Allogeneic haematopoietic stem cell transplantation without a matched sibling donor: current options and future potential

<p><b>INTRODUCTION</b>Allogeneic haematopoietic stem cell transplantation (HSCT) has been used to treat a variety of malignant and non-malignant diseases. For patients who do not have a matched sibling donor or a optimally matched unrelated donor (MUD) for transplantation, other graft sources have been used, including mismatched haploidentical related donors and umbilical cord blood (CB).</p><p><b>MATERIALS AND METHODS</b>A literature review and comparison of HSCT with MUD, haploidentical donors and CB donors was performed. The relative value of MUD and CB donor recruitment was calculated based on search-hit ratios of respective registries.</p><p><b>RESULTS</b>The choice of haematopoietic stem cell (HSC) source for transplantation remains difficult, and is dependent on disease stage, the centre's experience, HLA-matching and cell dose. It remains a lengthy procedure to identify and procure HSC from an acceptably matched unrelated donor, which may lead to disease progression in some patients. In these cases, alternatives such as haploidentical transplants or CB transplants can offer a chance for timely treatment. Although results of haploidentical transplant have improved in some centres, this approach is less successful in many other centres embarking on this transplant technique. However, there is the prospect of availability of HSC donors for almost every patient if the challenges of haploidentical HSCT can be overcome. CB transplantation has been established as a valid alternative for patients who cannot identify a suitably matched unrelated donor quickly enough. Some centres even prefer CB as a HSC source to unrelated donor bone marrow (BM) for paediatric patients.</p><p><b>CONCLUSION</b>Further increases in the size and diversity of CB inventories may realise the potential of every patient having access to at least a 5/6 matched CB unit of adequate cell dose (70-fold relative value for each CB unit banked versus each BM donor recruited). Prospective comparisons of MUD, CB, and haploidentical HSCT are needed to validate the optimal HSC source for transplant in specific diseases.</p>

Use of phage display to isolate specific human monoclonal antibody fragments against a potential target for multiple myeloma

<p><b>INTRODUCTION</b>Multiple myeloma (MM), a malignancy of plasma cells, accounts for 10% of all haematological malignancies and is currently incurable. Although it can be treated, the disease tends to relapse after several years and becomes increasingly resistant to conventional therapy. Investigations into using humoral therapy for MM are now underway with a view that novel therapeutic agents may provide a more targeted therapy for MM.</p><p><b>MATERIALS AND METHODS</b>Here, phage display, a faster and more efficient method compared to classical hybridoma fusion technology, was used as a proof-of-concept to isolate several single-chain Fragment variables (scFv) against Ku86.</p><p><b>RESULTS</b>Anti-Ku86 polyclonal scFvs biopanning was successful where third round scFvs (A(450)~1.1) showed a 1/3 increase in binding as compared to the fi rst round scFvs (A(450)~0.4) with 100 microg/mL of antigen (purified human Ku86). Subsequent selection and verification of monoclonal antibodies using third round biopanning revealed 4 good affinity binding clones ranging from A(450)~0.1 to A450~0.15 on 12.5 microg/mL of antigen as compared to low binders (A(450)~0.07) and these antibodies bind to Ku86 in a specific and dose-dependent manner. Comparative studies were also performed with commercially available murine antibodies and results suggest that 2 of the clones may bind close to the following epitopes aa506-541 and aa1-374.</p><p><b>CONCLUSIONS</b>These studies using phage display provide an alternative and viable method to screen for antibodies quickly and results show that good affinity antibodies against Ku86 have been successfully isolated and they can be used for further studies on MM and form the basis for further development as anti-cancer therapeutic agents.</p>

Autologous haematopoietic stem cell transplantation for the treatment of multiple sclerosis

<p><b>INTRODUCTION</b>Autologous haematopoietic stem cell transplantation (auto-HSCT) has been performed for severe multiple sclerosis (MS) refractory to standard therapy with increasing frequency worldwide. However, experience in Asia employing this modality in MS has been limited. In this review, we explored the pathophysiology of autoimmunity and the underlying rationale for auto-HSCT in treating autoimmune diseases including MS, as well as existing published pre-clinical and clinical data. We aimed thereby to better understand the utility of treating MS with auto-HSCT and the feasibility of this procedure in Singapore.</p><p><b>METHODS</b>A Medline search was performed with the terms "haematopoietic stem cell transplantation", "multiple sclerosis" and "autoimmune diseases" from 1996 to 2005. Both original papers and review articles were considered.</p><p><b>MAIN FINDINGS</b>The majority of publications were from Europe or the United States and most clinical series from single centres had relatively small numbers of patients. Worldwide, the number of patients reported has been less than 300 since 1997. Existing data support the feasibility and promise of this procedure and ongoing Phase III trials may serve to confirm this initial experience.</p><p><b>CONCLUSION</b>Pre-clinical and early clinical data support the rationale for immunoablative therapy for autoimmune disorders. Auto-HSCT for severe MS is a feasible procedure and can be safely performed in centres with experience managing HSCT patients.</p>

Concurrent intermediate uveitis and an enhancing intracranial lesion as the initial manifestation of sarcoidosis

<p><b>INTRODUCTION</b>Posterior segment involvement has been described to be associated with central nervous system involvement in sarcoidosis as a result of direct sarcoid tissue infiltration or mass effect of a cerebral lesion. However, isolated intermediate uveitis occurring concurrently with central nervous system involvement prior to extensive systemic disease is rare.</p><p><b>CLINICAL PICTURE</b>We describe a patient with neuro-ophthalmic manifestations of intermediate uveitis and an enhancing basal ganglia lesion at initial presentation, in the absence of extensive systemic disease.</p><p><b>TREATMENT</b>He was treated with high-dose systemic steroids which was progressively tailed down over 6 months.</p><p><b>OUTCOME</b>There was prompt resolution of vitritis with good preservation of visual acuity.</p><p><b>CONCLUSION</b>The difficulties of the initial diagnosis of sarcoidosis and the indications for initiation of steroid therapy are illustrated. We use this case to emphasise the need for a high clinical suspicion of sarcoidosis in the presence of similar unusual and seemingly unrelated combinations of neurological manifestations so as to facilitate the prompt institution of appropriate treatment when indicated.</p>

Detection and quantification of the abelson tyrosine kinase domains of the BCR-ABL gene translocation in chronic myeloid leukaemia using genomic quantitative real-time polymerase chain reaction

<p><b>INTRODUCTION</b>Since undetectable BCR-ABL mRNA transcription does not always indicate eradication of the Ph+ CML clone and since transcriptionally silent Ph+ CML cells exist, quantitation by genomic PCR of bcr-abl genes can be clinically useful. Furthermore, hotspot mutations in the Abelson tyrosine kinase (ABLK) domain of the bcr-abl gene translocation in Philadelphia chromosome-positive (Ph+) chronic myeloid leukaemia (CML) cells confer resistance on the specific kinase blocking agent, STI571.</p><p><b>MATERIALS AND METHODS</b>Genomic DNA from K562, CESS and patient CML cells were amplified using rapid cycle quantitative real-time polymerase chain reaction for the gene regions spanning the mutation hotspots. In assays for ABLK exons 4 or 6, exonic or intronic PCR primers were used.</p><p><b>RESULTS</b>We show that separation of cycle threshold (CT) values for log-fold amplicon quantification was 2.9 cycles for ABLK exon 4, and 3.8 cycles for exon 6 with rapid amplification times. K562 CML cells were found to have a approximately 2 log-fold ABLK gene amplification. In contrast, patient CML cells had CT differences of 2.2 for both exon, suggesting that there was no significant ABLK gene amplification. DNA sequencing confirmed that neither K562 nor patient CML cells contained ABLK hotspot mutations. Messenger RNA transcription analysis permitted the assessment of BCR-ABL transcription, which was qualitatively correlated to genomic amplification.</p><p><b>CONCLUSIONS</b>This novel Q-PCR assay was found to have high fidelity and legitimacy, and potentially useful for monitoring minimal residual disease, transcriptionally silent Ph+ CML cells, and bcr-abl gene amplification.</p>