Successful Hematopoietic Stem Cell Transplantation Research Articles

Cardiac Arrhythmias and Mortality after Hematopoietic Stem Cell Transplant (HSCT): A Systematic Review and Meta-Analysis

IntroductionHematopoietic stem cell transplant (HSCT) is commonly performed for the treatment of advanced hematological malignancies. Emerging data suggest non-relapse related events, including cardiac arrhythmias, increasingly limit anticancer outcomes and non-relapse mortality after initially successful HSCT. Yet, the relationship between HSCT and increased risk of arrhythmias after transplant remains controversial and unclear. Our aim was to evaluate the incidence and effect on mortality risk of arrhythmia development after HSCT.Materials and methodsLeveraging the PubMed, Embase, Cochrane, Scopus and Clinicaltrials.gov databases, we identified all published studies evaluating the incidence and impacts of early arrhythmias after HSCT from January 1995 to July 2021 using PRISMA guidelines. We included all available observational studies (case-control, and cohort) and clinical trials without restriction of language or country of publication. The primary outcome was incidence of atrial fibrillation (AF) at 1 year of follow-up after HSCT. Secondary outcomes included the incidence of any arrhythmia across follow-up, the incidence of left atrium (LA) dilation, and non-relapse mortality associated with HSCT induced AF. Subgroup analysis based on type of HSCT treatment employed, allogenic (Allo-HSCT) or autologous (Auto-HSCT), was also performed. Variance weighted random effects modeling (DerSimonian and Laird) was used to define the associations between HSCT and AF and mortality events. Outcomes were reported as event rates, and relative risks (RR). Medians were reported with corresponding standard errors (SE). Heterogeneity was assessed using Cochrane Q-statistic which was quantified with I 2test (>75% was considered high heterogeneity). Publication bias was assessed using Eager's test where applicable. Further, the quality of included studies was assessed using the New-Castle Ottawa scale.ResultsOverall, from 769 articles, 12 cohort studies inclusive of 6,371 patients meeting study-criteria were identified. The mean incidence of AF was 8.8% (I 2:97%, P<0.001), including 5.2% (I 2:65%, P=0.05) within 1-year of any HSCT. The overall incidence of any type of arrhythmia was 11.2% (I 2 =95%, P≤0.001); Figure. Median time to AF onset was 10.3 days (SE= 1.2), but was longer in those treated with Allo-HSCT, at 71 days (SE=68.4); P<0.05. Among those treated with Allo-HSCT, 8.2% (I 2:73%, P<0.001) developed AF, including 6.5% (I 2:72%, P<0.01) at 1 year; the event rate for any type of arrhythmia was 8.3% (I 2:52%, P<0.001). In those treated with Auto-HSCT, the rate of AF was 8.7% (I 2=97%, P≤0.001) across follow-up. Among those with AF following HSCT therapy, LA dilatation was observed in 37.2% (I 2 =61.5%, P=0.1) among available studies. Similarly, mortality was higher among patients who developed AF vs. those without AF after HSCT (RR: 7.4, P=0.008, I 2 = 92.87). There was low risk of publication bias as assessed by visual inspection of funnel plot and Egger's regression test (P= 0.21); and low risk of bias within the included studies.ConclusionAtrial fibrillation is increasingly common after HSCT therapy, and associates with increased mortality. The presence of LA remodeling, reflected by atrial dilation, appears to portend AF risk. Further research into the mechanisms and predictors of AF after HSCT are needed. [Display omitted] DisclosuresVasu: Kiadis, Inc.: Research Funding; Boehringer Ingelheim: Other: Travel support; Seattle Genetics: Other: travel support; Omeros, Inc.: Membership on an entity's Board of Directors or advisory committees. Saad: Incyte Pharmaceuticals: Consultancy; careDx: Consultancy; Amgen: Research Funding; Kadmon: Research Funding; OrcaBio: Research Funding; Magenta Therapeutics: Consultancy. de Lima: Miltenyi Biotec: Research Funding; BMS: Membership on an entity's Board of Directors or advisory committees; Pfizer: Membership on an entity's Board of Directors or advisory committees; Incyte: Membership on an entity's Board of Directors or advisory committees. Jaglowski: Juno: Consultancy; Novartis: Consultancy, Research Funding; Kite, a Gilead Company: Consultancy, Research Funding; Takeda: Consultancy; CRISPR Therapeutics: Consultancy.

Microtubule Polymerization Inhibition Enhances Human Hematopoietic Stem Cell Homing and Engraftment

Hematopoietic stem cells (HSCs) serve as the origin of the hematopoietic system, with the ability to differentiate into all blood cell lineages and self-renewal to sustain the hematopoiesis throughout life. Hematopoietic stem cell transplantation (HSCT) currently represents the most effective therapeutic strategies to treat hematological and non-hematological diseases. However, limited numbers of HSCs or poor homing capabilities into the bone marrow are still major hurdles for successful HSCT. Moreover, graft failure and delayed reconstitution due to inefficient engraftment, remains an important complication because of the high morbidity and mortality. Although ex vivo expansion of HSCs has been well studied for decades, which displays huge potentials for clinical application, exploration of novel targets to improve HSC homing and engraftment will provide new insights to enhance HSCT efficacy.To explore the chemical compounds enhancing the capabilities of homing and engraftment, we used CXCR4 (CD184) as the readout bio-marker, which is considered as the most essential chemokine receptor of HSPCs interacting with CXCL12 (SDF1) secreted in BM niche to support HSPCs homing, migration, proliferation and survival. We first performed chemical screening of 139 small molecules that can increase CD184 expression on cord blood (CB) CD34 + hematopoietic stem and progenitor cells (HSPCs). We concluded that treatment of CB CD34 + HSPCs for 16 hours with Lexibulin (Lex) or Vinblastine Sulfate (VS), both of which were microtubule polymerization (MP) inhibitors, could significantly promote the CD184 expression.Next, we optimized the MP inhibitors treatment conditions including dosage, treatment duration and culture time prior to treatment. The results proved that treatment with Lex or VS for 16 hours at 1μM was the optimal conditions to significantly enhance the CD184 expression of CD34 + HPSCs and LT-HSCs (CD34 +CD90 +CD45RA -), while maintaining robust cell survival, when compared with the DMSO control group. Moreover, we found that only when HSPCs were under culture within two days prior to small molecules treatment, CD184 expression was significantly increased by MP inhibitors while maintaining high viability, compared with DMSO control group.In order to assess the in vivo repopulating potential of the CB CD34 + HSPCs post treatment with MP inhibitors, we transplanted CB-HSPCs 16 hours post-treatment with Lex and VS respectively into irradiated nonobese diabetic (NOD)/Prkdc scid/IL-2Rγ null (NPG) mice. All transplanted mice of MP inhibitors-treated groups presented efficient engraftment, in multiple immune organs at 4-16 weeks post-transplantation, suggesting greater engraftment potential than the mock group, as measured by human CD45 of total CD45. Furthermore, hematopoietic reconstitution analysis indicated that the MP inhibitors -treated cells maintained different lineage distribution in peripheral blood (PB), bone marrow (BM) and spleen. Moreover, the equivalent phenotypes of pre- and post-treatment reveal the better reconstitution by MP inhibitors was independent of HSC-enrichment, Thus, short-term MP inhibitors treatment of CB CD34 + HSPCs enhances their homing and long-term engraftment.In conclusion, we demonstrated that short-term microtubule polymerization inhibition on human CB CD34 + HSPCs could not only enhance CD184 cell surface expression but also the capabilities of in vivo human HSCs homing and reconstitution via screening chemical compounds to increase CD184 expression and the following function evaluation study. Vinblastine Sulfate and Lexbulin were applied or registered as anti-cancer drugs for clinical use. Our study also indicates that MP inhibitors pretreatment of cells possesses significant translational implications, designating MP inhibitors as promising drug candidates to facilitate clinical HSCT. [Display omitted] DisclosuresFang: EdiGene, Inc.: Current Employment.

Early diagnosis of Wiskott-Aldrich syndrome in the neonatal period and successful haematopoietic stem cell transplant in infancy

Wiskott-Aldrich syndrome (WAS) is a rare X-linked inborn error of immunity characterised by triad of eczema, microthrombocytopenia and recurrent infections. We herein report a case, where a male new-born with thrombocytopenia and no other symptoms was suspected of WAS in view of the significant family history of two previous sibling deaths. The diagnosis was confirmed by flowcytometry for WAS protein expression. He was initially managed with intravenous immunoglobulin replacement, regular cotrimoxazole prophylaxis, emollients and topical steroids for eczema (which child developed from the third month). The child underwent haematopoietic stem cell transplant (HSCT) at 8 months of age successfully and has remained asymptomatic at 5 years of follow-up. Early diagnosis of inborn error of immunity is extremely important for the prevention of complications and successful treatment including HSCT.

Hematopoietic stem cell mobilization.

ABSTRACTHematopoietic stem cell (HSC) transplantation has been used to treat hematopoietic diseases for over 50 years. HSCs can be isolated from bone marrow (BM), umbilical cord blood, or peripheral blood. Because of lower costs, shorter hospitalization, and faster engraftment, peripheral blood has become the predominant source of HSCs for transplantation. The major factors determining the rate of successful HSC transplantation include the degree of human leukocyte antigen matching between the donor and recipient and the number of HSCs for transplantation. Administration of granulocyte colony-stimulating factor (G-CSF) alone or combined with plerixafor (AMD3100) are clinical used methods to promote HSC mobilization from BM to the peripheral blood for HSC transplantations. However, a significant portion of healthy donors or patients may be poor mobilizers of G-CSF, resulting in an insufficient number of HSCs for the transplantation and necessitating alternative strategies to increase the apheresis yield. The detailed mechanisms underlying G-CSF-mediated HSC mobilization remain to be elucidated. This review summarizes the current research on deciphering the mechanism of HSC mobilization.

Efficacy of peripheral arterial access for peripheral blood stem cells collection.

Transplantation of peripheral blood stem cells (PBSCs) mobilized by cytokines is increasingly applied to treat patients with hematologic diseases, such as lymphoma, multiple myeloma, leukemia, etc. Successful hematopoietic stem cell transplantation (HSCT) increasingly depends on the collection of hematopoietic stem cells (HSCs) from peripheral blood. Peripheral vein (PV) is the most common type of blood access. When the blood vessels are not well filled and the blood flow is insufficient, the machine will appear repeated low pressure alarm or pipeline coagulation, which seriously affects the collection efficiency. A peripheral artery (PA) is utilized for drawing blood, while a peripheral vein is used for blood return, that is a way to perform apheresis. The advantages of PA are that it ensures adequate extracorporeal circulation blood flow, stable blood flow rate, simple operation, and relatively low price. However, there are very few studies on the efficacy of peripheral arterial access for HSCs collection. Therefore, this retrospective study was conducted to assess the effectiveness of PA and PV access for PBSCs collection. We performed a retrospective analysis of 150 apheresis procedures on 26 patients and 95 healthy donors collected by PV or PA access from March 1, 2020 to March 1, 2021. We compared the CD34+ cell count, collection efficiency (CE), duration of processing a single blood volume, number of low-pressure alarms, average blood flow rate and number of punctures between the two groups. Also, we analyzed adverse events. There was no significant difference in the quality of apheresis blood components between the PA group and the PV group. The CD34+ cells collected was 274.16 ± 216.31 × 106 in the PV group and 246.63 ± 127.94 × 106 in the PA group. The CE in the PA group was 49.50 ± 9.88%, higher than 42.39 ± 14.62% in the PV group. The duration of processing a single blood volume was 90.67 ± 15.35 min in the PV group and 79.68 ± 10.28 min in the PA group. The number of low-pressure alarms in the PA group was 0.38 ± 0.98, <2.42 ± 1.76 in the PV group, and the average blood flow rate in the PA group was 59.27 ± 2.18, higher than 54.21 ± 3.41 in the PV group. The difference was statistically significant (P < .05). The Number of punctures was 1.35 ± 0.75 in the PA group and 1.41 ± 1.01 in the PV group. There was no statistically significant difference. Peripheral artery is a safe, reliable, economical, convenient, and fast vascular access, which opens a new way to the establishment of vascular access for PBSCs collection.

Low Rates of Cerebral Infarction after Hematopoietic Stem Cell Transplantation in Patients with Sickle Cell Disease at High Risk for Stroke

Hematopoietic stem cell transplantation (HSCT) can be curative for sickle cell disease (SCD). SCD patients with cerebrovascular disease are often referred for HSCT. The objective of this study was to describe neurologic outcomes after HSCT in patients with pre-existing SCD and cerebrovascular comorbidity. Patients with SCD treated with HSCT at a single center between 1996 and 2019 were identified. Patients with cerebral ischemia and/or vasculopathy before undergoing HSCT were included. Patients with graft failure were excluded. The cohort was divided into 3 groups: symptomatic stroke, vasculopathy without symptomatic stroke, and isolated silent cerebral infarction (SCI). Magnetic resonance imaging/angiography and neurologic assessments pre- and post-HSCT were analyzed to assess outcomes. In a cohort of 44 patients, there were 25 with symptomatic infarction, 10 with vasculopathy, and 9 with isolated SCI. Post-HSCT ischemic injury (2 symptomatic strokes, 2 SCIs) was identified in 4 patients, all with previous symptomatic infarction. Within this group (n=25), the post-HSCT incidence of subsequent symptomatic infarction was 1.6 events/100 patient-years, and SCIs occurred at a rate of 2.2 events/100 patient-years. No patient had progression of vasculopathy post-HSCT. Our data show a low incidence of new ischemic injury after successful HSCT for SCD. Patients with a history of both symptomatic stroke and vasculopathy are at greatest risk for post-HSCT ischemic injury.

Novel Insights Into the Mechanism of GVHD-Induced Tissue Damage.

Prophylaxis for and treatment of graft-versus-host disease (GVHD) are essential for successful allogeneic hematopoietic stem cell transplantation (allo-SCT) and mainly consist of immunosuppressants such as calcineurin inhibitors. However, profound immunosuppression can lead to tumor relapse and infectious complications, which emphasizes the necessity of developing novel management strategies for GVHD. Emerging evidence has revealed that tissue-specific mechanisms maintaining tissue homeostasis and promoting tissue tolerance to combat GVHD are damaged after allo-SCT, resulting in exacerbation and treatment refractoriness of GVHD. In the gastrointestinal tract, epithelial regeneration derived from intestinal stem cells (ISCs), a microenvironment that maintains healthy gut microbiota, and physical and chemical mucosal barrier functions against pathogens are damaged by conditioning regimens and/or GVHD. The administration of growth factors for cells that maintain intestinal homeostasis, such as interleukin-22 (IL-22) for ISCs, R-spondin 1 (R-Spo1) for ISCs and Paneth cells, and interleukin-25 (IL-25) for goblet cells, mitigates murine GVHD. In this review, we summarize recent advances in the understanding of GVHD-induced tissue damage and emerging strategies for the management of GVHD.

Simultaneous enumeration of CD34+ and CD45+ cells using EasyCounter image cytometer

Accurate counting of CD34-positive cells is important for successful hematopoietic stem cell transplantation that is applied to various diseases. The aim of this study was simultaneous counting of viable CD34+ (vCD34+) and CD45+ (vCD45+) cells in apheresis samples by automatic immunofluorescence counter – EasyCounter BC. CD34+ and CD45+ cells were counted using two conjugates anti-CD34 antibody – dR110 and anti-CD45 antibody – ATTO620, respectively. The conjugates were prepared by carbodiimide method. Dead nuclear cells were counted by using monomethine cyanine dye PO-TEDM 1. The linearity and reproducibility of EasyCounter BC for CD34+ cell counting were determined (R2 = 0.99; CV values for vCD34+ cells were 6.8 ÷ 8.5% and for vCD45+ cells 4.1 ÷ 7.2%). The obtained results by EasyCounter BC were compared with those by other two standard methods – flow cytometry (Guava easyCyte 8HT) and fluorescence microscopic method (Olympus BX51) with the same conjugates. Passing–Bablok regression was performed to determine the relationship between the results of the three methods, analyzing 43 apheresis samples. Correlation coefficients for vCD45+ and vCD34+ between EasyCounter BC and Olympus microscope were 0.987 and 0.982, respectively (P < 0.0001). Better results were obtained between EasyCounter BC and flow cytometer Guava, 0.998 for vCD45+ and 0.998 for vCD34+ (P < 0.0001).

Hematopoietic stem cell transplantation in a patient with proteasome-associated autoinflammatory syndrome (PRAAS)

Proteasome-associated autoinflammatory syndromes (PRAASs) form a family of recently described rare autosomal recessive disorders of disturbed proteasome assembly and proteolytic activity caused by mutations in genes coding for proteasome subunits. The treatment options for these proteasome disorders consist of lifelong immunosuppressive drugs or Janus kinase inhibitors, which may have partial efficacy and noticeable side effects. Because proteasomes are ubiquitously expressed, it is unknown whether hematopoietic stem cell transplantation (HSCT) may be a sufficient treatment option. Our aim was to report the case of a young boy with a treatment-resistant cutaneous vasculitis that was initially suspected to be associated with a gene variant in SH2D1A. Whole-exome sequencing was performed to identify the genetic defect. Molecular and functional analyses were performed to assess the impact of variants on proteasomal function. The immune characterization led to the decision to perform HSCT on our patient and conduct follow-up over the 7-year period after the transplant. Because loss of myeloid chimerism after the first HSCT was associated with relapse of autoinflammation, a second HSCT was performed. After the successful second HSCT, the patient developed mild symptoms of lipodystrophy, which raised the suspicion of a PRAAS. Genetic analysis revealed 2 novel heterozygous variants in PSMB4 (encoding proteasomal subunit β7). Retrospective analysis of patient cells stored before the first HSCT and patient cells obtained after the second HSCT demonstrated that HSCT successfully rescued proteasome function, restored protein homeostasis, and resolved the interferon-stimulated gene signature. Furthermore, successful HSCT alleviated the autoinflammatory manifestations in our patient. Patients with treatment-resistant PRAAS can be cured by HSCT.

Successful hematopoietic stem cell transplantation for acute myelomonocytic leukemia in a patient with active pulmonary tuberculosis

A 45-year-old woman presented with acute myelomonocytic leukemia (AMML) with a 54% blast count. The patient developed frank hemoptysis during cycle 1 of consolidation therapy with cytarabine and midostaurin following induction chemotherapy with cytarabine and idarubicin. Sputum collected at that time was mycobacterial smear negative but culture identified drug-sensitive pulmonary tuberculosis (TB). Since she had AMML with a high risk for relapse, allogeneic hematopoietic stem cell transplant (HSCT) was planned. In consultation with TB services, the transplant occurred after 45 days of TB treatment. We report a successful HSCT in a patient while undergoing treatment for active TB.

Normalization of Cerebral Hemodynamics after Hematopoietic Stem Cell Transplant in Children with Sickle Cell Anemia

▪BackgroundChildren with Sickle Cell Anemia (SCA) are at high risk for overt or silent strokes, and this risk may be mitigated by hematopoietic stem cell transplant (HSCT). Our research group has shown that when cerebral oxygen delivery is compromised due to anemia in SCA, the cerebral blood flow (CBF) and brain oxygen extraction fraction (OEF) increase to maintain brain tissue oxygen delivery. We used novel magnetic resonance imaging (MRI) sequences to measure OEF and CBF in children with SCA treated with HSCT, testing the hypothesis that after HSCT, OEF and CBF will be similar to control values.MethodsChildren with SCA were enrolled in a pilot prospective, observational study of MRI-measured OEF and CBF. Brain MRI exams were performed without sedation on a 3T Siemens scanner. The MRI protocol included fluid-attenuated inverse recovery (FLAIR) sequences in two planes to evaluate for strokes, asymmetric spin echo to measure tissue-level OEF, and pseudo-continuous arterial spin labeling perfusion-weighted imaging to measure CBF. HSCT recipients underwent paired brain MRI 1-2 months before and >1 year after HSCT. Controls, non-anemic siblings of SCA patients, had a single brain MRI. Pre- and post-HSCT CBF and OEF were compared within subjects and between the HSCT and control cohorts using non-parametric tests. Bivariate correlations between OEF or CBF and hemoglobin (Hb) or Hb S concentrations were tested with Spearman's rho. The level of significance was specified as p < 0.05 after adjustment by the Benjamini-Hochberg procedure.ResultsFour children (two male, median age 10 years, range 8-21 years) underwent HSCT: one had prior overt stroke, one had silent strokes, and two had no neuroimaging abnormalities. All received a reduced intensity preparative regimen of alemtuzumab, melphalan, and fludarabine. One subject received marrow from an HLA-matched unrelated donor without Hb S trait; two received marrow from HLA-identical siblings. One child who had rejected a HSCT from an HLA-identical sibling underwent re-conditioning with antithymocyte globulin and cyclophosphamide and received CD-34-selected peripheral stem cells from the same donor. All sibling donors had Hb S trait. Brain MRIs of 20 non-anemic sibling controls of median age 11 years (range 6-17 years) were included for comparison.Median OEF and CBF were significantly elevated pre-HSCT compared to controls (OEF median 0.355 vs 0.288, p = 0.012; CBF median 99.8 vs 65.1 ml/100 g/min, p = 0.018; Figure). Median post-HSCT OEF and CBF were lower than pre-HSCT values (OEF median 0.270 vs 0.355, CBF median 65.1 vs 99.8 ml/100 g/min, p = 0.13 for both), but these analyses had low power to detect significant differences due to the small sample size. Post-HSCT, recipients' OEF and CBF were similar to controls (OEF median 0.270 vs 0.288, p=0.18; CBF median CBF 65.1 vs 75.8 ml/100 g/min, p = 0.42). None of the HSCT recipients had new overt or silent strokes on FLAIR imaging or developed severe acute or chronic GVHD after HSCT.Pre-HSCT, recipients were anemic compared to controls (median Hb 9.8 vs 12.8 g/dl, p = 0.018). Pre-HSCT Hb S concentrations were lower than expected for SCA due to recent red blood cell transfusions (median 50.6%, range 39.7-77.6%). At the post-HSCT imaging timepoint, recipients' anemia had resolved (median Hb 12.4 g/dl, range 11.3-15.7 g/dl), and Hb S concentrations were consistent with their donors' levels. When all pre- and post-HSCT measurements were compared, OEF had a strong negative correlation with Hb (Spearman's rho = -0.905, p = 0.002) and a strong positive correlation with Hb S concentration (Spearman's rho = 0.970, p < 0.001). CBF had a weaker negative correlation with Hb (Spearman's rho = -0.714, p = 0.047) and positive correlation with Hb S concentration (Spearman's rho = 0.731, p = 0.040).ConclusionIn this cohort, children with SCA had normalization of OEF and CBF after successful HSCT. OEF elevation was strongly correlated with Hb S concentration and inversely correlated with Hb concentration in these HSCT recipients. Our data suggest that when curative HSCT corrects hemolytic anemia, OEF and CBF normalize. This physiologic change may provide protection against strokes following HSCT for SCA. [Display omitted] DisclosuresHulbert:Pfizer: Other: Spouse employment at Pfizer. Fields:Proclara Biosciences: Equity Ownership.

Poor Outcome of Domino Hematopoietic Stem Cell Transplantation in Humans - an International Case Series

BackgroundDomino hematopoietic stem cell transplantation (HSCT) refers to a situation where an HSCT recipient serves as the donor for another (HLA-identical) recipient. Several successful cases have been reported, suggesting that acquired tolerance to HLA-antigens in the first recipient allows for engraftment in the second recipient, with low risk of graft-versus-host disease (GvHD). However, no systematic analyses on the outcome of domino HSCT have been performed.MethodsA retrospective, questionnaire-based study was performed within the European Bone Marrow Transplant (EBMT) network and the Primary Immune Deficiency Treatment Consortium (PIDTC). Primary outcome measures were survival and re-transplantation; secondary outcome measures were incidence of GvHD and time to neutrophil and platelet engraftment.FindingsWe identified 11 domino-HSCTs performed in 9 different centers, between September, 1992 and March, 2016. Indications were immune deficiency (n=9), inborn errors of metabolism (n=1) and hereditary bone marrow failure (n=1). The outcome of domino recipients was poor and inferior to their donors and to published cases. Only five recipients (45%) survived with long-term donor engraftment, of whom one required repeated donor-lymphocyte infusions. Four recipients (36%) required re-transplantation and two (18%) engrafted but died from infectious complications. The time between domino-HSCT and re-transplantation ranged up to 190 months. No differences were found in CD34+ cell dose, total nucleated cell dose, nor in kinetics of engraftment between successful domino HSCTs and those resulting in re-transplantation. One domino recipient and six primary recipients developed GvHD.InterpretationThis study demonstrates the disappointing outcome of domino-HSCT. Alternative donor sources, if available, should be considered. Replicative stress on the transplanted stem cells, loss of “stem-ness”, and immune-mediated mechanisms may contribute to the limited engraftment upon serial transplantation. In addition, our results stress the importance of systematic evaluation of published and unpublished cases for unbiased clinical decision making. DisclosuresCowan:Homology Medicine: Consultancy.

Long-Term Follow-Up of Ruxolitinib in the Treatment of Steroid-Refractory Chronic Graft-versus-Host Disease

Chronic graft-versus-host disease (cGVHD) remains a major barrier to successful hematopoietic stem cell transplantation (HSCT). In cases refractory to first-line therapy with steroids, there is no standard of care for second-line therapy. As such, ruxolitinib is a promising drug in this scenario. We retrospectively analyzed the efficacy and safety of ruxolitinib in treating steroid-refractory cGVHD in 35 patients from 2 transplantation centers, with the longest follow-up described to date. The evaluated patients had a median of 3 organs affected (range, 1 to 7 organs), with most (64%) having moderate cGVHD. The median number of previous therapy lines was 2 (range, 1 to 6). The overall response rate was 89% (complete response, 26%) after a median of 4 weeks of therapy. The median follow-up was 43 months (range, 11 to 59 monts). At follow-up, of the 27 patients still alive, 18 (67%) were free of any immunosuppression, and 6 (22%) were receiving ruxolitinib as their sole immunosuppressive drug. Failure-free survival was 77.1% at 6 months, 68.6% at 12 months, 54% at 24 months, and 51.4% at 36 months. The median overall survival was not reached. Toxicities were mostly hematologic and resolved after dosage reduction in most cases. Overall, our data, which represent the cohort of patients with cGVHD treated with ruxolitinib with the longest follow-up to date, support the use of this drug as a safe and effective option for refractory cGVHD.

Demographic and Clinical Donor Characteristics as Predictors of Total Nucleated Cell Concentrations in Harvested Marrow Products

Successful allogeneic hematopoietic stem cell transplantation (alloHSCT) relies significantly on adequate allograft cell composition to achieve sustained engraftment, and a minimum of 2×108 total nucleated cells (TNCs) per kilogram of recipient body weight has been identified as the prerequisite cell dose for successful engraftment of marrow-derived products. To meet this minimum requirement, marrow harvest volumes are estimated based on anticipated TNC concentrations of 18.3×106/mL. However, there is considerable variability in marrow TNC concentrations. Thus, an algorithm that incorporates baseline donor characteristics to predict TNC concentrations could optimize outcomes for both donors and recipients. For this study, donor baseline characteristics and corresponding unstimulated marrow products harvested between 2004 and 2017 at a single large-volume donor center were collected. Multivariable analysis was used to identify significant predictors of TNC concentration. Two models-ordinary least squares (OLS) and least absolute shrinkage and selection operator (LASSO) regression-were compared for their fitness to the data and their utility in predicting TNCs. Donors with higher body mass index, younger age, male sex, white race/ethnicity, smaller harvest volumes, lower preharvest hematocrit, higher preharvest platelet count, and higher preharvest WBC count predicted significantly higher TNC concentrations in marrow products. When comparing predictive models that incorporate these characteristics, the cross-validated LASSO and bootstrapped OLS provided the best fit. We now supply these formulas to be validated in other datasets before clinical use. TNC concentration in marrow products can be predicted using donor characteristics, most of which are readily available during the donor clinical assessment. The ability to predict marrow allograft TNC concentrations can optimize collection volumes during a harvest.

Successful rescue of a lethal Griscelli syndrome type 2 presenting with neurological involvement and hemophagocytic lymphohistiocytosis: a case report

BackgroundGriscelli syndrome type 2 (GS2) is a rare autosomal recessive disease caused by mutations in RAB27A gene. It is primarily characterized by a combination of partial albinism, hemophagocytic lymphohistiocytosis (HLH) or other immunodeficiency. However, neurological involvement at onset in GS2 and treatment has rarely been described.Case presentationWe describe a 3-year-old boy with GS2 in an Asian Chinese family. He presented with progressive neurological abnormalities following unremitting fever at onset. He developed HLH during the clinical course. A novel homozygous mutation (c.1 A > G) in RAB27A gene was subsequently identified. He was then treated by HLH-1994 protocol combined with ruxolitinib and experienced a dramatic remission. He subsequently underwent a successful haploidentical hematopoietic stem cell transplantation and stayed at a good condition.ConclusionsWe reported an atypical form of GS2 manifesting as severe central nervous system involvement at onset and subsequent HLH, which was successfully rescued in time. This case also highlights the need for early consideration of immunologic and genetic evaluation for HLH in unexplained neuroinflammation in the diagnostic work up.

Health assessment in patients with autosomal recessive osteopetrosis before and after allogeneic hematopoietic stem cell transplantation

Here we report the results of long-term monitoring of children with malignant infantile osteopetrosis (MIOP) before and after a successful hematopoietic stem cell transplantation (HSCT). We present patient health data collected 3-6 years after the completion of treatment, including information on the children's physical and mental health and social adaptation. The study was approved by the Independent Ethics Committee and the Scientifi Council of the N.I. Pirogov Russian National Research Medical University of Ministry of Healthcare of the Russian Federation. HSCT is the only currently available radical treatment for MIOP. At the time of the treatment, all the patients exhibited severe visual impairment (descending optic atrophy), transfusiondependent bone marrow dysfunction, hepatosplenomegaly, signifiant skeletal abnormalities and growth retardation. In this study, we included 5 MIOP patients with successful transplantation who had been treated from 2014 to 2018. Four patients underwent HSCT from unrelated 10/10 HLA-identical donors and 1 patient received HSCT from a related 10/10 HLA-identical donor. The ratio of boys to girls was 2:3, the median age at the time of the transplantation was 7 (2–11) years. All the patients demonstrated full donor chimerism after HSCT. Hematopoietic recovery was achieved within the fist 150 days after HSCT. Radiological investigations showed gradual partial reduction of skeletal changes typical of MIOP. All the subjects demonstrated growth of the axial skeleton, facial bone remodeling and abatement of phenotypic features of the disease. The patients' vision remained the same as before HSCT. All the patients reported that their health and quality of life had improved after HSCT. The degree of visual impairment had a substantial impact on the quality of life and social rehabilitation of the patients. The second major factor affcting the quality of life was the development of chronic conditions after HSCT, namely, epilepsy and chronic “graft-versus-host” disease of the lung that require constant medical monitoring and limit rehabilitation potential. The patients' parents gave their consent to the use of their children's data, including photographs, for research purposes and in publications.

Biomarkers for Early Complications of Endothelial Origin After Allogeneic Hematopoietic Stem Cell Transplantation: Do They Have a Potential Clinical Role?

Endothelial cell (EC) dysfunction causes a number of early and life-threatening post hematopoietic stem cell transplant (HCT) complications that result in a rapid clinical decline. The main early complications are graft-vs.-host disease (GVHD), transplant associated thrombotic microangiopathy (TA-TMA), and sinusoidal obstruction syndrome (SOS). Post-HCT endothelial dysfunction occurs as a result of chemotherapy, infections, and allogeneic reactivity. Despite major advances in transplant immunology and improvements in supportive care medicine, these complications represent a major obstacle for successful HCT. In recent years, different biomarkers have been investigated for early detection of post-transplant endothelial cell dysfunction, but few have been validated. In this review we will define GVHD, TA-TMA and SOS, summarize the current data available in HCT biomarker research and identify promising biomarkers for detection and diagnosis of early HCT complications.

HLA-A gene knockout using CRISPR/Cas9 system toward overcoming transplantation concerns

BackgroundThe treatment of many cancers and genetic diseases relies on novel engraftment approaches such as cell therapy and hematopoietic stem cell transplantation (HSCT). However, these methods are hindered by the alloreactive immune responses triggered by incompatible human leukocyte antigen (HLA) molecules. A successful HSCT procedure requires the eradication of donor and recipient HLA alloimmunization. Eliminating HLA-A gene expression using clustered regularly interspaced short palindromic repeats/CRISPR-associated protein 9 nuclease (CRISPR/Cas9) could be a great approach to increase the possibility of a successful HSCT through extending pool of unrelated donors.ResultsOur dual gRNA approach introduced a large deletion in the HLA-A gene. Among 22 single-cloned cells, two clones (9.09%) and 11 clones (50%) received homozygous and heterozygous large deletions, respectively. Finally, the real-time PCR results also revealed that HLA-A gene expression was diminished significantly.ConclusionThe results suggested that CRISPR/Cas9 could be used as an efficient technique to introduce HLA-A gene knockout; thus, it can considerably lessen the burden of finding a fully matched donor by lowering the alleles required for a successful HSCT.

Switching from Intravenous to Oral Tacrolimus Reduces its Blood Concentration in Paediatric Cancer Patients.

Tacrolimus is an essential immunosuppressant for successful allogeneic haematopoietic stem cell transplantation (Allo-HSCT). This study aimed to examine the change in the blood concentration of tacrolimus during switching from intravenous to oral administration in allo-HSCT for paediatric cancer to predict the optimal dosage. We retrospectively examined the medical records of 63 patients who received allo-HSCT and were administered tacrolimus. To compare bioavailability among different dose ranges, the blood concentration was divided by the dose (C/D). Thirty-nine patients (age range=children 1-15 years, adults 17-67 years) were switched to oral administration of tacrolimus. The C/D after switching was significantly lower in children than in adults (p=0.039). There was a strong positive correlation between age and C/D in children, whereas no correlation was observed in adults. In paediatric cancer patients, switching tacrolimus administration route may result in reduced blood concentrations. This tendency is more prominent in younger children.

HLA-haploidentical TCRαβ+/CD19+-depleted stem cell transplantation in children and young adults with Fanconi anemia

AbstractWe report on the outcome of 24 patients with Fanconi anemia (FA) lacking an HLA matched related or unrelated donor, given an HLA-haploidentical T-cell receptor αβ (TCRαβ+) and CD19+ cell-depleted hematopoietic stem cell transplantation (HSCT) in the context of a prospective, single-center phase 2 trial. Sustained primary engraftment was achieved in 22 (91.6%) of 24 patients, with median time to neutrophil recovery of 12 days (range, 9-15 days) and platelet recovery of 10 days (range, 7-14 days). Cumulative incidences of grade 1 to 2 acute graft-versus-host disease (GVHD) and chronic GVHD were 17.4% (95% confidence interval [CI], 5.5%-35.5%) and 5.5% (95% CI, 0.8%-33.4%), respectively. The conditioning regimen, which included fludarabine, low-dose cyclophosphamide and, in most patients, single-dose irradiation was well tolerated; no fatal transplant-related toxicity was observed. With a median follow-up of 5.2 years (range, 0.3-8.7 years), the overall and event-free survival probabilities were 100% and 86.3% (95% CI, 62.8%-95.4%), respectively (2 graft failures and 1 case of poor graft function were considered as events). The 2 patients who experienced primary graft failure underwent a subsequent successful HSCT from the other parent. This is the first report of FA patients given TCRαβ+/CD19+-depleted haplo-HSCT in the context of a prospective trial, and the largest series of T-cell–depleted haplo-HSCT in FA reported to date. This trial was registered at www.clinicaltrials.gov as #NCT01810120.