Unconventional T Cells Influence Clinical Outcome After Allogeneic Hematopoietic Cell Transplantation.

We evaluated the impact of early recovery of mucosal-associated invariant T cells (MAIT) and gamma-delta (γδ) T cells, especially Vδ2+ T cells, on the clinical outcomes of 76 patients who underwent allogeneic hematopoietic cell transplantation (allo-HCT). MAIT cells were identified at day 20-30 post-transplant using flow cytometry and defined as CD3+ TCRVα7.2+CD161+. Two subsets of Vδ2+ T cells were analyzed according to the expression of CD26. The cytotoxicity profile of MAIT and Vδ2+ T cells was analyzed according to the intracellular expression of perforin and granzyme B, and intracellular IFN-γ was evaluated after in vitro activation. CD26+Vδ2+ T cells displayed higher intracellular levels of IFN-γ, whereas CD26- Vδ2+ T were found to be more cytotoxic. Moreover, MAIT cell frequency was correlated with the frequency of Vδ2+ T cells with a better correlation observed with Vδ2+CD26+ than with the Vδ2+CD26- T cell subset. By using the composite endpoint graft-versus-host disease (GvHD)-free, relapse-free survival (GRFS) as the primary endpoint, we found that patients with a higher MAIT cell frequency at day 20-30 after allo-HCT had a significantly increased GRFS and a better overall survival (OS) and disease-free survival (DFS). Moreover, patients with a low CD69 expression by MAIT cells had an increased cumulative incidence of grade 2-4 acute GvHD (aGvHD). These results suggest that MAIT cell reconstitution may provide mitigating effects early after allo-HCT depending on their activation markers and functional status. Patients with a high frequency of Vδ2+CD26+ T cells had a significantly higher GRFS, OS and DFS, but there was no impact on cumulative incidence of grade 2-4 aGVHD, non-relapse mortality and relapse. These results revealed that the impact of Vδ2+ T cells on the success of allo-HCT may vary according to the frequency of the CD26+ subset.

Extracorporeal photopheresis as first-line strategy in the treatment of acute graft-versus-host disease after hematopoietic stem cell transplantation: A single-center experience.

BACKGROUND AIMS: Corticosteroids are the standard first-line treatment for acute graft-versus-host disease (aGVHD), but they are associated with many complications, and less than half of patients have a sustained response. METHODS: To improve outcomes, we performed a retrospective study to analyze the efficacy of the addition of extracorporeal photopheresis (ECP) to low-dose corticosteroids in 37 adult patients (median age, 57 years) with skin-predominant aGVHD (grade I, n = 17; grade II, n = 18; and grade III, n = 2). All patients received ECP in combination with 1 mg/kg prednisone (n = 26) or topical steroids (n = 11). RESULTS: Overall response rate was 81% after a median of three ECP procedures (range, 2-8), including 22 complete responses (CR, 59%) and eight very good partial responses (VGPR, 22%). The 11 patients treated with topical corticosteroids achieved CR. Furthermore, 16 (62%) patients reached prednisone withdrawal at a median of 100 days (range, 42-174 days) after its initiation. Eighteen patients developed chronic GVHD (cGVHD); 11 of them (who were in CR of aGVHD) had a new-onset cGVHD, and seven experienced progressive cGVHD (five non-responding and two VGPR patients). A second-line immunosuppressive treatment was initiated in only five (14%) non-responding patients. With a median follow-up of 31 months (range, 6-57 months) 2-year overall survival and non-relapse mortality were 74% and 11%, respectively. CONCLUSIONS: Overall, the combination of low-dose corticosteroids and ECP appear to be safe and effective for first-line treatment of skin predominant aGVHD.

Thiotepa, Busulfan, and Fludarabine Conditioning Regimen in T Cell-Replete HLA-Haploidentical Hematopoietic Stem Cell Transplantation.

We report the outcomes of 51 patients who underwent unmanipulated haploidentical hematopoietic stem cell transplantation (haplo-HSCT) with post-transplantation cyclophosphamide (PT-Cy) and antithymocyte globulin (ATG), from peripheral blood stem cells (PBSCs) or bone marrow, after receipt of a TBF (thiotepa, busulfan, and fludarabine) conditioning regimen. Their median age was 55 years (range, 16 to 72 years). Hematologic diagnoses included acute leukemias (n = 31), lymphoid neoplasm (n = 12), myeloproliferative neoplasm (n = 5), and myelodysplastic syndromes (n = 3). Thirty-seven patients (73%) were in complete remission. Graft-versus-host disease (GVHD) prophylaxis consisted of cyclosporine and mycophenolate for all patients, associated with ATG in 39 patients (76.5%). The median time to neutrophil engraftment was 17 days (range, 12 to 34 days). The cumulative incidences of grade II-IV and grade III-IV acute GVHD were 27.5% and 14%, respectively. In patients receiving a PBSC graft and ATG prophylaxis, grade II-IV aGVHD occurred in 16% of patients. The use of ATG and a lower thiotepa dose (5 mg/kg versus 10 mg/kg) were associated with a reduced cumulative incidence of grade II-IV acute GVHD (P = .03 and .005, respectively). The 2-year cumulative incidence of chronic GVHD was 29% and was significantly reduced to 13% with the lower thiotepa dose (P = .002). After a median follow-up of 25 months (range, 12 to 62 months), the cumulative incidences of nonrelapse mortality, relapse, overall survival (OS), disease-free survival (DFS), and GVHD-free, relapse-free survival (GFRFS) were 20%, 22.5%, 67%, 58%, and 51%, respectively. Pretransplantation disease status (complete remission versus others) was the main factor associated with OS, DFS, and GFRFS. In conclusion, the TBF conditioning regimen is an appealing platform in the haplo-HSCT setting with PT-Cy in terms of engraftment rate, toxicity, and disease control. We found no benefit of a thiotepa dose of 10 mg/kg compared with a dose of 5 mg/kg. ATG reduced the risk of acute GVHD without comprising outcomes.

Impact of cyclosporine A concentration on acute graft-vs-host disease incidence after haploidentical hematopoietic cell transplantation.

OBJECTIVES: This retrospective study analyzed the impact of early cyclosporine A (CsA) initiation (day -3) on the risk of acute graft-vs-host disease (aGvHD) after haploidentical hematopoietic cell transplantation (Haplo-HCT) using post-transplant cyclophosphamide. METHODS: Sixty-one consecutives patients who underwent Haplo-HCT were analyzed. RESULTS: At day +180, the cumulative incidences of grade II-IV and grade III-IV aGvHD were 39% and 18%, respectively. Patients having a lowest CsA concentration (<301 ng/mL; the cutoff value used to segregate the patients between low and high CsA concentrations) in the first week after Haplo-HCT had a significantly higher risk of grade II-IV aGvHD (P = 0.02), severe grade III-IV aGvHD (P = 0.03), cGvHD (P = 0.02), and extensive cGvHD (P = 0.04). In multivariate analysis, a higher CsA concentration (≥301 ng/mL) during the first week following Haplo-HCT was the only parameter significantly associated with a reduced risk of grade II-IV and grade III-IV aGvHD (RR = 0.21; P = 0.049 and RR < 0.001; P < 0.0001, respectively). We find no correlation between CsA concentration and relapse, non-relapse mortality, progression-free survival, GvHD-free and progression-free survival, or overall survival. CONCLUSIONS: CsA could be initiated early before Haplo-HCT with achievement of high CsA concentration to reduce the risk of aGvHD without any detrimental effect on relapse.

Human herpesvirus type 6 reactivation after haploidentical hematopoietic cell transplantation with post-transplant cyclophosphamide and antithymocyte globulin: risk factors and clinical impact.

Human herpesvirus type 6 (HHV6) reactivation after haploidentical hematopoietic cell transplantation (HCT) with post-transplant cyclophosphamide (PT-Cy) has been scarcely studied, especially when antithymocyte globulin (ATG) is added to the graft-versus-host disease (GvHD) prophylaxis. We conducted a retrospective cohort study in 100 consecutive patients receiving haploidentical HCT with PT-Cy. We systematically monitored HHV6 DNA loads in blood samples on a weekly basis using quantitative PCR until day +100. The 100-day cumulative incidence of HHV6 reactivation was 54%. Clinically significant HHV6 infections were rare (7%), associated with higher HHV6 DNA loads, and had favorable outcomes after antiviral therapy. The main risk factor for HHV6 reactivation was a low absolute lymphocyte count (ALC) \< 290/µL on day +30 (68% versus 40%, p = 0.003). Adding ATG to PT-Cy did not increase the incidence of HHV6 reactivation (52% with ATG versus 79% without ATG, p = 0.12). Patients experiencing HHV6 reactivation demonstrated delayed platelet recovery (HR 1.81, 95% CI 1.07-3.05, p = 0.026), higher risk of acute grade II-IV GvHD (39% versus 9%, p \< 0.001) but similar overall survival and non-relapse mortality to the other patients. In conclusion, our findings endorse the safety of combining ATG and PT-Cy in terms of the risk of HHV6 reactivation and infection in patients undergoing haploidentical HCT. Patients with a low ALC on day +30 face a higher risk of HHV6 reactivation and may require careful monitoring.

Reduced post-transplant cyclophosphamide dose with antithymocyte globulin in peripheral blood stem cell haploidentical transplantation.

Post-transplant cyclophosphamide (PT-Cy) is effective for graft-versus-host disease (GVHD) prophylaxis, but it may cause dose-dependent toxicities, particularly in frail patients. Therefore, we compared the outcomes with a reduced PT-Cy total dose (70 mg/kg) to those with the standard PT-Cy dose (100 mg/kg) in haploidentical hematopoietic cell transplantation (HCT) patients aged ≥ 65 years and those with cardiac comorbidities. All consecutive patients with a hematological malignancy receiving peripheral blood stem cells (PBSCs) after a thiotepa-based conditioning with low-dose antithymocyte globulin were included. Thirty-three patients received PT-Cy at 70 mg/kg and 25 at 100 mg/kg. PT-Cy dose reduction did not increase the risk of GVHD and was associated with faster neutrophil and platelet recovery, and lower cumulative incidences of bacteremia (38% versus 72%, p = 0.004) and cardiac complications (12% versus 44%, p = 0.028). At 2 years, GVHD-free, relapse-free survival (GRFS) was higher with the reduced dose compared to the standard dose (60% versus 33%, p = 0.04). In conclusion, reducing PT-Cy total dose to 70 mg/kg is a safe and valid approach for elderly patients and those with cardiac comorbidities underdoing haploidentical HCT with PBSCs and low-dose antithymocyte globulin. The reduced PT-Cy dose was associated with improved hematological count recovery, lower incidence of toxicities, and higher GRFS.

Thiotepa, busulfan and fludarabine conditioning-regimen is a promising approach for older adult patients with acute lymphoblastic leukemia treated with allogeneic stem cell transplantation.

For acute lymphoblastic leukemia (ALL) patients, total body irradiation (TBI)- based conditioning regimens are the first choice specially in young population. However, several studies have shown an equivalence in clinical outcomes with thiotepa-based conditioning regimen. We performed a retrospective study to evaluate the outcome of adult ALL patients who received allogeneic hematopoietic stem cell transplantation (allo-HCT) with a thiotepa-busulfan-fludarabine (TBF) myeloablative conditioning regimen with reduced toxicity. Fifty-five patients received a TBF regimen. The median age of the patients was 51 years (range, 17 to 72.4). Most patients had a diagnosis of B-ALL (93%) with 7% having T-ALL. Two - and 5-year overall survival was 73.2% and 64%, respectively. At 2 years, leukemia-free survival and GVHD-free, relapse-free survival were 59.5% and 57.6%, and at 5 years, 53.4% and 51.8%, respectively. The 5-year non-relapse mortality was 15%. The day 180 cumulative incidence (CI) of grade II-IV acute GVHD and grade III-IV acute GVHD were 38.2% and 5.5%, respectively. At 2 years, the CI of chronic GVHD and extensive chronic GVHD was 16.9% and 1.9%, respectively. Our study results do suggest that using TBF as the conditioning regimen in adult ALL patients is a promising option with acceptable toxicity.

Stable pulmonary function after haploidentical stem cell transplantation with post-transplant cyclophosphamide: a single center experience.

Prior studies have reported pulmonary function tests (PFT) before and after related and unrelated allogeneic hematopoietic stem cell transplantation (HSCT). However, limited data exist on the evaluation of lung function after haploidentical stem cell transplantation (HAPLO) with post-transplant cyclophosphamide (PTCY). We retrospectively reported the evaluation of PFTs at screening before HAPLO in 80 patients at 100 days and 1 year of follow-up. The proportion of surviving patients with available PFTs at 100 days and 1 year were 86% and 68%, respectively. During the follow-up period, four patients met the criteria for bronchiolitis obliterans syndrome and two for interstitial lung disease. Overall survival was 73% (95% CI 62-82%) at 2 years. We observed a significant reduction in diffusing capacity of the lungs for carbon monoxide (DLCO) corrected for the most recent hemoglobin concentration (DLCOc) at 100 days after HAPLO. However, an overall substantial stable pulmonary function was observed at 1 year.

Impact of gut fungal and bacterial communities on the outcome of allogeneic hematopoietic cell transplantation.

Patients receiving allogeneic hematopoietic cell transplantation (alloHCT) were previously shown to display a bacterial gut dysbiosis; however, limited data are available regarding the role of fungal microbiota in these patients. We evaluated the bacterial and fungal composition of the fecal microbiota at day 0 of alloHCT. Higher bacterial diversity was associated with an improved overall survival (OS) and disease-free survival (DFS). While fungal diversity had no impact on patient outcomes, we observed that high versus low relative abundance of Candida albicans in alloHCT patients at day 0 was associated with a significantly lower OS, DFS and graft-versus-host-free, relapse-free survival (GRFS) (p = 0.0008, p = 0.0064 and p = 0.026, respectively). While these results are limited by low patient numbers and low fungal read counts in some samples, they suggest a potentially important role for C albicans in alloHCT.

Thiotepa-busulfan-fludarabine as a conditioning regimen for patients with myelofibrosis undergoing allogeneic hematopoietic transplantation: a single center experience.

We assessed the outcomes associated with thiotepa, busulfan and fludarabine (TBF) conditioning regimen in a cohort of 29 consecutive patients allografted for myelofibrosis (MF). The median age was 56 (range 42-70) years. According to the refined Dynamic International Prognostic Scoring System (DIPSS-plus), 15 (52%) patients were classified as high risk. Graft source was peripheral blood stem cells in 27 patients. Donor type was HLA-matched related (n = 5), matched unrelated (n = 16), mismatched unrelated (n = 1), and haploidentical (n = 7). All but 2 patients engrafted. The cumulative incidence (CI) of grade II-IV acute graft-versus-host disease (GVHD) was 21% (95% CI, 10-42) at day 100. The CI of chronic GVHD was 39% (95% CI, 23-65) at 3 years. The median follow-up period was 39 (range 14-60) months. Overall survival was 69% (95% CI, 50-83) at 3 years. No relapse was observed. TBF is a valid conditioning strategy in patients with MF.

Early Cardiac Toxicity Associated With Post-Transplant Cyclophosphamide in Allogeneic Stem Cell Transplantation.

BACKGROUND: Post-transplant cyclophosphamide (PT-Cy) has become a standard of care in haploidentical hematopoietic stem cell transplantation (HSCT) to reduce the risk of graft-versus-host disease. However, data on cardiac events associated with PT-Cy are scarce. OBJECTIVES: This study sought to assess the incidence and clinical features of cardiac events associated with PT-Cy. METHODS: The study compared clinical outcomes between patients who received PT-Cy (n = 136) and patients who did not (n = 195), with a focus on early cardiac events (ECE) occurring within the first 100 days after HSCT. All patients had the same systematic cardiac monitoring. RESULTS: The cumulative incidence of ECE was 19% in the PT-Cy group and 6% in the no-PT-Cy group (p < 0.001). The main ECE occurring after PT-Cy were left ventricular systolic dysfunction (13%), acute pulmonary edema (7%), pericarditis (4%), arrhythmia (3%), and acute coronary syndrome (2%). Cardiovascular risk factors were not associated with ECE. In multivariable analysis, the use of PT-Cy was associated with ECE (hazard ratio: 2.7; 95% confidence interval: 1.4 to 4.9; p = 0.002]. Older age, sequential conditioning regimen, and Cy exposure before HSCT were also associated with a higher incidence of ECE. Finally, a history of cardiac events before HSCT and ECE had a detrimental impact on overall survival. CONCLUSIONS: PT-Cy is associated with a higher incidence of ECE occurring within the first 100 days after HSCT. Patients who have a cardiac event after HSCT have lower overall survival. These results may help to improve the selection of patients who are eligible to undergo HSCT with PT-Cy, especially older adult patients and patients with previous exposure to Cy.

High-dose post-transplant cyclophosphamide impairs γδ T-cell reconstitution after haploidentical haematopoietic stem cell transplantation using low-dose antithymocyte globulin and peripheral blood stem cell graft.

OBJECTIVES: Haploidentical haematopoietic cell transplantation (Haplo-HCT) using peripheral blood stem cell (PBSC) grafts and post-transplant cyclophosphamide (PTCy) is being increasingly used; however, data on immunological reconstitution (IR) are still scarce. METHODS: This retrospective study evaluated T-cell immunological reconstitution in 106 adult patients who underwent allogeneic haematopoietic cell transplantation for haematologic malignancies between 2013 and 2016. RESULTS: At D30, while conventional T cells reached similar median counts in Haplo-HCT recipients (n = 19) and controls (n = 87), γδ and Vδ2+ T-cell median counts were significantly lower in Haplo-HCT recipients and it persists at least until D360 for Vδ2+ T cells. PTCy induces a significant reduction in early γδ and Vδ2+ T-cell proliferation at D  7. At one year, the rate of increase in Epstein-Barr virus (EBV) viral load was significantly higher in Haplo-HCT recipients as compared to controls (61% versus 34%, P = 0.02). In multivariate analysis, a higher γδ T-cell count (> 4.63 µL-1) at D30 was the only independent parameter significantly associated with a reduced risk of increase in EBV viral load (RR 0.34; 95% CI, 0.15-0.76, P = 0.009). CONCLUSION: Immunological reconstitution of γδ T cells is significantly delayed after Haplo-HCT using PTCy and low-dose ATG and is associated with an increased risk of increase in EBV viral load.

Thiotepa and antithymocyte globulin-based conditioning prior to haploidentical transplantation with posttransplant cyclophosphamide in high-risk hematological malignancies.

We report results of a thiotepa-based conditioning in haploidentical stem cell transplantation (haplo-SCT) with posttransplant cyclophosphamide (PT-CY) and antithymocyte globulin (ATG), for unmanipulated peripheral blood stem cell (PBSC) transplants, in 80 patients with hematological malignancies. Patients in complete remission (CR) received a thiotepa-busulfan-fludarabine (TBF) regimen, while patients with relapsed/refractory (R/R) malignancies received a sequential regimen consisting of thiotepa-etoposide-cyclophosphamide (TEC) and reduced-intensity conditioning (RIC). The median age was 52 (range, 17-72) years, 44% patients had R/R disease at transplant, and the median follow-up was 417 (range, 180-1595) days. The median days to neutrophil engraftment was 17 (range, 12-34). The cumulative incidences (CI) of acute graft-versus-host disease (GVHD) grade III to IV, severe chronic GVHD, nonrelapse mortality (NRM), and relapse were 16%, 16%, 26, and 26%, respectively. The 2-year overall survival (OS) and disease-free survival (DFS) were 53% and 47%, respectively. There were no significant differences between the patients in CR and R/R patients in terms of engraftment, GVHD, NRM, relapse, OS, or DFS. We conclude that thiotepa-based regimen with PT-CY can be modified with PBSC and ATG, still providing low toxicity, protection against GVHD, and low relapse incidence. Particularly encouraging are the results with the modification to sequential regimen in R/R patients.

Tolerability and Efficacy of Treatment With Azacytidine as Prophylactic or Preemptive Therapy for Myeloid Neoplasms After Allogeneic Stem Cell Transplantation.

INTRODUCTION/BACKGROUND: Azacytidine (AZA) has been used as a promising treatment for relapse after allogeneic transplantation. A clear benefit has been demonstrated when treating patients with a reduced disease burden, thus a prophylactic and preemptive approach to these patients has emerged. MATERIALS AND METHODS: We retrospectively analyzed patients with myeloid malignancies treated with azacytidine in the posttransplantation setting between September 2013 and April 2018 in a single tertiary care hospital. Of 32 patients analyzed, 21 were treated for prophylactic use and 11 preemptively, with a median follow-up of 20 months. Prophylactic treatment consisted of AZA at 32 mg/m2 for 5 days every 28 days, and preemptive treatment of AZA 75 mg/m2 for 5 or 7 days per cycle. In addition, 10 patients received one or more donor lymphocyte infusions (DLIs). Two patients presented with infectious complications demanding hospitalization, and 13 patients (10 in the prophylactic group and 3 in the preemptive group) presented graft-versus-host disease (GvHD). Of patients who had GvHD, 3 needed treatment discontinuation. Overall, 12 patients suspended treatment, 8 for disease progression and 1 due to patient request. RESULTS: In the prophylactic group, all patients are alive at 1 year with an event-free survival (EFS) of 95%, as only 1 patient relapsed. In the preemptive group, 1-year EFS was 54% and 1-year overall survival was 82%. CONCLUSION: Low-dose AZA in posttransplantation patients with myeloid neoplasms is a well-tolerated therapy with the potential to prevent relapse and maintain stable remissions. Randomized prospective trials are needed to determine patient selection and dosage, timing, and duration of treatment.