Following hematopoietic stem cell transplantation (HSCT), it is important to determine whether engraftment is successful and to track the dynamic changes of the graft. Tandem repeats such as minisatellites and microsatellites are currently the most established markers for chimerism application. We have developed a reliable method to quantitatively evaluate engraftment status in post-allogeneic HSCT patients using variable number of tandem repeat (VNTR) markers and "lab-on-a-chip" microfluidic electrophoresis technology. Following identification of an informative marker by conventional polymerase chain reaction (PCR), donor chimerism percentage was calculated based on a standard curve generated from artificially mixed patient-donor DNA-specific alleles in serial dilutions. All PCR products were mixed with commercial gel dye and loaded into Agilent DNA 1000 microfluidic LabChips for DNA sizing and quantitation. In 44 patients, separation of pretransplant and donor DNA fragments was resolved clearly and accomplished rapidly within 30min. Chimerism analysis using this platform is able to detect an amount as low as 6.3% donor DNA with acceptable coefficient of variation values. We also demonstrated concordant chimerism analysis findings using both microchip tandem repeats and real-time PCR quantitation of insertion-deletion polymorphisms. This microchip platform obviates the need for fluorescently labeled primers or any post-PCR sample manipulation. Quantitative monitoring of post-HSCT chimerism status using microfluidic electrophoresis is a useful tool for both large- and small-scale post-HSCT chimerism centers.
The current treatment options for beta thalassaemia major patients include conservative treatment with blood cell transfusions and iron chelation or stem cell transplantation. Regular blood transfusions inevitably lead to multi-organ haemosiderosis and are attended by risks of blood-borne infections. Results from stem cell transplantation are good and suggest that this should be offered as first line therapy when a matched sibling donor is available because the patient is often cured and able to live a normal life. Of 38 Malaysian children who underwent bone marrow or cord blood transplantations using matched sibling donors, 29 (76%) are now cured.
Although survival rates for childhood cancers have improved steadily over the past two decades, the outcome for advanced stage solid tumours remains poor. Many of these tumours are chemosensitive but most chemotherapeutic regimens are limited by their haematological toxicities. Much attention is now focused on mega-dose chemotherapy followed by stem cell rescue in the treatment of disseminated neuroblastoma, rhabdomyosarcoma, germ cell tumour and brain tumours. There is a preferential shift towards peripheral blood stem cell transplantation instead of bone marrow transplantation because of its advantages of faster engraftment, decreased transfusion and antibiotic usage and shortened hospitalisation. This mode of therapy is dependent on technologies including peripheral blood stem cell harvesting, cell cryopreservation and thawing. These technologies were recently made available in Malaysia and we report our early experience.
Allogeneic hematopoietic stem cell transplantation (HSCT) remains a potential curative option for many patients with hematological malignancies (HM). However, the high rate of transplantation-related mortality (TRM) restricted the use of standard myeloablative HSCT to a minority of young and fit patients. Over the past few years, it has become evident that the alloreactivity of the immunocompetent donor cells mediated anti-malignancy effects independent of the action of high dose chemoradiotherapy. The use of reduced intensity conditioning (RIC) regimens has allowed a graft-versus-malignancy (GvM) effect to be exploited in patients who were previously ineligible for HSCT on the grounds of age and comorbidity. Retrospective analysis showed that RIC has been associated with lower TRM but a higher relapse rate leading to similar intermediate term overall and progression-free survivals when compared to standard myeloablative HSCT. However, the long term antitumor effect of this approach is less well established. Prospective studies are ongoing to define which patients might most benefit from reduced toxicity stem cell transplant (RT-SCT) and which transplant protocols are suitable for the different types of HM. The advent of RT-SCT permits the delivery of a potentially curative GvM effect to the majority of patients with HM whose outcome with conventional chemotherapy would be dismal. Remaining challenges include development of effective strategies to reduce relapse rates by augmenting GvM effects without increasing toxicity.
Haematopoietic stem cell transplantation (HSCT) was started in Malaysia since 1993 and it has improved the survival of patients with otherwise fatal haematological diseases. This study was initiated because quality of life of these survivors is an important tool in assessing the outcome of this treatment modality. The secondary objective was to identify factors that influenced their quality of life. The European Organization of Research and Treatment of Cancer Quality of Life Questionnaire (EORTC-30) was used to assess the quality of life of eligible patients. A total of 62 patents were recruited. The mean global health score (QoL) was 71.2. The major symptoms faced by our patients were fatigue, financial difficulty and appetite loss. Appetite loss was an independent adverse factor for lower QoL.
The follow-up of chimerism status after allogeneic haematopoietic stem cell transplantation (HSCT) is essential to predict successful engraftment to assess the development of graft-versus-host disease, graft rejection and disease relapse. Analysis of short tandem repeats (STR) via polymerase chain reaction is frequently used for chimerism determination. However, most commercially-available kits have been designed for forensic purposes and may not be optimal for chimerism analysis. The present study aims to identify suitable STR markers for patient-donor pairs of predominantly Malay and Chinese ethnicity using two commercially-available forensic kits.
Allogeneic bone marrow or peripheral blood stem cell transplantation traditionally uses myeloablative regimen for conditioning to enable grafting of donor's stem cells. Animal experiments have shown that a milder non-myeloablative conditioning regimen does allow engraftment to occur. Nonmyeloablative conditioning regimens are low-intensity immunosuppressive treatment given to the recipient before infusion of donor's stem cells. It was reported to have decreased immediate procedural mortality, in particular those secondary to acute graft versus host reaction. However, it did give rise to higher risks of graft rejection, tumour tolerance and disease progression. Fortunately, appropriately administered donor lymphocyte infusion has been shown to establish full donor chimerism (complete donor stem cell grafting in the recipient's bone marrow) and potentiate antitumour effect (graft versus tumour reaction). The reduction of immediate transplant mortality allows the procedure to be carried out in older age groups, patients with concomitant diseases that otherwise would have made the patients unfit for the procedure, patients with non-malignant disorders such as congenital immune deficiencies, autoimmune disorders or thalassaemia majors. The regimen also allows transplantation of genetically manipulated haemopoietic stem cells (gene thrapy) to be carried out more readily in the immediate future. Lastly, the regimen may serve as a platform for immunotherapy using specific T cell clones for anti-tumour therapy with or without the knowledge of known tumour antigen.
A 25-month-old boy with beta-thalassaemia major was presented with an opportunity for umbilical cord blood transplantation when his unborn sibling was diagnosed in utero to be a beta-thalassaemia carrier and also human leucocyte antigen compatible. A barely adequate amount of cord blood was collected at the birth of his sibling and infused into the patient after appropriate chemo-conditioning. Engraftment occurred without major complications. The subject is now alive and well 9 months post-transplant, thus marking our first success in umbilical cord blood transplantation.
Analysis of variable number tandem repeats (VNTRs) by polymerase chain reaction (PCR) is a common method used to predict engraftment status in post-allogeneic haematopoeitic stem cell transplantation (HSCT) patients. Different populations have different copies of repeated DNA sequence and hence, different percentage of informativeness between patient and donor.
Radioimmunotherapy is an established treatment modality in Non-Hodgkin's lymphoma. The only two commercially available radioimmunotherapies - (90)Y-ibritumomab tiuxetan is expensive and (131)I-tositumomab has been discontinued from commercial production. In resource limited environment, self-labelling (131)I-rituximab might be the only viable practical option. We reported our pioneer experience in Malaysia on self-labelling (131)I-rituximab, substituting autologous haematopoietic stem cell transplantation (HSCT) and a patient, the first reported case, received high dose (131)I-rituximab (6000MBq/163mCi) combined with BEAM conditioning for autologous HSCT.
Short tandem repeat (STR) analysis is used in chimerism monitoring after allogeneic hematopoietic stem cell transplantation (HSCT) for patients with various hematologic malignancies. Commercial forensic STR kits often contain loci with huge differences in power of discrimination (PD) across populations, causing some loci to be less informative for chimerism analysis in certain populations. This study aimed to construct a new STR multiplex panel with highly informative loci for efficient chimerism analysis. Thirteen STR markers which exhibit high PD (> 0.9) in at least 80% of 50 populations globally were selected to form a new panel and used in STR analysis of 253 Malaysian subjects. Cumulative power of discrimination (CPD) and combined power of exclusion (CPE) were determined from 253 Malaysian individuals. Loci informativity was assessed and compared to the commercial AmpFLSTR Identifiler PCR Amplification kit in 14 donor-recipient pairs. The new panel had detected 202 unique alleles including five novel alleles from the 253 individuals with high CPD and CPE (> 0.99999999999999999 and > 0.999999997 respectively). All loci from the new panel in the donor-recipient pair analysis showed higher than 50% informativity, while five loci from the commercial kit demonstrated lower than 50% informativity. Four loci from the new panel ranked the highest informativity. A sequenced allelic ladder which consists of 202 unique alleles from the 253 subjects was also developed to ensure accurate allele designation. The new 13-loci STR panel, thus, could serve as an additional powerful, accurate, and highly informative panel for chimerism analysis for HSCT patients.
Peripheral blood stem cells (PBSC) mobilised with growth factor with or without chemotherapeutic regimens, are used increasingly in both autologous and allogeneic transplantation. Previously, many PBSC harvests are used directly without ex vivo manipulation, and these PBSC have been shown to be contaminated with tumour cells, which may contribute to subsequent relapses post transplantation. Therefore, requirement for purging of malignant cells from the harvest has initiated the use of various methods to reduce tumour cell contamination of the graft by the positive selection of CD34+ progenitor cells or negative selection of tumour cells using other cell-specific antigens. We report here our local experience with the CliniMACS (magnetic-activated cell separation system) in eight adult patients with haematologic malignancies.
Stem cell transplantation is a generic term covering different techniques. However there is argument over the pros and cons of autologous and allogeneic transplants of mesenchymal stem cells (MSCs) for regenerative therapy. Given that the MSCs have already been proven to be safe in patients, we hypothesize that allogeneic transplantation could be more effective and cost-effective as compared to autologous transplantation specifically in older subjects who are the likely victims of degenerative diseases. This analysis is based on the scientific logic that allogeneic stem cells extracted in large numbers from young and healthy donors could be physiologically, metabolically and genetically more stable. Therefore stem cells from young donors may be expected to exhibit higher vigor in secreting trophic factors leading to activation of host tissue-specific stem cells and also be more efficient in remodeling the micro-environmental niche of damaged tissue.
The incidence of Non-Hodgkin's lymphomas (NHL) is rising worldwide and if not adequately treated carries a high mortality rate. The pattern and frequency of NHL vary in different populations and geographical regions. It has considerable biologic and clinical heterogeneity and a definitive diagnosis can be made only after histopathogical examination. The histology and the extent of the lymphoma are the major determinants of optimal therapeutic regimen and treatment outcome. Additionally, the overall treatment strategies should be tailored according to medical status and preference of the patient. A holistic approach provided by a multi-disciplinary team of health care professionals is the cornerstone of ensuring successful treatment outcome. Importantly, therapy should be expedited and where possible performed in experienced centers. Patients achieving remission would require long-term monitoring for disease recurrence and late effects of cytotoxic chemotherapy and radiotherapy. Hence, clinicians should have a fundamental understanding in the biology and the principles of treatment of NHL. This review provides an evidence-based and systematic approach in designing therapeutic strategies for individual patients with newly diagnosed and relapsed NHL focusing on the common types of NHL with particular reference to the current practice within the local settings. The role of standard and novel therapeutic modalities in treatment will be summarized.
Introduction: During the last three decades hematopoietic stem cell transplantation (HSCT) has become a well-established treatment for many hematologic malignancies. The most important limitation for HSC transplantation is the low number of hematopoietic stem cells (HSC) that can lead to delayed engraftment or graft failures. Numerous attempts have been made to improve in vitro HSC expansion via optimization of various methods such as isolation techniques, supplementing with growth factors, utilizing stromal cells as feeder layer and other culture conditions. Objective: This project is aimed to decipher the efficiency of an isolation technique and retrieval of culture expanded HSC from feeder layer using two different harvesting methods. Materials and Methods: Hematopoietic stem cells from human umbilical cord blood were isolated via MACS mediated CD34+ double sorting. Then, the cells were cultured onto MSC feeder layer for 3 and 5 days. Culture expanded cells were harvested using two different harvesting method namely cell aspiration and trypsinization methods. Hematopoietic stem cell expansion index were calculated based on harvesting methods for each time point. Results: The numbers of HSC isolated from human umbilical cord blood were 1.64 x 106 and 1.20 x106 cells at single and double sortings respectively. Although the number of sorted cells diminished at the second sorting yet the yield of CD34+ purity has increased from 43.73% at single sorting to 81.40% at double sorting. Employing the trypsinization method, the HSC harvested from feeder layer showed a significant increase in expansion index (EI) as compared to the cell aspiration harvesting method (p≤ 0.05). However, the purity of CD34+ HSC was found higher when the cells were harvested using aspiration method (82.43%) as compared to the trypsinization method (74.13%). Conclusion: A pure population of CD34+ HSC can be retrieved when the cells were double sorted using MACS and expanded in culture after being harvested using cell aspiration method.
Multiple sclerosis is a debilitating disease of the central nervous system. It affects people of all ages but is more prevalent among 20-40 year olds. Patients with MS can be presented with potentially any neurological symptom depending on the location of the lesion. A quarter of patients with MS suffer from bilateral lower limb spasticity among other symptoms. These devastating effects can be detrimental to the patient's quality of life. Hematopoietic stem cells (HSCs) have been used as a treatment for MS over the past 2 decades but their safety and efficacy has are undetermined. The objective of this study is to evaluate the feasibility and toxicity of autologous HSCs transplantation in MS. A literature search was done from 1997 to 2016 using different keywords. A total of 9 articles, which met the inclusion and exclusion criteria, were included in this review. The type of conditioning regimen and technique of stem cell mobilization are summarized and compared in this study. All studies reported high-dose immunosuppressive therapy with autologous HSCs transplantation being an effective treatment option for severe cases of multiple sclerosis. Fever, sepsis, and immunosuppression side effects were the most observed adverse effects that were reported in the selected studies. HSCs is a feasible treatment for patients with MS; nevertheless the safety is still a concern due to chemo toxicity.
Between 2005 and 2015, 138,165 hematopoietic stem cell transplantation (HSCT) were reported in 18 countries/regions in the Asia-Pacific region. In this report, we describe current trends in HSCT throughout the Asia-Pacific region and differences among nations in this region and various global registries. Since 2008, more than 10,000 HSCTs have been recorded each year by the Asia-Pacific Blood and Marrow Transplantation Group Data Center. Between 2005 and 2015, the greatest increase in the number of HSCTs was observed in Vietnam. Allogeneic HSCT was performed more frequently than autologous HSCT, and a majority of cases involved related donors. Regarding allogeneic HSCT, the use of cord blood has remained steady, especially in Japan, and the number of cases involving related HLA non-identical donors has increased rapidly, particularly in China. The incidence of hemoglobinopathy, a main indication for allogeneic HSCT in India, China, Iran, and Pakistan, increased nearly six-fold over the last decade. Among the 18 participating countries/regions, the transplant rate per population varied widely according to the absolute number of HSCTs and the national/regional population size. We believe that this report will not only benefit the AP region but will also provide information about HSCT to other regions worldwide.
Studies of survival outcomes in acute myeloid leukemia (AML) patients treated with allogeneic haematopoietic stem cell transplantation (HSCT) are essential for planning patient care. The objectives of the present study were to determine overall survival (OS) and disease-free survival (DFS) in AML patients treated with allogeneic HSCT, and to identify prognostic factors associated with poor outcome. This study was conducted retrospectively, using data from the Blood and Bone Marrow Transplant, National Transplant Registry, Malaysia. All cases of AML treated with allogeneic HSCT registered at the registry between 1st January 1987 and 31st December 2010 were included in the study. A total of 300 patients were included for final analysis. The Kaplan-Meier method and Cox proportional hazard regression were used for statistical analysis. The overall 10-year OS and DFS for Malaysian AML patients after allogeneic HSCT were 63 and 67 %, respectively. Donor gender, marrow status, and conditioning intensity were identified as important prognostic factors for overall survival, whereas the significant prognostic factors for disease-free survival were ethnic group, donor gender, marrow status, and conditioning intensity. In conclusion, the survival outcomes for Malaysian AML patients treated with allogeneic HSCT were good, and this treatment should be considered the standard therapeutic approach for suitable candidates.
Currently, the indications to perform reduced-intensity conditioning allogeneic hematopoietic stem cell transplant (RIC-HCT) are based on data derived mainly from large registry and single-centre retrospective studies. Thus, at the present time, there is limited direct evidence supporting the current practice in selecting patients with acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL) for RIC versus myeloablative conditioning (MAC) transplants. To determine the relationship between dose intensity of conditioning regimen and survival outcomes after allografting in AML/ALL patients, we performed a meta-analysis of 23 clinical trials reported between 1990 and 2013 involving 15,258 adult patients that compare survival outcomes after RIC-HCT versus MAC-HCT. RIC-HCT resulted in comparable <2-year and 2-6 year overall survival (OS) rates post-transplantation even though the RIC-HCT recipients were older and had more active disease than MAC-HCT recipients. The 2-6 year progression-free survival (PFS), nonrelapse mortality, acute graft-versus-host disease (GvHD) and chronic GvHD rates were reduced after RIC-HCT, but relapse rate was increased. Similar outcomes were observed regardless of disease type and status at transplantation. Odds ratio for all outcomes remained comparable with or without performing separate analyses for the year of HCT and for retrospective versus prospective studies. Among RIC-HCT recipients, survival rates were superior if patients were in CR at transplantation. Significant inter-study heterogeneity for aGvHD data and publication bias for PFS data were observed. This meta-analysis showed no OS benefit of MAC-HCT over RIC-HCT across the entire cohort of patients suggesting that RIC-HCT could be an effective therapeutic option for AML/ALL patients who are ineligible for MAC-HCT and CR status is preferred before RIC-HCT.