flCD4Cre) dampened inflammation and graft-versus-host disease (GVHD), while increasing Tregs. We found that diminishing RA signaling significantly enhanced their in vitro suppressive capacity. In vivo the adoptive transfer of DNRARαfl/flCD4Cre Tregs at the time of transplant was significantly (p&lt;0.01) more effective than wild type (WT) controls in ameliorating GVHD. Mechanistically, enhanced suppression was associated with elevated expression of suppressive (CTLA-4, GITR, CD39) and fitness (CD25, pSTAT5) markers. To evaluate the intrinsic requirement of RA signaling in Tregs, we generated transgenic mice with conditional DNRARα expression in Tregs (DNRARαfl/fl x Foxp3YFPCre). Surprisingly, the extent of ablation of RA signaling resulted in divergent phenotypes. Heterozygous ablation (DNRARαfl/wt) was permissive of enhanced Treg suppression. In striking contrast and unexpectedly, homozygous ablation (DNRARαfl/fl) impaired Treg suppressive function and caused multi-organ (lung, liver) autoimmunity in &gt;90% of females and males by 3 months of age. Poor suppression is not cell intrinsic as DNRARαfl/fl Tregs isolated from mixed bone marrow chimeras of congenic WT and DNRARαfl/fl x Foxp3YFP Cre had enhanced function. Our studies indicate that RA signaling in Tregs can be targeted to prevent autoimmunity by enhancing Treg suppression or alternatively, promote antitumor responses by reducing Treg function.

Inhibiting fatty acid synthesis (FAS) can prevent and treat chronic graft versus host disease (cGVHD)

GVHD remains the primary complication of allogeneic hematopoietic stem cell transplantation. Considerable interest exists in understanding how metabolism affects immune cell function. We show targeting FAS represents an attractive strategy to ameliorate cGVHD. Acetyl-CoA carboxylase 1 (ACC1) catalyzes the first step of FAS, and can be pharmacologically inhibited with either Soraphen A or 5-(Tetradecyloxy)-2-furoic acid (TOFA). FAS is critical for T cell effector responses, a finding we confirmed using an in vivo multiorgan system cGVHD model with bronchiolitis obliterans, a model dependent on germinal centers (GC), IgG2c secretion, lung deposition and fibrosis. Compared to wild type T cells, cGVHD mice receiving CD4CreACC1fl/fl allogeneic T cells had reduced cGVHD severity assessed by pulmonary function test and immune phenotyping. As thymic regulatory T cell (tTreg) infusion can prevent and treat cGVHD, we examined tTreg FAS needs. Inhibiting FAS in sorted tTreg via drug (Soraphen A; TOFA) or genetic (FoxP3CreACC1fl/fl) strategies increased oxidative and glycolytic metabolism measured by Seahorse assay, that correlated with superior in vitro suppressor function. These findings were extended in vivo where transfer of FoxP3CreACC1fl/fl tTreg, at day 28 following disease establishment, decreased cGVHD severity. Daily treatment of cGVHD mice from day 28 to day 56 with TOFA reversed cGVHD. An in vitro assay in which T follicular regulatory cells suppress T follicular helper and GC B cell class switching showed that inhibiting tTreg FAS can increase their suppression of GC responses. These data provide evidence that inhibiting FAS can prevent or treat cGVHD and enhance Treg function, providing a new approach to ameliorate cGVHD.

Mitochondrial Integrity Regulated by Lipid Metabolism Is a Cell-Intrinsic Checkpoint for Treg Suppressive Function

Regulatory T cells (Tregs) subdue immune responses. Central to Treg activation are changes in lipid metabolism that support their survival and function. Fatty acid binding proteins (FABPs) are a family of lipid chaperones required to facilitate uptake and intracellular lipid trafficking. One family member, FABP5, is expressed in T cells, but its function remains unclear. We show that in Tregs, genetic or pharmacologic inhibition of FABP5 function causes mitochondrial changes underscored by decreased OXPHOS, impaired lipid metabolism, and loss of cristae structure. FABP5 inhibition in Tregs triggers mtDNA release and consequent cGAS-STING-dependent type I IFN signaling, which induces heightened production of the regulatory cytokine IL-10 and promotes Treg suppressive activity. We find evidence of this pathway, along with correlative mitochondrial changes in tumor infiltrating Tregs, which may underlie enhanced immunosuppression in the tumor microenvironment. Together, our data reveal that FABP5 is a gatekeeper of mitochondrial integrity that modulates Treg function.

Dendritic Cell Expression of Retinal Aldehyde Dehydrogenase-2 Controls Graft-versus-Host Disease Lethality

Recent studies have underscored the critical role of retinoic acid (RA) in the development of lineage-committed CD4 and CD8 T cells in vivo. We have shown that under acute graft-versus-host disease (GVHD) inflammatory conditions, RA is upregulated in the intestine and is proinflammatory, as GVHD lethality was attenuated when donor allogeneic T cells selectively expressed a dominant negative RA receptor α that blunted RA signaling. RA can function in an autocrine and paracrine fashion, and as such, the host cell lineage responsible for the production of RA metabolism and the specific RA-metabolizing enzymes that potentiate GVHD severity are unknown. In this study, we demonstrate that enhancing RA degradation in the host and to a lesser extent donor hematopoietic cells by overexpressing the RA-catabolizing enzyme CYP26A1 reduced GVHD. RA production is facilitated by retinaldehyde isoform-2 (RALDH2) preferentially expressed in dendritic cells (DCs). Conditionally deleted RA-synthesizing enzyme RALDH2 in host or to a lesser extent donor DCs reduced GVHD lethality. Improved survival in recipients with RALDH2-deleted DCs was associated with increased T cell death, impaired T effector function, increased regulatory T cell frequency, and augmented coinhibitory molecule expression on donor CD4⁺ T cells. In contrast, retinaldehydrogenase isoform-1 (RALDH1) is dominantly expressed in intestinal epithelial cells. Unexpectedly, conditional host intestinal epithelial cells RALDH1 deletion failed to reduce GVHD. These data demonstrate the critical role of both donor and especially host RALDH2⁺ DCs in driving murine GVHD and suggest RALDH2 inhibition or CYP26A1 induction as novel therapeutic strategies to prevent GVHD.

Rorc restrains the potency of ST2+ regulatory T cells in ameliorating intestinal graft-versus-host disease

Soluble stimulation-2 (ST2) is increased during graft-versus-host disease (GVHD), while Tregs that express ST2 prevent GVHD through unknown mechanisms. Transplantation of Foxp3- T cells and Tregs that were collected and sorted from different Foxp3 reporter mice indicated that in mice that developed GVHD, ST2+ Tregs were thymus derived and predominantly localized to the intestine. ST2-/- Treg transplantation was associated with reduced total intestinal Treg frequency and activation. ST2-/- versus WT intestinal Treg transcriptomes showed decreased Treg functional markers and, reciprocally, increased Rorc expression. Rorc-/- T cells transplantation enhanced the frequency and function of intestinal ST2+ Tregs and reduced GVHD through decreased gut-infiltrating soluble ST2-producing type 1 and increased IL-4/IL-10-producing type 2 T cells. Cotransfer of ST2+ Tregs sorted from Rorc-/- mice with WT CD25-depleted T cells decreased GVHD severity and mortality, increased intestinal ST2+KLRG1+ Tregs, and decreased type 1 T cells after transplantation, indicating an intrinsic mechanism. Ex vivo IL-33-stimulated Tregs (TregIL-33) expressed higher amphiregulin and displayed better immunosuppression, and adoptive transfer prevented GVHD better than control Tregs or TregIL-33 cultured with IL-23/IL-17. Amphiregulin blockade by neutralizing antibody in vivo abolished the protective effect of TregIL-33. Our data show that inverse expression of ST2 and RORγt in intestinal Tregs determines GVHD and that TregIL-33 has potential as a cellular therapy avenue for preventing GVHD.

Cutting Edge: TGF-β and Phosphatidylinositol 3-Kinase Signals Modulate Distinct Metabolism of Regulatory T Cell Subsets

Murine Foxp3⁺ regulatory T cells (Tregs) differentiated in vitro (induced Tregs [iTregs]) in the presence of anti-inflammatory cytokine TGF-β rely predominantly upon lipid oxidation to fuel mitochondrial oxidative phosphorylation. Foxp3 expression underlies this metabolic preference, as it suppresses glycolysis and drives oxidative phosphorylation. In this study, we show that in contrast to iTregs, thymic-derived Tregs (tTregs), engage in glycolysis and glutaminolysis at levels comparable to effector T cells despite maintained Foxp3 expression. Interestingly, exposure of tTregs to the anti-inflammatory cytokine TGF-β represses PI3K-mediated mTOR signaling, inhibits glucose transporter and Hk2 expression, and reprograms their metabolism to favor oxidative phosphorylation. Conversely, replicating the effects of inflammation via elevation of PI3K signaling has minimal effects on tTregs but dramatically enhances the glycolysis of normally oxidative iTregs, resulting in reduction of Foxp3 expression. Collectively, these findings suggest both extrinsic and intrinsic factors govern the unique metabolic signature of Treg subsets.

The vimentin intermediate filament network restrains regulatory T cell suppression of graft-versus-host disease

Regulatory T cells (Tregs) are critical for maintaining immune homeostasis. However, current Treg immunotherapies do not optimally treat inflammatory diseases in patients. Understanding the cellular processes that control Treg function may allow for the augmentation of therapeutic efficacy. In contrast to activated conventional T cells, in which protein kinase C-θ (PKC-θ) localizes to the contact point between T cells and antigen-presenting cells, in human and mouse Tregs, PKC-θ localizes to the opposite end of the cell in the distal pole complex (DPC). Here, using a phosphoproteomic screen, we identified the intermediate filament vimentin as a PKC-θ phospho target and show that vimentin forms a DPC superstructure on which PKC-θ accumulates. Treatment of mouse Tregs with either a clinically relevant PKC-θ inhibitor or vimentin siRNA disrupted vimentin and enhanced Treg metabolic and suppressive activity. Moreover, vimentin-disrupted mouse Tregs were significantly better than controls at suppressing alloreactive T cell priming in graft-versus-host disease (GVHD) and GVHD lethality, using a complete MHC-mismatch mouse model of acute GVHD (C57BL/6 donor into BALB/c host). Interestingly, vimentin disruption augmented the suppressor function of PKC-θ-deficient mouse Tregs. This suggests that enhanced Treg activity after PKC-θ inhibition is secondary to effects on vimentin, not just PKC-θ kinase activity inhibition. Our data demonstrate that vimentin is a key metabolic and functional controller of Treg activity and provide proof of principle that disruption of vimentin is a feasible, translationally relevant method to enhance Treg potency.

Human CD19-Targeted Mouse T Cells Induce B Cell Aplasia and Toxicity in Human CD19 Transgenic Mice

The clinical success of chimeric antigen receptor (CAR) T cell therapy for CD19+ B cell malignancies can be limited by acute toxicities and immunoglobulin replacement needs due to B cell aplasia from persistent CAR T cells. Life-threatening complications include cytokine release syndrome and neurologic adverse events, the exact etiologies of which are unclear. To elucidate the underlying toxicity mechanisms and test potentially safer CAR T cells, we developed a mouse model in which human CD19 (hCD19)-specific mouse CAR T cells were adoptively transferred into mice whose normal B cells express a hCD19 transgene at hemizygous levels. Compared to homozygous hCD19 transgenic mice that have ∼75% fewer circulating B cells, hemizygous mice had hCD19 frequencies and antigen density more closely simulating human B cells. Hemizygous mice given a lethal dose of hCD19 transgene-expressing lymphoma cells and treated with CAR T cells had undetectable tumor levels. Recipients experienced B cell aplasia and antigen- and dose-dependent acute toxicities mirroring patient complications. Interleukin-6 (IL-6), interferon γ (IFN-γ), and inflammatory pathway transcripts were enriched in affected tissues. As in patients, antibody-mediated neutralization of IL-6 (and IFN-γ) blunted toxicity. Apparent behavioral abnormalities associated with decreased microglial cells point to CAR-T-cell-induced neurotoxicity. This model will prove useful in testing strategies designed to improve hCD19-specific CAR T cell safety.

Effects of MicroRNA on Regulatory T Cells and Implications for Adoptive Cellular Therapy to Ameliorate Graft-versus-Host Disease

Regulatory T cells (Tregs) are key mediators of the immune system. MicroRNAs (miRNAs) are a family of ~22 nucleotide non-coding RNAs that are processed from longer precursors by the RNases Drosha and Dicer. miRNA regulates protein expression posttranscriptionally through mRNA destabilization or translational silencing. A critical role for miRNA in Treg function was initially discovered when both Dicer and Drosha knockout (KO) mice were found to develop a fatal autoimmune disease phenotypically similar to Foxp3 KO mice.

Immune stimulation during chemotherapy increases incidence of acute graft versus host disease in acute myeloid leukemia: A study on behalf of SFGM-TC and ALFA

60-70% of AML patients have an indication of allogeneic hematopoietic stem cell transplantation (allo-HSCT) during their treatment. Graft versus host disease (GvHD), the major cause of mortality and comorbidities post-transplantation, develops by immunological mechanism and decides greatly prognosis and quality of life (QoL) of graft recipient. Current GvHD prophylaxis is not personalized. Infections, toxicities and leukemic infiltration complicate the first chemotherapy phases prior to allo-HSCT. They, to certain extent, induce local immune stimulation. Impact of immune stimulation of this period on incidence of GvHD has not been evaluated. We retrospectively studied 238 AML patients transplanted at first remission from 21 French centers in the ALFA-0702 protocol and found that cutaneous and digestive immune stimulation during induction increases the incidence of skin and gut aGVHD, respectively. Furthermore, prolonged febrile duration correlates with elevated incidence of grade II-IV aGvHD. Thus, we identified a group of patients with higher risk of aGvHD. The benefit of personalized GvHD prophylaxis should be explored in a prospective cohort to decrease incidence of aGvHD in these patients and improve their QoLs.

Impact of eculizumab treatment on paroxysmal nocturnal hemoglobinuria: a treatment versus no-treatment study

Intravascular hemolysis in Paroxysmal nocturnal hemoglobinuria (PNH) can effectively be controlled with eculizumab, a humanized monoclonal antibody that binds complement protein C5. We report here a retrospective comparison study between 123 patients treated with eculizumab in the recent period (>2005) and 191 historical controls (from the French registry). Overall survival (OS) at 6 years was 92% (95%CI, 87 to 98) in the eculizumab cohort versus 80% (95%CI 70 to 91) in historical controls diagnosed after 1985 (HR 0.38 [0.15 to 0.94], P = 0.037). There were significantly fewer thrombotic events (TEs) in the group of patients treated with eculizumab (4% [1-10]) as compared to the historical cohort (27% [20-34]). However, we found that TEs may still occur after the initiation of eculizumab treatment and that previous TEs still have a negative impact on survival. Evolutions to myelodysplastic syndrome or acute leukemia were similar in both cohorts. There was less evolution to aplastic anemia in the treatment group. In multivariate analysis, absence of a previous TE and treatment with eculizumab were associated with a better OS. Treatment with eculizumab improves overall survival in classic PNH patients without increasing the risk of clonal evolution.

Invasive aspergillosis in neutropenic patients during hospital renovation: effectiveness of mechanical preventive measures in a prospective cohort of 438 patients

BACKGROUND

Aspergillus species are the main cause of invasive fungal disease for patients with severe and prolonged neutropenia. Building or renovation works have been shown as one of the major causes of outbreaks of aspergillosis.

OBJECTIVES

This study aimed to assess the effectiveness of introduction and adaptation by air sampling of mechanical preventive measures on the incidence of invasive pulmonary aspergillosis in neutropenic patients during hospital renovation.

PATIENTS

All of the patients admitted for prolonged and severe neutropenia during a renovation period from 2003 to 2008 were prospectively enrolled. Invasive pulmonary aspergillosis (IPA) cases were classified as possible, probable, and proven, according to the 2008 European Organization for Research and Treatment of Cancer/Invasive Fungal Infections Cooperative Group and the National Institute of Allergy and Infectious Diseases Mycoses Study Group (EORTC/MSG) Consensus Group criteria. The effectiveness of preventive measures was determined by air sampling.

RESULTS

We recorded 705 hospitalizations for neutropenia concerning 438 patients. The majority of hospitalized neutropenic patients was treated for acute leukemia (38.3 %), followed by patients suffering from non-Hodgkin and Hodgkin lymphomas (33 %). The total cumulative incidence of probable and proven IPA was 4.1 %. Risk factors for developing IPA were underlying disease, treatment course at the time of hospitalization, and the mean duration of hospitalization and of neutropenia.

CONCLUSIONS

In this prospective study, the incidence of invasive pulmonary aspergillosis did not increase in neutropenic patients during a renovation period because of efficient mechanical preventive measures systematically adjusted using the results of air sampling.