Alexander Sternberg

Coexistence of LMPP-like and GMP-like Leukemia Stem Cells in Acute Myeloid Leukemia

The relationships between normal and leukemic stem/progenitor cells are unclear. We show that in ∼80% of primary human CD34+ acute myeloid leukemia (AML), two expanded populations with hemopoietic progenitor immunophenotype coexist in most patients. Both populations have leukemic stem cell (LSC) activity and are hierarchically ordered; one LSC population gives rise to the other. Global gene expression profiling shows the LSC populations are molecularly distinct and resemble normal progenitors but not stem cells. The more mature LSC population most closely mirrors normal granulocyte-macrophage progenitors (GMP) and the immature LSC population a previously uncharacterized progenitor functionally similar to lymphoid-primed multipotential progenitors (LMPPs). This suggests that in most cases primary CD34+ AML is a progenitor disease where LSCs acquire abnormal self-renewal potential.

Guidelines for the diagnosis and management of adult myelodysplastic syndromes.

Sally B. Killick, Chris Carter, Dominic Culligan, Christopher Dalley, Emma Das-Gupta, Mark Drummond, Helen Enright, Gail L. Jones, Jonathan Kell, Juliet Mills, Ghulam Mufti, Jane Parker, Kavita Raj, Alexander Sternberg, Paresh Vyas, David Bowen and British Committee for Standards in Haematology The Royal Bournemouth and Christchurch Hospitals NHS Foundation Trust, Bournemouth, Hull and East Yorkshire Hospitals NHS Trust, Hull, Aberdeen Royal Infirmary, Aberdeen, Sheffield Teaching Hospitals NHS Foundation Trust, Sheffield, Nottingham University Hospitals NHS Trust, Nottingham, Beatson West of Scotland Cancer Centre, Glasgow, UK, Tallaght Hospital Dublin, Trinity College Medical School, Dublin, Ireland, Newcastle Hospitals NHS Foundation Trust, Newcastle upon Tyne, University Hospital of Wales, Cardiff, Worcestershire Acute Hospitals NHS Trust and Birmingham NHS Foundation Trust, Birmingham, Kings College Hospital NHS Foundation Trust, London, Northampton General Hospital NHS Trust, Northampton, Guys and St Thomas’ and Kings College Hospitals NHS Foundation Trusts, London, Great Western Hospitals NHS Foundation Trust, Swindon, Oxford University and Oxford University Hospitals NHS Trust, Oxford, and St. James’s Institute of Oncology, Leeds Teaching Hospitals, Leeds, UK

C-terminal nucleophosmin mutations are uncommon in chronic myeloid disorders.

C‐terminal somatic mutations in nucleophosmin (NPM), a nucleolar shuttling protein that binds p53 and p19Arf, were recently described in karyotypically normal acute myeloid leukaemia (AML). We analysed primary marrow samples from 150 patients with various chronic myeloid disorders for mutations in the NPM1 gene encoding NPM. NPM1 mutations (tetranucleotide duplication) were detected in three patients, all of whom had chronic myelomonocytic leukaemia (CMML) and a short (<1 year) survival, with rapid progression to overt AML. All other patients were NPM1‐wild type in the region analysed. In conclusion, C‐terminal NPM mutations are uncommon in chronic myeloid neoplasia, but if present may represent an evolving leukaemic clone.

Neutropenia and anaemia associated with T-cell large granular lymphocyte leukaemia responds to fludarabine with minimal toxicity

Summary. T‐cell large granular lymphocyte leukaemia (T‐LGL) is a clonal disorder of T cells associated with neutropenia and anaemia. The clinical consequences are recurrent infections and transfusion dependence. The optimum treatment for severely affected patients remains to be defined. Current therapies require long‐term administration to maintain an effect. We report the reversal of severe neutropenia and/or anaemia in four patients treated with fludarabine which has been maintained since stopping treatment. The therapeutic side‐effects were restricted to one episode of fever not associated with neutropenia. We conclude that fludarabine is effective in T‐LGL, may be given safely despite severe neutropenia and induces durable treatment‐free remissions.

Defective nuclear localization of Hsp70 is associated with dyserythropoiesis and GATA-1 cleavage in myelodysplastic syndromes

Normal human erythroid cell maturation requests the transcription factor GATA-1 and a transient activation of caspase-3, with GATA-1 being protected from caspase-3-mediated cleavage by interaction with the chaperone heat shock protein 70 (Hsp70) in the nucleus. Erythroid cell dysplasia observed in early myelodysplastic syndromes (MDS) involves impairment of differentiation and excess of apoptosis with a burst of caspase activation. Analysis of gene expression in MDS erythroblasts obtained by ex vivo cultures demonstrates the down-regulation of a set of GATA-1 transcriptional target genes, including GYPA that encodes glycophorin A (GPA), and the up-regulation of members of the HSP70 family. GATA-1 protein expression is decreased in MDS erythroblasts, but restores in the presence of a pan-caspase inhibitor. Expression of a mutated GATA-1 that cannot be cleaved by caspase-3 rescues the transcription of GATA-1 targets, and the erythroid differentiation, but does not improve survival. Hsp70 fails to protect GATA-1 from caspases because the protein does not accumulate in the nucleus with active caspase-3. Expression of a nucleus-targeted mutant of Hsp70 protects GATA-1 and rescues MDS erythroid cell differentiation. Alteration of Hsp70 cytosolic-nuclear shuttling is a major feature of MDS that favors GATA-1 cleavage and differentiation impairment, but not apoptosis, in dysplastic erythroblasts.

Genetically distinct leukemic stem cells in human CD34- acute myeloid leukemia are arrested at a hemopoietic precursor-like stage.

Quek and colleagues identify human leukemic stem cells (LSCs) present in CD34− AML. In-depth characterization of the functional and clonal aspects of CD34− LSCs indicates that most are similar to myeloid precursors.

Reduced CD38 expression on CD34+ cells as a diagnostic test in myelodysplastic syndromes

This report indicates that a reduced mean fluorescence intensity of CD38 expression on CD34+ cells can be used as a surrogate marker for abnormalities in the CD34+ compartment of patients with myelodysplastic syndrome. See related perspective article on page 1041. Diagnosis of myelodysplastic syndrome can be difficult especially in cases with a low blast count and a normal karyotype. Flow cytometry has been used to distinguish myelodysplastic syndrome from non-clonal cytopenias. No one single simple flow cytometric parameter has been proposed to be diagnostic of myelodysplastic syndrome. We have studied samples from 100 myelodysplastic syndrome patients and as control samples; 70 non-clonal cytopenias, 5 subjects with normal hematology, 31 patients with acute myeloid leukemia and 11 with chronic myelomonocytic leukemia or myeloproliferative disorder. We show that reduced relative mean fluorescence of CD38 below a threshold value on CD34+ cells diagnosed low-grade myelodysplastic syndrome with 95% sensitivity (95% confidence interval, 87–99%) and 92% specificity (95% confidence interval, 82–97%). This simple flow cytometric test may be of value in the routine clinical diagnosis of myelodysplastic syndrome, especially in cases with a low blast count and normal karyotype.

Strontium‐89: a novel treatment for a case of osteosclerotic myeloma associated with life‐threatening neuropathy

Summary. Osteosclerotic myeloma is a rare disorder characterized by paraproteinaemia and osteosclerosis, and may be associated with a progressive peripheral neuropathy. Patients with widespread osteosclerotic lesions can succumb from neurological complications despite systemic chemotherapy. We present a case of disseminated osteosclerotic myeloma associated with POEMS (peripheral neuropathy, organomegaly, endocrinopathy, M band, skin changes) syndrome, which was complicated by a rapidly progressive, life‐threatening neuropathy. The patients symptoms remained unchanged in the face of combination chemotherapy. However, a substantial improvement was seen following outpatient treatment with the commonly available radioisotope strontium 89 in combination with steroids.

Cerebrospinal fluid penetrance of lenalidomide in meningeal myeloma

Loreal, O. (2011) Iron disorders of genetic origin: a changing world. Trends in Molecular Medicine, 17, 707–713. Dubljevic, V., Sali, A. & Goding, J.W. (1999) A conserved RGD (Arg-Gly-Asp) motif in the transferrin receptor is required for binding to transferrin. The Biochemical Journal, 341 (Pt 1), 11–14. Gao, J., Chen, J., De Domenico, I., Koeller, D.M., Harding, C.O., Fleming, R.E., Koeberl, D.D. & Enns, C.A. (2010) Hepatocyte-targeted HFE and TFR2 control hepcidin expression in mice. Blood, 115, 3374–3381. Jouanolle, A.M., Gandon, G., Jezequel, P., Blayau, M., Campion, M.L., Yaouanq, J., Mosser, J., Fergelot, P., Chauvel, B., Bouric, P., Carn, G., Andrieux, N., Gicquel, I., Le Gall, J.Y. & David, V. (1996) Haemochromatosis and HLA-H. Nature Genetics, 14, 251–252. Le Lan, C., Mosser, A., Ropert, M., Detivaud, L., Loustaud-Ratti, V., Vital-Durand, D., Roget, L., Bardou-Jacquet, E., Turlin, B., David, V., Loreal, O., Deugnier, Y., Brissot, P. & Jouanolle, A.M. (2011) Sex and acquired cofactors determine phenotypes of ferroportin disease. Gastroenterology, 140, 1199–1207.e1191–1192. Lee, P.L. & Barton, J.C. (2006) Hemochromatosis and severe iron overload associated with compound heterozygosity for TFR2 R455Q and two novel mutations TFR2 R396X and G792R. Acta Haematologica, 115, 102–105. Wallace, D.F., Summerville, L., Lusby, P.E. & Subramaniam, V.N. (2005) First phenotypic description of transferrin receptor 2 knockout mouse, and the role of hepcidin. Gut, 54, 980–986.