Optimal graft source for allogeneic hematopoietic stem cell transplant: bone marrow or peripheral blood?

Successful Treatment of Severe Steroid-Resistant Engraftment Syndrome Following Haploidentical Allogeneic Hematopoietic Stem Cell Transplantation for Acute Myeloid Leukemia with Emapalumab: A Case Report

Engraftment syndrome (ES) is an early complication of hematopoietic stem cell transplantation (HSCT) characterized by fever and additional clinical manifestations including rash, diarrhea, lung infiltrates, weight gain, and neurological symptoms. Steroid-resistant ES following HSCT significantly affects the efficacy of transplantation and may even result in patient mortality. As ES essentially represents a cytokine storm induced by engrafted donor cells with interferon-gamma (IFN-γ) playing a central role, we hypothesized that emapalumab (an anti-IFN-γ monoclonal antibody) may be an effective approach to treat steroid-resistant ES. Here, we present a case report of a 14-year-old female patient who received a second haploidentical HSCT due to a relapse of acute myeloid leukemia. Nine days after the transplantation, the patient developed a fever and exhibited a poor response to antimicrobials (ceftazidime/avibactam). A few days later, the patient presented with a new-onset rash, weight gain, and impaired liver function, leading to a diagnosis of ES. Initial immunosuppressive (tacrolimus and mycophenolate mofetil) treatment failed to control the disease. On day 16 post-transplantation, the patient received two infusions of 50 mg of emapalumab. Following the initiation of emapalumab treatment, the patient's fever returned to normal and ES was effectively controlled. This case report demonstrated that emapalumab had a possible efficacy for steroid-resistant ES and provided a novel therapeutic strategy to treat this clinical complication.

Inflammatory monocytes promote pre-engraftment syndrome and tocilizumab can therapeutically limit pathology in patients

Unrelated cord blood transplantation (UCBT) is an effective treatment for hematopoietic disorders. However, this attractive approach is frequently accompanied by pre-engraftment syndrome (PES), severe cases of PES are associated with enhanced mortality and morbidity, but the pathogenesis of PES remains unclear. Here we show that GM-CSF produced by cord blood-derived inflammatory monocytes drives PES pathology, and that monocytes are the main source of IL-6 during PES. Further, we report the outcome of a single arm, single-center clinical study of tocilizumab in the treatment of steroid-refractory severe PES patients (www.chictr.org.cn ChiCTR1800015472). The study met the primary outcome measure since none of the patients was nonrelapse death during the 100 days follow-up. The study also met key secondary outcomes measures of neutrophil engraftment and hematopoiesis. These findings offer a therapeutic strategy with which to tackle PES and improve nonrelapse mortality.

Pre-engraftment syndrome is a major consideration during clinical application of unrelated cord blood transfusion and monocytes represent a critical cell type in immune-pathogenesis. Here the authors further establish the role of monocytes and GM-CSF in pre-engraftment syndrome and show clinical administration of tocilizumab limits pathology in pre-engraftment syndrome pathology in patients.

Comparative profiling of exosomal miRNAs in human adult peripheral and umbilical cord blood plasma by deep sequencing

Aim: To assess differential expression profiles of miRNAs in exosomes derived from human peripheral blood (PB) and umbilical cord blood (UCB). Materials & methods: Small RNA sequencing was performed to characterize the miRNA expression in plasma exosomes processed from UCB of five healthy newborns and PB of five normal adult volunteers, and differentially expressed miRNAs were further analyzed. Results: A total of 65 exosomal miRNAs, including 46 upregulated and 19 downregulated, showed differential expression between UCB and PB. Target genes of these miRNAs were mainly enriched in signaling pathways associated with pregnancy, cancers, cell mobility and nervous system. Conclusion: Exosomal miRNAs may have essential roles in the biological functions of UCB, suggesting the therapeutic and biomarker potentials of exosomes in UCB.

In MDS, is higher risk higher reward?

Patients with higher-risk myelodysplastic syndrome (HR-MDS) are defined by the original or revised International Prognostic Scoring System and specific genetic features. Treatment of HR-MDS is challenging. Allogeneic hematopoietic stem cell transplantation, the only curative approach, is feasible in a minority of fit or intermediate fitness patients aged <70 to 75 years who are willing to face the risks of the procedure. Response to azacitidine and decitabine, the only approved drugs for HR-MDS and considered the standard of care, is partial and transient in most patients. The development of novel more personalized and efficient drugs is an unmet medical need. During the last decade, there have been substantial advances in understanding the multiple molecular, cellular, and immunological disturbances involved in the pathogenesis of myelodysplastic syndrome. As a result, a number of clinical and translational studies of new more focused treatment approaches for HR-MDS patients are underway. In contrast to acute myeloid leukemia, they have not resulted in any new drug approval. This review addresses the benefits and limitations of current treatment alternatives, offers a practical individualized treatment approach, and summarizes the clinical trials in progress for HR-MDS.

Hematopoietic Cell Transplantation for Myelodysplastic Syndromes

Allogeneic hematopoietic cell transplantation (HCT) offers the only potential cure for patients with myelodysplastic syndromes (MDS). However, with current approaches to HCT, many older patients with comorbidities are poor HCT candidates, and treatment-related morbidity and mortality may offset benefit for patients with lower-risk disease. Consequently, selection of patients with MDS for HCT should take into consideration disease risk category including mutational status, HCT comorbidity index, functional status, donor options, and available institutional resources. Formal geriatric assessment may further guide use of HCT and, if HCT is chosen, selection of conditioning intensity. Patients with higher-risk MDS should be considered for HCT at the time of diagnosis, whereas expectant nontransplant management is more appropriate for those with lower-risk disease. A high blast burden at the time of HCT increases the risk of subsequent relapse; however, the role of pretransplant cytoreductive therapy and the regimen of choice remain controversial. Patients with MDS younger than 65 years and with an HCT comorbidity index ≤ 4 may benefit from more intense conditioning regimens. The presence of complex or monosomal karyotype or mutations in TP53, DNMT3A, or other genes identify patients with poorer outcomes following HCT. Patients with TP53 mutations have particularly poor survival, and should be enrolled in clinical trials whenever possible. Several important HCT studies are ongoing and will better define the role of HCT in MDS as well as the value of pretransplant cytoreductive therapy or post-transplant relapse-prevention strategies. Given the apparent underuse of HCT in eligible patients and low enrollment in MDS HCT clinical trials to date, timely referral of patients with MDS to such trials and HCT programs is critical.

Outcomes of haploidentical transplant compared with matched donor allogeneic stem cell transplant

The risk of acute and chronic graft-versus-host disease (GVHD) with haploidentical transplant with post-transplant high-dose cyclophosphamide may be lower compared with matched unrelated donor transplant and largely similar to matched related donor transplant. The lower probability of GVHD with the haploidentical donor may result in a risk of nonrelapse mortality that is at least similar to or even lower than the matched donor. The incidence of relapse and survival are also largely similar to different donor types. Haploidentical transplant may be associated with slower engraftment. Given a lower risk of GVHD, haploidentical transplant has gained popularity. Additionally, the use of post-transplant high-dose cyclophosphamide has been extended to lower the risk of GVHD with matched donor and mismatched unrelated donor transplant.