Efficiency of allogeneic hematopoietic SCT from HLA fully-matched non-sibling relatives: a new prospect of exploiting extended family search

Comparing between HLA-matched sibling donor allogenic HSCT and non-sibling matched related donor allogenic HSCT outcome in pediatric patients; single center retrospective study

BACKGROUND

Extended family donor search other than siblings may yield an HLA matched donor in communities with high rate of consanguinity. The outcome of patients who are transplanted from non-sibling matched related donors (NS-MRD) including engraftment and graft versus host disease (GVHD) are scarce in comparison with matched sibling donor (MSD).

METHODS

We retrospectively reviewed the outcome of all our pediatric hematopoietic stem cell transplantation (HSCT) patients who had non-sibling matched related donor and controlled them with matched sibling donor HSCT (based on age, indication of HSCT, conditioning regimen, GVHD prophylaxis, serotherapy, stem cell source and cytomegalovirus status).

RESULTS

A total of 76 patients were reviewed during study period. Thirty patients (39.5%) in NS-MRD arm and 46 patients in MSD (60.5%) were identified after matching in age, disease, and conditioning regimens. All patients had similar approach including stem cell source and GVHD prophylaxis (CNI + 2nd agent). Out of the NS-MRD group, 18 patients (59%) had one of their parents as a donor and the rest as second degree relatives. Both groups were equally distributed and were homogeneous. Both groups had no statistically significant difference in outcome including engraftment, GVHD and Chimerism tests results. GVHD was seen in (13%) NS-MRD patients compared to (11%) in MSD patients. All patients remain alive with median follow up of 1249 days (431-3525).

CONCLUSIONS

This study showed no significant difference in allogenic HSCT outcomes between matched sibling donors and non-sibling matched related donors and support using the same management approach in terms of conditioning therapy, GVHD prophylaxis, and serotherapy only if indicated.

Five novel HLA-A, -B, and -C alleles identified in Brazilian individuals by next-generation sequencing

The novel HLA-A*11:379, B*45:01:11, B*15:571, B*57:137, C*07:893 alleles were identified in Brazilian individuals.

Strategic priorities for hematopoietic stem cell transplantation in the EMRO region

The World Health Organization-designated Eastern Mediterranean region (EMRO) consists of 22 countries in North Africa and Western Asia with a collective population of over 679 million. The area comprises some of the wealthiest countries per capita income and some of the poorest. The population structure is also unique and contrasts with western countries, with a much younger population. The region sits in the heart of the thalassemia belt. Many countries have a significant prevalence of sickle cell disease, and cancer is on the rise in the region. Therefore, the strategic priorities for the growth and development of hematopoietic stem cell transplantation (HSCT) differ from country to country based on resources, healthcare challenges, and prevalent infrastructure. Thirty-one reporting teams to the Eastern Mediterranean Blood and Marrow Transplantation Group have active HSCT programs in 12 countries; allogeneic transplants outnumber autologous transplants, and the proportion of allotransplants for non-malignant conditions is higher in the EMRO region than in Western Europe and North America. The vast majority (99%) of allotransplants are from matched related donors. Matched unrelated donors and other alternate donor transplants are underutilized. The chance of finding a matched related donor for allografts is higher, with a significant chance of finding matched donors among non-sibling related donors. Reasons for relatively lower rates of transplants compared with other countries are multifactorial. Capacity building, development of newer centers, innovative funding, and better utilization of information technology are required to make transplantation as an accessible modality to more patients. Cost-effectiveness and cost-containment, regulation, and ensuring quality will all be priorities in planning HSCT development in the region.

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

Background

The 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.

Results

Our 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.

Conclusion

The 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.

Comparison of Hematopoietic Stem Cell Transplantation Results in Patients with β-Thalassemia Major from Three Different Graft Types

Allogeneic hematopoietic stem cell transplantation (HSCT) is the curative therapy for β-thalassemias that induces severe life-threatening complications. The human leukocyte antigen (HLA) registries and umbilical cord blood banks have carried out diligent searches to find matched unrelated donors (MUDs) for about 70.0% of patients from 2000 onwards. The chance of finding a non-sibling fully matched family donors is higher in some ethnic groups in which consanguineous marriages are common. We have studied and compared transplant complications and outcomes in different graft types (sibling, non-sibling family and unrelated). The non-sibling matched family donor (MFD) group consisted of four mothers, three fathers, five cousins, one paternal uncle and one paternal aunt. There was no significant difference in the mean transfused CD34+ cells, engraftment, median days of neutrophil and platelet recovery were achieved (p > 0.05). The distribution of postttransplant complication did not show any significant difference between groups (p > 0.05). In univariate analysis and multivarite analyses, age, gender, Pesaro risk group (I-II vs. III) and ABO incompatibilty demonstrated a significant difference in disease free survival (p < 0.05). Furthermore, in the second step of investigating overall survival (OS), age, gender and Pesaro risk group (I-II vs. III) showed a significant difference (p < 0.05). There was no significant difference in transplant-related mortality (TRM) between groups. Non-sibling related donor transplants are important for populations where consanguineous marriages are common. Transplant groups according to graft type had similar thalassemia-free survival (TFS) and OS when using a treosulfan-based regimen in our study.

Outcomes Following Allogeneic Stem Cell Transplantation Using Non-sibling Family Donors

For patients requiring allogeneic stem cell transplant, in the absence of a HLA-matched sibling, an extended donor search within the family may yield a suitable donor especially in societies with a high prevalence of consanguinity. We describe outcomes in transplants with non-sibling family donors, and compare outcomes with controls having a sibling donor transplant. Retrospective analysis of all matched related (non-sibling) donor transplants between 1995 and 2015. For comparison, appropriate age, sex and disease-matched patients were chosen from the sibling transplants (MSD) performed during the same time period (± 2 years). Comparison between the fully matched non-sibling donor cohort and age, sex and disease-matched sibling donor transplants showed a significant increase in complications in the family donor group (viral infections, acute GVHD and rejection). Event-free survival and overall survival were significantly lower in the non-sibling donor cohort, and HLA disparity (1-2 antigen) further worsened the adverse impact. Though there was a significantly lower event-free and overall survival at 3 years in the family donor cohort, this did not retain significance in the multivariate analysis. This data on allogeneic transplants using family donors showed higher complication rates and poorer outcomes. However in situations where financial constraints prevent access to matched unrelated donor sources, extended family searches may be fruitful in yielding a donor, and modifications in conditioning regimens and improvement in supportive care may help in improving the outcomes in family donor transplants.

Cell-based and pharmacological neurorestorative therapies for ischemic stroke

Ischemic stroke remains one of most common causes of death and disability worldwide. Stroke triggers a cascade of events leading to rapid neuronal damage and death. Neuroprotective agents that showed promise in preclinical experiments have failed to translate to the clinic. Even after decades of research, tPA remains the only FDA approved drug for stroke treatment. However, tPA is effective when administered 3-4.5 h after stroke onset and the vast majority of stroke patients do not receive tPA therapy. Therefore, there is a pressing need for novel therapies for ischemic stroke. Since stroke induces rapid cell damage and death, neuroprotective strategies that aim to salvage or replace injured brain tissue are challenged by treatment time frames. To overcome the barriers of neuroprotective therapies, there is an increasing focus on neurorestorative therapies for stroke. In this review article, we provide an update on neurorestorative treatments for stroke using cell therapy such as bone marrow derived mesenchymal stromal cells (BMSCs), human umbilical cord blood cells (HUCBCs) and select pharmacological approaches including Minocycline and Candesartan that have been employed in clinical trials. This review article discusses the present understanding of mechanisms of neurorestorative therapies and summarizes ongoing clinical trials. This article is part of the Special Issue entitled 'Cerebral Ischemia'.

First report of pediatric hematopoietic stem cell transplantation activities in the eastern mediterranean region from 1984 to 2011: on behalf of the pediatric cancer working committee of the eastern mediterranean blood and marrow transplantation group

To describe the hematopoietic stem cell transplantation (HSCT) activities for children in the Eastern Mediterranean (EM) region, data on transplants performed for children less than 18 years of age between 1984 and 2011 in eight EM countries (Egypt, Iran, Jordan, Lebanon, Oman, Pakistan, Saudi Arabia and Tunisia) were collected. A total of 5187 transplants were performed, of which 4513 (87%) were allogeneic and 674 (13%) were autologous. Overall, the indications for transplantation were malignant diseases in 1736 (38.5%) and non-malignant in 2777 (61.5%) patients. A myeloablative conditioning regimen was used in 88% of the allografts. Bone marrow (BM) was the most frequent source of stem cells (56.2%), although an increasing use of PBSC was observed in the last decade. The stem cell source of autologous HSCT has shifted over time from BM to PBSC, and 80.9% of autologous HSCTs were from PBSCs. The donors for allogeneic transplants were matched-related in 94.5% of the cases, and unrelated transplants, mainly cord blood (99%) in 239 (5.5%) cases. This is the first report to describe the pediatric HSCT activities in EM countries. Non-malignant disorders are the main indication for allogeneic transplantation. Frequency of alternate donor transplantation is low.

Characterization of a new HLA-DRB1 allele: DRB1*14:172

DRB1*14:172 homologous to DRB1*14:01 has been found with a variation in 314 A > G.

Hematopoietic stem cell transplantation from non-sibling matched family donors for patients with thalassemia major in Jordan

There are limited data on the outcome of patients with thalassemia receiving HSCT from non-sibling matched family donors. Of the 341 patients with thalassemia major that underwent donor search at our center from January 2003 to December 2011, 236 (69.2%) had fully matched family donor of which 28 patients (8.2%) had non-sibling matched family donors identified. We report on seven patients with a median age of eight yr (4-21) who underwent myeloablative (n = 4) or RIC (n = 3) HSCT. The median age of the donors was 33 yr (4-47), three were parents, two first cousins, one paternal uncle, and one paternal aunt. All patients achieved primary neutrophil and platelet engraftment at a median of 18 (13-20) and 16 days (11-20), respectively. One patient developed grade II acute GVHD, and two patients developed limited chronic GVHD. One patient experienced secondary GF requiring a second transplant. At a median follow-up of 69 months (7-110), all patients are alive and thalassemia free. Our data emphasize the need for extended family HLA typing for patients with thalassemia major in regions where there is high rate of consanguinity. Transplant from non-sibling matched family donor can result in excellent outcome.

Characterization of a new HLA allele: A*02:548

HLA-A*02:548 differs from A*02:01:01:01 by one nucleotide at position 367T > C resulting in histidine at codon 99.