Gene expression profiling in polycythemia vera using cDNA microarray technology.

Polycythemia vera (PV) is a myeloproliferative disorder characterized by an increased proliferation of all three myeloid lineages. The molecular pathogenesis of PV is unknown. Using cDNA microarrays comprising 6000 human genes, we studied the gene expression profile of granulocytes obtained from 11 PV patients compared with granulocytes obtained from healthy individuals. We found that 147 genes were up-regulated by >/==" BORDER="0">2.5 fold in the majority of PV patients. Eleven of these 147 genes were up-regulated in all PV patients studied and may represent a molecular signature for this disorder. An increase in the expression of several protease inhibitors with affinity for proteases that promote apoptosis in neutrophils (e.g., cystatin F, secretory leukocyte protease inhibitor), as well as the up-regulation of a number of antiapoptotic and survival factors was found (e.g., adrenomedullin, p38 mitogen-activated protein kinase). We speculate that the deregulation of these factors may inhibit normal apoptosis and promote cell survival in the granulocytes of patients with PV. These PV-specific expression changes are likely to be biologically important in the pathophysiology of this disorder.

Diagnostic and response assessment FDG PET-CT in neurolymphomatosis.

FDG PET-CT is a useful imaging tool in the diagnosis and response assessment of neurolymphomatosis, especially in cases of otherwise unexplained neuropathy following conventional diagnostic work-up including lumbar puncture, CT, and MRI. The use of a novel PET reconstruction algorithm improves image quality and lesion detection through increased signal-to-noise ratio.

A rare but potentially fatal cause of diarrhoea and weight loss: enteropathy-associated T-cell lymphoma.

Enteropathy-associated T-cell lymphoma (EATL) is a rare but potentially fatal cause of diarrhoea and weight loss. EATL commonly presents with abdominal pain, diarrhoea and weight loss, but can also present with complications such as bowel obstruction and perforation. It is a tumour of intraepithelial lymphocytes that occurs in a relatively young population. It is the most common neoplastic complication of coeliac disease, but can occur with no prior diagnosis of coeliac disease. This case demonstrates the difficulties that can be faced in diagnosing this disorder, particularly when there is no preceding history of coeliac disease. Early diagnosis is of utmost importance in order to start treatment before the effects of malnutrition increase the risk of complications from chemotherapy. Hence awareness of the condition among general medical physicians, to whom it will often present first, is essential. However, even with prompt diagnosis, outcomes for this condition remain poor.

Reversal of asymptomatic over-anticoagulation by orally administered vitamin K.

Over-anticoagulation with warfarin is common. There is good reason to reverse significantly high international normalised ratios (INRs), however, in practice, there is wide variation in the means to achieve this. Randomised controlled trials have provided evidence for using low dose orally administered phytomenadione for the reversal of asymptomatic over-anticoagulation. We devised an oral regimen using the intravenous preparation of phytomenadione (vitamin K1). Patients with an asymptomatic INR between 8.0 and 11.9 (n = 166) received 2.5 mg and those with an INR of 12.0-20.0 (n = 36) or >20 (n = 21) received 5 mg. Median INRs for the three groups of patients on day 1 (approximately 14 h) after vitamin K administration were 3.5, 3.0 and 2.9 respectively. In the patients given 2.5 mg, 77% had INRs between 2.0 and 4.9 on day 1. In the patients given 5 mg, 52% of those presenting with INRs of 12.0-20.0 returned between 2.0 and 4.9 1 d after administration of vitamin K. In the INR >20 group 44% returned with an INR between 2.0 and 4.9. Warfarin was reintroduced once the INR was <5 and the majority of patients remained stable for the following 14 d. This regimen for non-urgent correction is therefore effective and returns patients to a safe INR level without over-reversing anticoagulation.

Update on the clinical use and misuse of erythropoietin.

Anemia is a common finding in patients with hematologic malignancies and most commonly can be attributed to the anemia of chronic disease compounded by the myelotoxic effects of chemotherapy. Symptoms of anemia include fatigue, and the patient's quality of life may be impaired. Possible treatments for the anemia are to do nothing, to transfuse with red cells, or to treat with recombinant human erythropoietin (rhEPO). rhEPO has become standard treatment for the anemia in chronic renal failure and has been successfully used in anemia secondary to malignancy. In patients with lymphoproliferative diseases, rhEPO increases the hemoglobin concentration, decreases the need for transfusion, and improves the patients' quality of life. Disadvantages of rhEPO include its cost, efficacy in only around 60% of patients, and delay of 4 to 8 weeks before maximum benefit is achieved. The anemia in patients with myelodysplasia responds less well to rhEPO. Misuse of rhEPO is common in the clinical setting but usually not of clinical importance. Misuse to enhance sporting prowess is probably rare but has potentially serious consequences.

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

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.

Low expression of the putative tumour suppressor gene gravin in chronic myeloid leukaemia, myelodysplastic syndromes and acute myeloid leukaemia.

The putative tumour suppressor gene gravin is down-regulated in several solid tumours and is implicated in tumorigenesis. We have evaluated the expression levels of the gravin gene in the CD34(+)/blast cells of a range of myeloid malignancies as compared with controls using real-time quantitative polymerase chain reaction (PCR). Gravin was markedly down-regulated in 41 of 41 patients with acute myeloid leukaemia (AML), nine of 10 patients with myelodysplastic syndromes (MDS) and 33 of 33 patients with chronic myeloid leukaemia (CML), of whom 24 were in blast crisis (BC). We have shown that gravin is consistently down-regulated in the CD34(+)/blast cells of myeloid malignancies and may play a role in the molecular pathogenesis of these disorders.

GPVI levels in platelets: relationship to platelet function at high shear.

We have investigated the density of the collagen receptors glycoprotein VI (GPVI) and alpha 2 beta 1 on human platelets and their relationship to polymorphisms within the GPVI gene. GPVI levels varied 1.5-fold and showed a weak correlation (r = 0.35) with the levels of alpha 2 beta 1, which varied 3-fold. GPVI genotype had a significant effect on receptor levels with carriers of the proline 219 allele (approximately 22% of the population) having 10% lower GPVI levels than the more common serine homozygotes. GPVI and alpha 2 beta 1 levels were found to be significantly decreased on platelets from patients with myeloproliferative disorders (MPDs). In both the MPD and the control group, GPVI levels were found not to affect platelet function under high shear in whole blood. Similarly murine platelets that express up to 5-fold lower levels of GPVI showed no significant difference than controls in thrombus formation on a high-density collagen-coated surface. However platelets lacking the GPVI/Fc receptor gamma-chain (FcR gamma-chain) complex or a functional FcR gamma-chain (immunoreceptor tyrosine-based activation motif [ITAM] point mutant) exhibited severely abrogated thrombus formation at 800 s-1 and 1500 s-1. These results demonstrate that GPVI levels are tightly controlled and play a critical role in thrombus formation on collagen; nevertheless, a range of receptor densities can support platelet function under high shear.

Gene expression profiling in the myelodysplastic syndromes using cDNA microarray technology.

The myelodysplastic syndromes (MDS) comprise a heterogeneous group of clonal disorders of the haematopoietic stem cell and primarily involve cells of the myeloid lineage. Using cDNA microarrays comprising 6000 human genes, we studied the gene expression profiles in the neutrophils of 21 MDS patients, seven of which had the 5q- syndrome, and two acute myeloid leukaemia (AML) patients when compared with the neutrophils from pooled healthy controls. Data analysis showed a high level of heterogeneity of gene expression between MDS patients, most probably reflecting the underlying karyotypic and genetic heterogeneity. Nevertheless, several genes were commonly up or down-regulated in MDS. The most up-regulated genes included RAB20, ARG1, ZNF183 and ACPL. The RAB20 gene is a member of the Ras gene superfamily and ARG1 promotes cellular proliferation. The most down-regulated genes include COX2, CD18, FOS and IL7R. COX2 is anti-apoptotic and promotes cell survival. Many genes were identified that are differentially expressed in the different MDS subtypes and AML. A subset of genes was able to discriminate patients with the 5q- syndrome from patients with refractory anaemia and a normal karyotype. The microarray expression results for several genes were confirmed by real-time quantitative polymerase chain reaction. The MDS-specific expression changes identified are likely to be biologically important in the pathophysiology of this disorder.