Anti-PD-1 combined with hypomethylating agent and CAG regimen bridging to allogeneic hematopoietic stem cell transplantation: a novel strategy for relapsed/refractory acute myeloid leukemia.

Introduction: The prognosis of relapsed/refractory acute myeloid leukemia (r/rAML) is dismal, and allogeneic hematopoietic stem cell transplant (allo-HSCT) is a potential cure. Combining anti-PD-1, hypomethylating agent (HMA), and CAG (cytarabine, aclarubicin/idarubicin, granulocyte colony-stimulating factor) regimen has showed primary efficacy in r/rAML. However, pre-transplant exposure to anti-PD-1 may lead to severe graft-versus-host disease (GVHD). This preliminary study aimed to evaluate the safety and efficacy of allo-HSCT in r/rAML patients receiving the anti-PD-1+HMA+CAG regimen. Methods: Fifteen r/rAML patients (12 related haploidentical donors [HIDs], 2 matched siblings, 1 unrelated donor) received this regimen and subsequent peripheral blood HSCT. Results: Four patients with HIDs received a GVHD prophylaxis regimen consisted of Anti-thymocyte globulin and a reduced-dose of post-transplant cyclophosphamide. The median follow-up was 20.9 months (range, 1.2-34.2). The cumulative incidences of acute GVHD grade 2-4 and grade 3-4 were 40% and 13.3%, respectively. The 2-year incidence of moderate-to-severe chronic GVHD, non-relapse mortality, and relapse were 10%, 22.3%, and 22.5%, respectively. The 2-year overall survival and GVHD-free/relapse-free survival rates were 54% and 48.6%, respectively. No death or relapse was observed in the PTCy group. Conclusion: The anti-PD-1+HMA+CAG regimen bridging to allo-HSCT for r/r AML was tolerable with promising efficacy. GVHD prophylaxis with PTCy for HID-HSCT showed preliminary survival advantage.

Recent advances in acute gastrointestinal graft versus host disease (aGvHD): aspects of steroid-resistant disease.

Acute Graft versus Host Disease (aGvHD) is a common immunological complication occurring in patients undergoing allogeneic hematopoietic stem cell transplantation (allo-HSCT). Moreover, aGvHD is associated with a higher risk of infections and metabolic complications, affecting non-relapse mortality. Progress in transplantation has changed the prophylactic and therapeutic strategies of aGvHD and improved patient outcomes. The standard first-line therapy remains steroids, with a response rate of about 50%. The Janus Kinase 2 (JAK2) inhibitor, ruxolitinib, is an effective second-line therapy. The management of patients who developed a disease that is refractory to steroids and ruxolitinib, especially in the severe gastrointestinal forms of aGvHD, is not validated and remains an unmet medical need. In the article, we present the current clinical practice, as well as the latest advances targeting pathophysiological pathways of GvHD and gut microbiota, which may be a potential future of aGvHD therapy.

Human placental mesenchymal stromal cells alleviate intestinal oxidative damage in mice with graft-versus-host disease via CD73/adenosine/PI3K/Akt/GSK-3ß axis.

BACKGROUND: Intestinal damage is a common and serious complication in patients with graft-versus-host disease (GVHD). Human placental mesenchymal stromal cells (hPMSCs) ameliorate GVHD tissue damage by exerting anti-oxidative effects; however, the underlying mechanisms remain not fully clear. METHODS: A GVHD mouse model and tumor necrosis factor-α (TNF-α)-stimulated human colon epithelial cell lines NCM460 and HT-29 cells were used to investigate the mechanisms of hPMSCs alleviating GVHD-induced intestinal oxidative damage. RESULTS: hPMSCs reduced TNF-α concentrations and the number of CD3+TNF-α+ T-cells, which were negatively correlated with the expression of claudin-1, occludin, and ZO-1, through CD73 in the colon tissue of GVHD mice. Meanwhile, hPMSCs reduced the mean fluorescence intensity (MFI) of reactive oxygen species (ROS) and the concentration of malondialdehyde (MDA), promoted superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) activities, as well as claudin-1, occludin, and ZO-1 expression, in colonic epithelial cells of GVHD mice and TNF-α-stimulated cells via CD73. Moreover, hPMSCs upregulated adenosine (ADO) concentrations in GVHD mice and TNF-α-stimulated cells and mitigated the loss of tight junction proteins via the CD73/ADO/ADO receptors. Further analysis showed that hPMSCs diminished Fyn expression and enhanced Nrf2, GCLC, and HO-1 expression in both TNF-α-stimulated cells and colonic epithelial cells of GVHD mice by activating PI3K/Akt/GSK-3ß pathway. CONCLUSIONS: The results suggested that hPMSC-mediated redox metabolism balance and promoted tight junction protein expression were achieved via CD73/ADO/PI3K/Akt/GSK-3ß/Fyn/Nrf2 axis, by which alleviating intestinal oxidative injury in GVHD mice.

Human umbilical cord-derived mesenchymal stromal cells for the treatment of steroid refractory grades III-IV acute graft-versus-host disease with long-term follow-up.

Introduction: Mesenchymal stromal cells (MSCs) have been extensively studied as a potential treatment for steroid refractory acute graft-versus-host disease (aGVHD). However, the majority of clinical trials have focused on bone marrow-derived MSCs. Methods: In this study, we report the outcomes of 86 patients with grade III-IV (82.6% grade IV) steroid refractory aGVHD who were treated with human umbilical cord-derived mesenchymal stromal cells (UC-MSCs). The patient cohort included 17 children and 69 adults. All patients received intravenous infusions of UC-MSCs at a dose of 1 × 106 cells per kg body weight, with a median of 4 infusions (ranging from 1 to 16). Results: The median time between the onset of aGVHD and the first infusion of UC-MSCs was 7 days (ranging from 3 to 88 days). At day 28, the overall response (OR) rate was 52.3%. Specifically, 24 patients (27.9%) achieved complete remission, while 21 (24.4%) exhibited partial remission. The estimated survival probability at 100 days was 43.7%. Following a median follow-up of 108 months (ranging from 61 to 159 months), the survival rate was approximately 11.6% (10/86). Patients who developed acute lower GI tract and liver GVHD exhibited poorer OR rates at day 28 compared to those with only acute lower GI tract GVHD (22.2% vs. 58.8%; p= 0.049). No patient experienced serious adverse events. Discussion: These finding suggest that UC-MSCs are safe and effective in both children and adults with steroid refractory aGVHD. UC-MSCs could be considered as a feasible treatment option for this challenging conditon. (NCT01754454).

Bacteroides ovatus alleviates dysbiotic microbiota-induced graft-versus-host disease.

Acute lower gastrointestinal GVHD (aLGI-GVHD) is a serious complication of allogeneic hematopoietic stem cell transplantation. Although the intestinal microbiota is associated with the incidence of aLGI-GVHD, how the intestinal microbiota impacts treatment responses in aLGI-GVHD has not been thoroughly studied. In a cohort of patients with aLGI-GVHD (n = 37), we found that non-response to standard therapy with corticosteroids was associated with prior treatment with carbapenem antibiotics and a disrupted fecal microbiome characterized by reduced abundances of Bacteroides ovatus. In a murine GVHD model aggravated by carbapenem antibiotics, introducing B. ovatus reduced GVHD severity and improved survival. These beneficial effects of Bacteroides ovatus were linked to its ability to metabolize dietary polysaccharides into monosaccharides, which suppressed the mucus-degrading capabilities of colonic mucus degraders such as Bacteroides thetaiotaomicron and Akkermansia muciniphila, thus reducing GVHD-related mortality. Collectively, these findings reveal the importance of microbiota in aLGI-GVHD and therapeutic potential of B. ovatus.

Melphalan Dose in Combination With Fludarabine Affects Gastrointestinal Toxicity and Graft-Versus-Host Disease After Allogeneic Transplantation in Acute Myeloid Leukemia and Myelodysplastic Syndromes.

Fludarabine (Flu) and melphalan (Mel) reduced-intensity conditioning is frequently used for allogenic hematopoietic cell transplant (allo-HCT) in patients with acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS). However, there is limited evidence on the impact of Mel dosing on toxicities and clinical outcomes of allo-HCT. We retrospectively compared 8/8 HLA-matched donor allo-HCT outcomes of 345 patients with AML or MDS receiving total Mel dose of 100 mg/m2 (Mel-100, n = 62) versus 140 mg/m2 (Mel-140, n = 283) in combination with Flu. Median age at allo-HCT was 66 years and median follow-up was 36.5 months. For Mel-100 versus Mel-140 groups, any grade gastrointestinal (GI) toxicity rates were 40.3% versus 67.8% (P < .001), day 100 grade II to IV acute graft-versus-host disease (GVHD) rates were 21.0% versus 43.1% (P = .001) and 2-year chronic GVHD rates were 17.4% versus 27.1% (P = .033). In multivariable analysis, Mel-140 resulted in higher risks of GI toxicity (HR = 1.83, P = .013), grade II to IV acute GVHD (HR=2.35, P = .003), and moderate/severe chronic GVHD (HR = 3.13, P = .007). Total Mel dose had no independent impact on oral mucositis, nonrelapse mortality, relapse, relapse-free survival, and overall survival. While independent validation of our observation is warranted, our findings support using Mel-100 in combination with Flu to minimize allo-HCT toxicities and morbidities related to GVHD.

Predictors of fluid overload in allogeneic hematopoietic cell transplant patients receiving post-transplant cyclophosphamide.

BACKGROUND: Fluid overload (FO) commonly occurs during hospitalization for allogeneic hematopoietic cell transplantation (HCT). Grade 2-4 FO is associated with day +100 non-relapse mortality.1 Post-transplant cyclophosphamide (PTCY) for graft-versus-host disease prevention requires aggressive IV hydration to prevent hemorrhagic cystitis. MATERIALS AND METHODS: This is a single-center, retrospective, observational study conducted at an academic medical center via electronic chart review. Included patients received allogeneic HCT followed by PTCY on days +3 and +4. Patients were excluded for age < 18 years or incarceration. Primary endpoints are incidence of Grade 2-4 FO and associated risk factors. Descriptive and inferential statistics (i.e., Fisher's exact test, multivariable regression analysis) were used. RESULTS: Of 97 patients screened, 95 were included and 2 were excluded due to absence of weight measurements needed to grade FO. Median age was 60 years, 66.3% were male, 91.6% received reduced-intensity conditioning, 72.6% received haploidentical HCT, 44.2% were ECOG 0, and 11.6% had diastolic dysfunction. Incidence of grade 2-4 FO was 33.7% (n = 32). Univariate analyses found age (continuous; p = 0.04) and BSA < 1.7 m2 (p = 0.006) as independent factors associated with grade 2-4 FO. Multivariable regression analysis found 3.3% higher risk with every 1-year increase in age ranging from f 20 to 78 years (OR 1.033, 95% CI 1.001, 1.006; p = 0.0453) and 82.8% lower risk with BSA ≥ 1.7 m2 (OR 0.172, 95% CI 0.051, 0.588; p = 0.005) after adjusting for co-variates. CONCLUSION(S): Increasing age and BSA < 1.7 m2 are risk factors associated with grade 2-4 FO during hospitalization for allogeneic HCT with PTCY.

Initiation of Haploidentical Stem Cell Transplantation With Post-Transplant Cyclophosphamide in Children: A Low-Middle-Income Country Institutional Experience.

BACKGROUND: Haploidentical hematopoietic stem cell transplant (HSCT) is a curative treatment especially for countries where bone marrow registries are nonexistent. We present our experience with haploidentical HSCT in pediatric patients. METHODS: Retrospective data collected and analyzed for patients ≤18 years, from January 2017 to December 2022. RESULTS: The cohort consisted of 20 patients with median age at transplant of 61.5 (IQR: 124) months. Fourteen (70%) were malignant and 6 (30%) were benign diseases. Donors were father in majority (9/20; 45%). Stem cell source was peripheral blood 8, marrow 8, and combined 4. c-specific antibodies were positive in 6 (30%). Median CD34 cell dose infused: 9.35 × 106/kg. Median engraftment time: 15 (IQR: 17) days. Acute and chronic graft-versus-host disease (GVHD) occurred in 12/20 (60%) and 5/20 (25%), respectively. Complications included infection/sepsis (14/20; 70%), cytomegalovirus reactivation (14/20; 70%), sinusoidal obstruction syndrome (1/20; 5%), primary graft failure (PGF) (6/20; 30%), and secondary graft failure (4/20; 20%). PGF was more common in benign conditions (p = 0.003) and less prevalent in cases with aGVHD (p = 0.007). aGVHD was more common in malignant conditions (p = 0.007). Overall survival (OS), relapse-free survival (RFS), and treatment-related mortality (TRM) were 40%, 50%, and 35%, respectively. Median time of survival and relapse were 8 (IQR: 15) and 9 (IQR: 13) months, respectively. CONCLUSION: OS was comparable to that of other low-middle-income countries. GVHD was a major challenge, along with sepsis and CMV infection. Half of the leukemias relapsed. Graft failure was a major concern in nonmalignant diseases.

Expansion and characterization of immune suppressive CD56(bright)Perforin(-) regulatory-like natural killer cells in chronic graft-versus-host disease.

BACKGROUND: Chronic graft-versus-host disease (cGvHD) is a major cause of morbidity and mortality after Hematopoietic Stem Cell Transplantation (HSCT). Previously, in large patient cohorts, we identified increased numbers of CD56brightPerforin- regulatory-like NK cells (NKreg-like) associated with cGvHD suppression. Thus, we hypothesized that NKreg-like cells may be a potential candidate for cGvHD cell therapy. AIM: To expand NKreg-like cells while maintaining regulatory phenotype and function. METHODS: Total NK cells were first expanded with IL-2, which was then combined with rapamycin, Transforming Growth Factor Beta 1 (TGF-ß1), NECA (Adenosine A2A receptor (A2AR) agonist), metformin, or dexamethasone, to prevent change in cell phenotype/function. The functional characteristics were evaluated via T cell suppression assays and the phenotype was measured using flow cytometry. The optimal expansion protocol was compared in terms of function and metabolism for three NK expansion media, and cells from cord vs. peripheral blood. Further, expanded NKreg-like cell gene expression was characterized using bulk RNA sequencing. Finally, NKreg-like cells were differentiated from CD34+ hematopoietic stem and progenitor cells (HSPCs) and compared in terms of proliferation and function. RESULTS: The expansion of total NK cells found the addition of TGF-ß1 and/or NECA with the pulsing of rapamycin in IL-2 containing media to prevent NKreg-like differentiation (up to 200-fold expansion). Expanded NKreg-like cells maintained a phenotype, transcriptome, and T cell suppression similar to freshly isolated NKreg-like cells. NKreg-like expansion was greatest in the Immunocult media (up to 300-fold), and NKreg-like cells from peripheral blood demonstrated significantly greater proliferation than cells isolated from cord blood (65-fold). The metabolic profile of NKreg-like and cytolytic NK cells appeared similar at baseline, though rapamycin induced a shift to oxidative over glycolytic metabolism. Further, we demonstrated that suppressive NKreg-like cells may alternatively be expanded from CD34+ cells isolated from cord blood, reaching an average 340-fold expansion. CONCLUSIONS: In conclusion, our studies have optimized two alternative expansion approaches for deriving functional NKreg-like cells. Additionally, evaluating the transcriptomic and metabolic characteristics provides useful information regarding NKreg-like cell function and differentiation. With further optimization and in vivo validation, we may work towards preparing these cells as a therapy for cGvHD.

[Chinese expert consensus on the diagnosis and treatment of acute graft-versus-host disease after hematopoietic stem cell transplantation (2024)].

Despite the continuous improvement in the efficacy of allogeneic hematopoietic stem cell transplantation (allo-HSCT), acute graft-versus-host disease (GVHD) remains a major complication and cause of death. In recent years, with the emergence of new drugs for the prevention and treatment of acute GVHD and the update of a series of clinical studies, there have been varying degrees of changes in the routine prevention and treatment regimens for acute GVHD. Based on the main research achievements and the accumulation of clinical experience in this field in recent years, this consensus further updates the "The Consensus on Allogeneic Hematopoietic Stem Cell Transplantation for Hematological Diseases in China-Acute Graft-Versus-Host Disease (2020) .

Graft-versus-host disease in patients with bone marrow transplants: A retrospective study analyzing outcomes and healthcare burden in US hospitals.

BACKGROUND: Graft-versus-host disease (GVHD) is a recognized complication among individuals undergoing bone marrow transplantation (BMT). There is a requirement for supplementary data regarding the in-patient outcomes of GVHD in individuals who have undergone BMT. Our analysis seeks to assess the healthcare burden and outcomes associated with GVHD in hospitalized patients who have undergone BMT. METHOD: In this retrospective study, we used data from the National Inpatient Sample (NIS) database spanning from 2016 to 2019. Utilizing ICD-10 codes, we distinguished hospitalizations related to BMT and grouped them into two categories: those with GVHD and those without GVHD. Our areas of focus included in-hospital mortality, length of stay, charges, and associations related to GVHD. Unadjusted odds ratios/coefficients were computed through univariable analysis, followed by adjusted odds ratios (aORs)/coefficients from multivariable analysis that considered potential confounding factors. RESULTS: From 2016 to 2019, data were collected from 13,999 hospitalizations with bone marrow transplants. Among them, 836 had GVHD cases. Patient characteristics showed slight differences in mean age and demographics between the two groups, with GVHD patients having a mean age of 51.61 years and higher percentages of males and whites. Analyzing outcomes, patients with GVHD experienced significantly longer hospital stays (41.4 days vs. 21.3 days) and higher total hospital charges ($824,058 vs. $335,765). Adjusting for confounding factors, GVHD posed a substantial risk. The aOR for mortality in GVHD hospitalizations was 7.20 (95% CI: 5.54-9.36, p < .001). The coefficient for the length of stay was 19.36 days (95% CI: 17.29-21.42, p < .001), and the coefficient for total hospital charges was $453,733 (95% CI: $396,577 to $510,889, p < .001) in GVHD cases. Furthermore, GVHD in patients was associated with elevated risks of various medical conditions. The aORs for sepsis, pneumonia, acute respiratory failure, intubation and mechanical ventilation, Clostridium difficile infection, and acute kidney injury (AKI) in GVHD patients were 2.79 (95% CI: 2.28-3.41, p < .001), 3.30 (95% CI: 2.57-4.24, p < .001), 5.10 (95% CI: 4.01-6.49, p < .001), 4.88 (95% CI: 3.75-6.34, p < .001), 1.45 (95% CI: 1.13-1.86, p = .003), and 3.57 (95% CI: 2.97-4.29, p < .001). CONCLUSION: GVHD in individuals undergoing BMT is linked to elevated mortality rates, prolonged hospitalization, and higher healthcare costs. Moreover, they face a significantly increased risk of developing complications, such as sepsis, pneumonia, acute respiratory failure, C. difficile infection, and AKI. These results underscore the critical need for vigilant monitoring and effective GVHD management to improve patient outcomes and reduce the complications associated with BMT. Nevertheless, further prospective studies are essential to obtain a more profound understanding and a comprehensive assessment of outcomes in these hospitalized patients.

Phototherapy for the treatment of cutaneous graft-versus-host disease: A systematic review.

BACKGROUND: Cutaneous graft-versus-host disease (GVHD) is a common complication of allogeneic hematopoietic stem cell transplantation. Phototherapy has been used to treat cutaneous GVHD, but data on its safety and efficacy are sparse. AIM: Review the current medical literature regarding the efficacy, dosing, and safety of various types of phototherapies for the treatment of cutaneous GVHD. METHODS: A systematic review of PubMed, Embase, Cochrane, and ClinicalTrials databases was performed. Publications were screened according to the PRISMA guidelines. Exclusion criteria comprised case reports and case series reporting less than five patients, review articles, and articles not published in English. RESULTS: A total of 28/1304 (2.5%) studies were included. Fifteen studies (n = 267 patients) focused on psoralen and ultraviolet (UV) A (PUVA), in which 65.5% of patients received concomitantly other systemic treatments. The response rate was 89.9%, with a mean of 33.2 treatments. Adverse events were recorded in 54% but were mainly mild. Eight studies, encompassing 95 patients, focused on narrow-band (NB) UVB. A response was observed in 94%, with a mean number of 26 treatments and 8.6% adverse effects. UVA1 was reported in six studies (n = 132 patients). A response was recorded in 89.3% with a mean of 26.2 treatments. Adverse events were noted in 70.1%, with a discontinuation rate of 10.9%. It should be noted that adverse events were recorded during the follow-up period of the studies, which varied significantly, ranging from no follow-up to 31 months. CONCLUSIONS: Current data regarding the use of phototherapy for the treatment of cutaneous GVHD are based on retrospective studies and case series. The present report advocates the use of one of the three modalities of phototherapy as an effective and safe adjunctive treatment for cutaneous GVHD, especially NB UVB phototherapy.

Early intervention with oral mucosal barrier Protective agents in chronic oral graft-versus-host disease: a retrospective cohort study.

BACKGROUND: Preventing the progression of chronic oral graft-versus-host disease (cGVHD) is essential for maintaining oral health, improving quality of life, minimizing functional impairment, reducing systemic complications, and addressing treatment challenges. PURPOSE: To evaluate the effectiveness of early intervention with oral mucosal barrier protective agents in preventing the progression of cGVHD and its impact on oral health, quality of life, and treatment response. METHODS: This retrospective cohort study included 75 participants, with 34 in the non-oral mucosal barrier protective agent group and 41 in the oral mucosal barrier protective agent group. Baseline characteristics, oral mucosal health parameters, quality of life assessments, and curative effect data were collected and compared between the two study groups. RESULTS: The group receiving oral mucosal barrier protectants (n = 41) exhibited significantly lower severity of oral mucositis compared to the group without such protectants (n = 34) (2.12 ± 0.48 vs. 2.56 ± 0.63, P = 0.001) and the incidence of complications was significantly lower in the group receiving oral mucosal barrier protectants (P < 0.05). Additionally, the quality of life assessment showed marked improvements in somatization, emotional management, and social reintegration in the oral mucosal barrier protectant group compared to the group without these protectants (P < 0.05). Furthermore, the assessment of treatment efficacy revealed significantly higher rates of both complete and partial responses in the oral mucosal barrier protectant group, along with a notable reduction in disease progression compared to the group without these protectants (P < 0.001). CONCLUSION: Early intervention with oral mucosal barrier protective agents was associated with improved oral health parameters, enhanced quality of life, and a more favorable treatment response in the context of cGVHD.

Efficacy of a modified post-transplant cyclophosphamide regimen for unrelated donor hematopoietic stem cell transplantation in patients with severe aplastic anemia: A prospective study.

The aim of the present study was to examine the efficacy of the modified post-transplant cyclophosphamide (PTCy) regimen, which involved reducing the Cy dose to 40 mg on days +3 and +4, in patients with severe aplastic anemia (SAA) subjected to unrelated donor allogeneic hematopoietic stem cell transplantation (URD-HSCT). For this purpose, a prospective single-center trial was conducted and the clinical outcomes were collected from 30 patients with SAA treated with the modified PTCy regimen for URD HSCT. The median time to neutrophil and platelet engraftment was 13 days (range, 11 to 16) and 12 days (range, 5 to 33), respectively. The cumulative incidence of neutrophil and platelet engraftment was 93.1±0.3% and 96.6±0.2%, respectively. The 2-year overall survival (OS) was 97% [95% confidence interval (CI): 90%-100%] and 2-year graft-versus-host disease (GVHD) and rejection-free survival (GRFS) was 93% (95% CI: 85%-100%). The incidence rates of acute GVHD (aGVHD) and chronic GVHD (cGVHD) were 13.8±0.4% and 10.3±0.3%, respectively, and no patients developed grade III-IV aGVHD. However, only one patient developed a moderate extensive cGVHD. The incidence of reconstitution varies among different subsets of immune cells after URD HSCT. Natural killer (NK) cells first recover, followed by CD8+ T and CD19+ B cells, and finally CD4+ T cells. In conclusion, the present study demonstrates that the modified PTCy regimen, with a reduced dose of 40mg on days +3 and +4, may be an effective regimen for URD HSCT in patients with SAA and reduce the occurrence of the GVHD.

Clinical impact of airflow obstruction after allogeneic hematopoietic stem cell transplantation.

Criteria for airflow obstruction (AFO) at one year after allogeneic hematopoietic stem cell transplantation (allo-HSCT) in pulmonary function tests (PFTs) are more stringent than the bronchiolitis obliterans syndrome (BOS) criteria of the National Institutes of Health. This single-center, retrospective cohort study evaluated the clinical impact of the AFO criteria at any time after transplantation. In 132 patients who underwent allo-HSCT from 2006 to 2016, the 2-year cumulative incidence of AFO was 35.0%, and the median time to diagnosis of AFO was 101 days after transplantation (range 35-716 days). Overall chronic graft-versus-host disease (cGVHD) incidence was significantly higher in patients with AFO than in those without AFO (80.4% vs. 47.7%, P < 0.01); notably, 37.0% of patients with AFO developed cGVHD after AFO diagnosis. AFO patients developed BOS with a 5-year cumulative incidence of 49.1% after AFO onset. The 5-year cumulative incidence of non-relapse mortality in the AFO group was higher than that in the non-AFO group (24.7% vs. 7.1%, P < 0.01). These results suggest that closely monitoring PFTs within two years after allo-HSCT, regardless of cGVHD status, is important for early detection of AFO and prevention of progression to BOS. (192words).

Better clinical outcomes and lower triggering of inflammatory cytokines for allogeneic hematopoietic cell transplant recipients treated in home care versus hospital isolation - the Karolinska experience.

After allogeneic hematopoietic cell transplantation (Allo-HCT) and conditioning, patients are typically placed in isolated hospital rooms to prevent neutropenic infections. Since 1998, we've offered an alternative: home care for patients living within a one to two-hour drive of the hospital. In Sweden this approach includes daily visits by an experienced nurse and daily phone consultations with a unit physician. When necessary, patients receive transfusions, intravenous antibiotics, and total parenteral nutrition at home. Our initial study report compared 36 home care patients with 54 hospital-treated controls. Multivariate analysis found that home care patients were discharged earlier to outpatient clinics, required fewer days of total parenteral nutrition, had less acute graft-versus-host disease (GVHD) grade II-IV, and lower transplantation-related mortality (TRM) and lower costs. Long-term follow-up showed similar chronic GVHD and relapse rates in both groups, with improved survival rates in the home care group. A subsequent comparison of 146 home care patients with hospital-treated controls indicated that home care and longer home stays were associated with lower grades of acute GVHD. Home care was found to be safe and beneficial for children and adolescents. Over two decades, 252 patients received home care post-Allo-HCT without any fatalities at-home. Ten-year outcomes showed a 14% TRM and a 59% survival rate. In 2020, an independent center confirmed the reduced risk of acute GVHD grades II-IV for patients treated in home care. Here, we report for the first time that home care patients also demonstrate a less inflammatory systemic cytokine profile. We found higher levels of IFN-γ, IL-2, IL-5, IL-13, GM-CSF, and G-CSF, but lower VEGF in hospital-treated patients, which may contribute to acute GVHD grades II-IV. In conclusion, home-based treatment following Allo-HCT yields multiple promising clinical outcomes and improved systemic inflammatory markers, which may contribute to less development of life-threatening GVHD.

Uncommon finding in a pulmonary graft versus host disease: A first report of Tsukamurella pneumonia in a pulmonary graft-versus-host disease.

A 64-year-old woman presented to Our Department with 2 weeks history of fever and cough. Through a series of radiological and invasive diagnostic studies we finally reach an unexpected diagnosis of Tsukamurella pneumonia; Diagnosing an ILD is a dynamic process, and that is the reason why complex cases discussed in a multidisciplinary team may need to be reconsidered in light of evolution of the disease and the results of the performed exams with a flexible approach. Tsukamurella spp. is an obligate aerobic, Gram-positive, weakly acid-fast, non-motile bacillus that belongs to the order Actinomycetales. Pneumonia caused by Tsukamurella is exceedingly rare, and only few cases are reported in the literature. Our aim is to evidence the paramount importance of Multidisciplinary team discussion in deciding the most appropriate diagnostic is of and therapeutical strategy.

Lower incidence of grade II-IV acute Graft-versus-Host-Disease in pediatric patients recovering with high Vδ2+ T cells after allogeneic stem cell transplantation with unmanipulated bone marrow grafts: a prospective single-center cohort study.

Gamma delta (γδ) T cells represent a minor fraction of human T cell repertoire but play an important role in mediating anti-infectious and anti-tumorous effects in the context of allogeneic hematopoietic stem cell transplantation (allo-HSCT). We performed a prospective study to analyze the effect of different transplant modalities on immune reconstitution of γδ T cells and subsets. CD3, CD4 and CD8 T cells were analyzed in parallel. Secondly, we examined the impact of γδ T cell reconstitution on clinical outcomes including acute Graft-versus-Host-Disease (aGvHD) and viral infections. Our cohort includes 49 pediatric patients who received unmanipulated bone marrow grafts from matched unrelated (MUD) or matched related (MRD) donors. The cohort includes patients with malignant as well as non-malignant diseases. Cell counts were measured using flow cytometry at 15, 30, 60, 100, 180 and 240 days after transplantation. Cells were stained for CD3, CD4, CD8, CD45, TCRαß, TCRγδ, TCRVδ1, TCRVδ2, HLA-DR and combinations. Patients with a MRD showed significantly higher Vδ2+ T cells than those with MUD at timepoints +30, +60, +100 (p<0.001, respectively) and +180 (p<0.01) in univariate analysis. These results remained significant in multivariate analysis. Patients recovering with a high relative abundance of total γδ T cells and Vδ2+ T cells had a significantly lower cumulative incidence of grade II-IV aGvHD after transplantation (p=0.03 and p=0.04, respectively). A high relative abundance of Vδ2+ T cells was also associated with a lower incidence of EBV infection (p=0.02). Patients with EBV infection on the other hand showed higher absolute Vδ1+ T cell counts at days +100 and +180 after transplantation (p=0.046 and 0.038, respectively) than those without EBV infection. This result remained significant in a multivariate time-averaged analysis (q<0.1). Our results suggest a protective role of γδ T cells and especially Vδ2+ T cell subset against the development of aGvHD and EBV infection after pediatric HSCT. Vδ1+ T cells might be involved in the immune response after EBV infection. Our results encourage further research on γδ T cells as prognostic markers after HSCT and as possible targets of adoptive T cell transfer strategies.

Epidemiology of Diffuse Alveolar Hemorrhage in Pediatric Allogeneic Hematopoietic Cell Transplantation Recipients.

Diffuse alveolar hemorrhage (DAH) is a life-threatening pulmonary toxicity that can arise after hematopoietic cell transplantation (HCT). Risk factors and outcomes are not well understood owing to a sparsity of cases spread across multiple centers. The objectives of this epidemiologic study were to characterize the incidence, outcomes, transplantation-related risk factors and comorbid critical care diagnoses associated with post-HCT DAH. Retrospective analysis was performed in a multicenter cohort of 6995 patients age ≤21 years who underwent allogeneic HCT between 2008 and 2014 identified through the Center for International Blood and Marrow Transplant Research registry and cross-matched with the Virtual Pediatric Systems database to obtain critical care characteristics. A multivariable Cox proportional hazard model was used to determine risk factors for DAH. Logistic regression models were used to determine critical care diagnoses associated with DAH. Survival outcomes were analyzed using both a landmark approach and Cox regression, with DAH as a time-varying covariate. DAH occurred in 81 patients at a median of 54 days post-HCT (interquartile range, 23 to 160 days), with a 1-year post-transplantation cumulative incidence probability of 1.0% (95% confidence interval [CI], .81% to 1.3%) and was noted in 7.6% of all pediatric intensive care unit patients. Risk factors included receipt of transplantation for nonmalignant hematologic disease (reference: malignant hematologic disease; hazard ratio [HR], 1.98; 95% CI, 1.22 to 3.22; P = .006), use of a calcineurin inhibitor (CNI) plus mycophenolate mofetil (MMF) as graft-versus-host disease (GVHD) prophylaxis (referent: CNI plus methotrexate; HR, 1.89; 95% CI, 1.07 to 3.34; P = .029), and grade III-IV acute GVHD (HR, 2.67; 95% CI, 1.53-4.66; P < .001). Critical care admitted patients with DAH had significantly higher rates of systemic hypertension, pulmonary hypertension, pericardial disease, renal failure, and bacterial/viral/fungal infections (P < .05) than those without DAH. From the time of DAH, median survival was 2.2 months, and 1-year overall survival was 26% (95% CI, 17% to 36%). Among all HCT recipients, the development of DAH when considered was associated with a 7-fold increase in unadjusted all-cause post-HCT mortality (HR, 6.96; 95% CI, 5.42 to 8.94; P < .001). In a landmark analysis of patients alive at 2 months post-HCT, patients who developed DAH had a 1-year overall survival of 33% (95% CI, 18% to 49%), compared to 82% (95% CI, 81% to 83%) for patients without DAH (P < .001). Although DAH is rare, it is associated with high mortality in the post-HCT setting. Our data suggest that clinicians should have a heightened index of suspicion of DAH in patients with pulmonary symptoms in the context of nonmalignant hematologic indication for HCT, use of CNI + MMF as GVHD prophylaxis, and severe acute GVHD. Further investigations and validation of modifiable risk factors are warranted given poor outcomes.

Traversing the bench to bedside journey for iNKT cell therapies.

Invariant natural killer T (iNKT) cells are immune cells that harness properties of both the innate and adaptive immune system and exert multiple functions critical for the control of various diseases. Prevention of graft-versus-host disease (GVHD) by iNKT cells has been demonstrated in mouse models and in correlative human studies in which high iNKT cell content in the donor graft is associated with reduced GVHD in the setting of allogeneic hematopoietic stem cell transplants. This suggests that approaches to increase the number of iNKT cells in the setting of an allogeneic transplant may reduce GVHD. iNKT cells can also induce cytolysis of tumor cells, and murine experiments demonstrate that activating iNKT cells in vivo or treating mice with ex vivo expanded iNKT cells can reduce tumor burden. More recently, research has focused on testing anti-tumor efficacy of iNKT cells genetically modified to express a chimeric antigen receptor (CAR) protein (CAR-iNKT) cells to enhance iNKT cell tumor killing. Further, several of these approaches are now being tested in clinical trials, with strong safety signals demonstrated, though efficacy remains to be established following these early phase clinical trials. Here we review the progress in the field relating to role of iNKT cells in GVHD prevention and anti- cancer efficacy. Although the iNKT field is progressing at an exciting rate, there is much to learn regarding iNKT cell subset immunophenotype and functional relationships, optimal ex vivo expansion approaches, ideal treatment protocols, need for cytokine support, and rejection risk of iNKT cells in the allogeneic setting.