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Large-volume leukapheresis (LVL) differs from normal-volume leukapheresis (NVL) by increased blood flow and altered anticoagulation regimen. LVL is now regarded as a safe procedure for collection of peripheral blood progenitor cells (PBPCs), but it is not known whether the procedure will alter CD34+ cell quality or will be useful for patients who mobilize few CD34+ cells into peripheral blood.The results from 82 LVL and 125 NVL (4.0-5.3 and 2.7-3.5 times the patients’ blood volumes processed, respectively) were retrospec-tively analyzed in altogether 112 consecutive patients with malignant diseases.The LVL yielded significantly more CD34+ cells (4.2 × 106 vs. 3.1 × 106/kg, p = 0.006, all patients; and 1.8 × 106 vs. 1.3 × 106/kg, p = 0.004, bad mobilizers) and significantly higher colony-forming units (77 × 104 vs. 33 × 104/kg; all patients and 33 × 104 vs. 20 × 104/kg, p < 0.001, both groups). Significantly fewer leukapheresis procedures were required to obtain 2 × 106 CD34+ cells per kg (one vs. two, p = 0.001, all patients; and two vs. three, p = 0.009, bad mobilizers). No significant differences in CD34+ cell viability and time to hematologic recovery were observed between the patients who received PBPCs harvested by NVL and LVL.Although a median platelet loss of 36 percent can be expected, LVL can be recommended as the standard apheresis method for PBPC collections in patients with malignant diseases. LVL is particularly useful in patients who mobilize a low number of CD34+ cells into the peripheral blood. [ABSTRACT FROM AUTHOR]

Heat shock protein (HSP) 70 and HSP90 are released by primary human acute myeloid leukemia (AML) cells during stress-induced spontaneous in vitro apoptosis. The AML cells also show constitutive release of several cytokines and the systemic serum levels of several soluble mediators are altered in patients with untreated AML. In the present study, we have investigated serum levels of HSP70/HSP90 and the serum cytokine profiles of patients with untreated AML and patients receiving AML-stabilizing palliative treatment based on all-trans retinoic acid (ATRA) plus valproic acid. Patients with untreated AML showed increased HSP90 levels and a distinct serum cytokine profile when compared with healthy controls, and low pre-therapy HSP90 levels were associated with a prolonged survival during treatment with ATRA + valproic acid + theophyllin. Hierarchical cluster analysis showed a close association between HSP70, HSP90, IL-1 receptor antagonist (IL-1ra), and hepatocyte growth factor (HGF) levels. Furthermore, disease-stabilizing therapy altered the serum-cytokine profile, but the correlations between HSP70/HSP90/IL-1ra/HGF were maintained only when ATRA + valproic acid were combined with theophyllin but not when combined with cytarabine. We conclude that both HSP levels and serum cytokine profiles are altered and may represent possible therapeutic targets or prognostic markers in human AML., (Copyright © 2012 Wiley Periodicals, Inc.)

Heat shock proteins (HSPs) are molecular chaperones that assist proteins in their folding to native structures. HSPs are regarded as possible therapeutic targets in acute myeloid leukaemia (AML). We used bioinformatical approaches to characterize the HSP profile in AML cells from 75 consecutive patients, in addition to the effect of the HSP90 inhibitor 17-DMAG. Patients harbouring a FLT3-internal tandem duplication (FLT3-ITD) were extensively overrepresented in the cluster with high HSP levels, indicating a strong dependence of HSPs in stabilizing FLT3-ITD encoded oncoproteins. FLT3 ligation further increased the levels of HSP90 and its co-chaperone HSP70. HSP90 inhibition had a stronger pro-apoptotic effect for AML cells with FLT3-ITD than for cells with wild-type FLT3, whereas the anti-proliferative effect of HSP90 inhibition was similar for the two patient subsets. HSP90 inhibition altered the constitutive cytokine release profile in an anti-angiogenic direction independent of FLT3 mutational status: (i) pro-angiogenic CXCL8, MMP-2 and MMP-9 showed a stronger decrease than anti-angiogenic CXCL9-11, (ii) the Tie-2 agonist Ang-1 showed a stronger decrease than the potentially antagonistic Ang-2, and (iii) VEGF and HGF levels were decreased. Finally, HSP90 inhibition counteracted the leukaemia-stimulating effect of endothelial cells. Our studies demonstrate that HSP90 inhibition mediates anti-leukaemic effects through both direct and indirect activity., (© 2011 Blackwell Publishing Ltd.)

Proteasome inhibitors represent a new class of antineoplastic drugs that are considered in the treatment of haematological malignancies. We compared the effects of the reversible proteasome inhibitor bortezomib (Velcade) and the epoxomicin derivative PR-171, an irreversible inhibitor, on primary human acute myeloid leukaemia (AML) cells. Both drugs inhibited autocrine- and cytokine-dependent proliferation of primary AML blasts when tested at nanomolar levels (0.1-100 nmol/l). The antiproliferative effect was independent of basal chymotrypsin-like proteasome activity (showing a 20-fold variation between patients), genetic abnormalities, morphological differentiation and CD34 expression when testing a large group of consecutive patients (n = 54). The effect was retained in cocultures with bone marrow stromal cells. In addition, both drugs enhanced apoptosis. The effect of PR-171 could be detected at lower concentrations than for bortezomib, especially when testing the influence on clonogenic AML cell proliferation. Both drugs had divergent effects on AML cells' constitutive cytokine release. Furthermore, both drugs caused a decrease in proliferation and viability when tested in combination with idarubicin or cytarabine. An antiproliferative effect on primary human acute lymphoblastic leukaemia cells was also detected. We conclude that nanomolar levels of the proteasome inhibitors tested had dose-dependent antiproliferative and proapoptotic effects on primary AML cells in vitro.

Serum concentrations of E-selectin (CD62E), P-selectin (CD62P), ICAM-1 (CD54) and interleukin 6 were investigated in acute leukaemia patients with chemotherapy-induced leucopenia and complicating bacterial infections. Serum concentrations of both E-selectin and P-selectin were decreased in the leucopenic patients without infections when compared with levels before chemotherapy; and serum concentrations of both E-selectin and P-selectin showed a further decrease during complicating bacterial infections. In contrast to the leukaemia patients, previously healthy individuals with meningococcal disease showed markedly elevated serum concentrations of E-selectin and normal levels of P-selectin during infection. Serum concentrations of ICAM-1 and interleukin 6 increased during bacterial infections in the acute leukaemia patients with chemotherapy-induced leucopenia. The alterations in serum concentrations of soluble adhesion molecules and interleukin 6 reversed when clinical signs of bacterial infections resolved during antibiotic therapy. Our results demonstrate that acute leukaemia patients with chemotherapy-induced cytopenia show altered levels of both soluble adhesion molecules and interleukin 6 during complicating bacterial infections.