Explore the vast range of titles available.

The Wiskott-Aldrich syndrome protein (WASP; encoded by the gene WAS ) and its homologs are important regulators of the actin cytoskeleton, mediating communication between Rho-family GTPases and the actin nucleation/crosslinking factor, the Arp2/3 complex 1 . Many WAS mutations impair cytoskeletal control in hematopoietic tissues, resulting in functional and developmental defects that define the X-linked Wiskott-Aldrich syndrome (WAS) and the related X-linked thrombocytopenia 2 (XLT). These diseases seem to result from reduced WASP signaling, often through decreased transcription or translation of the gene 3 , 4 , 5 , 6 , 7 , 8 . Here we describe a new disease, X-linked severe congenital neutropenia (XLN), caused by a novel L270P mutation in the region of WAS encoding the conserved GTPase binding domain (GBD). In vitro , the mutant protein is constitutively activated through disruption of an autoinhibitory domain in the wild-type protein, indicating that loss of WASP autoinhibition is a key event in XLN. Our findings highlight the importance of precise regulation of WASP in hematopoietic development and function, as impairment versus enhancement of its activity give rise to distinct spectra of cellular defects and clinical phenotypes.

Clinical resistance to chemotherapy in acute myeloid leukemia (AML) is associated with the expression of the multidrug resistance (MDR) proteins P-glycoprotein, encoded by the MDR1/ABCB1 gene, multidrug resistant-related protein (MRP/ABCC1), the lung resistance-related protein (LRP), or major vault protein (MVP), and the breast cancer resistance protein (BCRP/ABCG2). The clinical value of MDR1, MRP1, LRP/MVP, and BCRP messenger RNA (mRNA) expression was prospectively studied in 154 newly diagnosed AML patients >or=60 years who were treated in a multicenter, randomized phase 3 trial. Expression of MDR1 and BCRP showed a negative whereas MRP1 and LRP showed a positive correlation with high white blood cell count (respectively, p < 0.05, p < 0.001, p < 0.001 and p < 0.001). Higher BCRP mRNA was associated with secondary AML (p < 0.05). MDR1 and BCRP mRNA were highly significantly associated (p < 0.001), as were MRP1 and LRP mRNA (p < 0.001) expression. Univariate regression analyses revealed that CD34 expression, increasing MDR1 mRNA as well as MDR1/BCRP coexpression, were associated with a lower complete response (CR) rate and with worse event-free survival and overall survival. When adjusted for other prognostic actors, only CD34-related MDR1/BCRP coexpression remained significantly associated with a lower CR rate (p = 0.03), thereby identifying a clinically resistant subgroup of elderly AML patients.

Despite the revolutionary change in the prognosis of chronic myeloid leukemia (CML) patients with the introduction of imatinib, patients with resistant disease still pose a considerable problem. In this multicenter, randomized phase III trial, we investigate whether the combination of high-dose imatinib and intermediate-dose cytarabine compared to high-dose imatinib alone, improves the rate of major molecular response (MMR) in newly diagnosed CML patients. This study was closed prematurely because of declining inclusion due to the introduction of second generation tyrosine kinase inhibitors and only one third of the initially required patients were accrued. One hundred nine patients aged 18–65 years were randomly assigned to either imatinib 800 mg ( n  = 55) or to imatinib 800 mg in combination with two successive cycles of cytarabine 200 mg/m 2 for 7 days ( n  = 54). After a median follow-up of 41 months, 67 % of patients were still on protocol treatment. The MMR rate at 12 months was 56 % in the imatinib arm and 48 % in the combination arm ( p  = 0.39). Progression-free survival was 96 % after 1 year and 89 % after 4 years. Four-year overall survival was 97 %. Adverse events grades 3 and 4 were more common in the combination arm. The addition of intermediate-dose of cytarabine to imatinib did not improve the MMR rate at 12 months. However, the underpowering of the study precludes any definitive conclusions. This trial is registered at www.trialregister.nl (NTR674).

A 61-year-old eutrophic male was diagnosed with vitamin B12 deficiency and megaloblastic anemia. A modified Schilling test suggested intestinal malabsorption unrelated to intrinsic factor deficiency. Subsequent colonoscopy revealed the presence of a Taenia tapeworm. The anemia resolved within days under therapy with niclosamide and temporary vitamin B12 supplements. The present case suggests that, in addition to other well-known parasitic agents, e.g., Diphyllobothrium latum and Giardia lamblia, Taenia infestation can also be a cause of intestinal vitamin B12 malabsorption.

Graft-versus-host disease (GVHD) remains a major immunological complication after allogeneic bone marrow transplantation (allo-BMT), but also favors development of the beneficial graft-versus-leukemia (GVL) effect. A patient with AML-M4 (inv (16)) is described, who was given non-myeloablative remission reinduction therapy for leukemic relapse (inv (16), trisomy 8) diagnosed on day 184 after HLA-compatible sibling BMT. On day 236, ie about 6 weeks after completion of this course, a clinical syndrome suggestive of acute GVHD grade 3 had developed. Skin biopsy confirmed the clinical diagnosis of GVHD, with a compatible liver biopsy. Transfusion-associated GVHD was ruled out by analysis of short tandem repeat (STR) alleles in the skin biopsy, revealing alleles from donor and recipient but not from third party origin. Cyclosporin A (CsA) therapy, which had been tapered between days 150 and 175, was resumed, resulting in a favorable response and gradual transition to limited chronic GVHD. The patient has since remained in complete remission with an excellent performance status for more than 40 months, without further chemotherapy. Thus this biopsy proven case of GVHD was induced by marrow donor lymphocytes more than 200 days after transplantation and apparently triggered by remission reinduction chemotherapy. The case indicates that intensive non-myeloablative chemotherapy can cure AML relapsing after allo-BMT. The therapeutic effect in this case probably involved a direct pharmacological suppression of the leukemic clone followed by a GVL effect initiated by donor-derived alloreactive T lymphocytes.