Christine Dosquet

Treatment of Polycythemia Vera With Hydroxyurea and Pipobroman: Final Results of a Randomized Trial Initiated in 1980

PURPOSE The overall impact of hydroxyurea (HU) or pipobroman treatments on the long-term outcome of patients with polycythemia vera (PV) has not been assessed in randomized studies. We report final analyses from the French Polycythemia Study Group (FPSG) study, which randomly assigned HU versus pipobroman as first-line therapy in 285 patients younger than age 65 years. PATIENTS AND METHODS The full methodology has been described previously. FPSG results were updated with a median follow-up of 16.3 years. Statistical analysis was performed by using competing risks on the intention-to-treat population and according to main treatment received. RESULTS Median survival was 17 years for the whole cohort, 20.3 years for the HU arm, and 15.4 years for the pipobroman arm (P = .008) and differed significantly from that in the general population. At 10, 15, and 20 years, cumulative incidence of acute myeloid leukemia/myelodysplastic syndrome (AML/MDS) was 6.6%, 16.5%, and 24% in the HU arm and 13%, 34%, and 52% in the pipobroman arm (P = .004). Cumulative myelofibrosis incidence at 10, 15, and 20 years according to main treatment received was 15%, 24%, and 32% with HU versus 5%, 10%, and 21% with pipobroman (P = .02). CONCLUSION Data from this unique randomized trial comparing HU with another cytoreductive drug in PV showed that (1) survival of patients with PV treated with conventional agents differed from survival in the general population, (2) evolution to AML/MDS is the first cause of death, (3) pipobroman is leukemogenic and is unsuitable for first-line therapy, and (4) incidence of evolution to AML/MDS with HU is higher than previously reported, although consideration should be given to the natural evolution of PV.

Randomized trial and local biological effect of autologous platelets used as adjuvant therapy for chronic venous leg ulcers.

OBJECTIVES Platelet products have been proposed as adjuvant therapy for wound healing. We undertook this study to determine the healing effect of topically applied frozen autologous platelets (FAP) on chronic venous ulcers, compared with effect of placebo, and whether use of topical FAP modifies local expression of vascular endothelial growth factor (VEGF), keratinocyte growth factor (KGF), interleukin 8 (IL-8), and tissue inhibitor of metalloproteinase-1 (TIMP-1) in wound fluid. METHODS This randomized, placebo-controlled, double-blind trial was carried out in institutional practice, with ambulatory patients with proved chronic venous leg ulcers. In all patients, whole venous blood was drawn for preparation of FAP. FAP or normal saline solution was applied three times per week for up to 12 weeks, together with hydrocolloids and standardized compression bandages. Leg ulcer surface was assessed with numerical pictures. IL-8, VEGF, KGF, and TIMP-1 levels were determined (enzyme-linked immunosorbent assay) in wound fluid after each 4 weeks of treatment. RESULTS Fifteen patients were randomized into two groups with comparable leg ulcer characteristics. Mean percent reduction in ulcer area was 26.2% in the FAP group versus 15.2% in the placebo group (P =.94). One ulcer in each group was completely healed at study end. Levels of TIMP-1 increased significantly during FAP treatment. IL-8 concentration was significantly lower in wound fluid of healing ulcers than in the fluid of nonhealing ulcers, in both FAP and placebo groups. Growth factor levels were not modified with FAP treatment. CONCLUSION Topical autologous platelets have no significant adjuvant effect on healing of chronic venous leg ulcers and increased wound fluid TIMP-1 concentration. Ulcer healing is associated with a decrease in wound fluid IL-8.

Age-related changes in human hematopoietic stem/progenitor cells

Adult stem cells are critical for maintaining cellular homeostasis throughout life, yet the effects of age on their regenerative capacity are poorly understood. All lymphoid and myeloid blood cell lineages are continuously generated from hematopoietic stem cells present in human bone marrow. With age, significant changes in the function and composition of mature blood cells are observed. In this study, we report that age‐related changes also occur in the human hematopoietic stem cell compartment. We find that the proportion of multipotent CD34+CD38− cells increases in the bone marrow of elderly (>70 years) individuals. CD34+CD38+CD90−CD45RA+/−CD10− and CD34+CD33+ myeloid progenitors persist at the same level in the bone marrow, while the frequency of early CD34+CD38+CD90−CD45RA+CD10+ and committed CD34+CD19+ B‐lymphoid progenitors decreases with age. In contrast to mice models of aging, transplantation experiments with immunodeficient NOD/SCID/IL‐2Rγ null (NSG) mice showed that the frequency of NSG repopulating cells does not change significantly with age, and there is a decrease in myeloid lineage reconstitution. An age‐related decrease in the capacity of CD34+ cells to generate myeloid cells was also seen in colony‐forming assays in vitro. Thus, with increasing age, human hematopoietic stem/progenitor cells undergo quantitative changes as well as functional modifications.

EMMPRIN promotes angiogenesis through hypoxia-inducible factor-2α–mediated regulation of soluble VEGF isoforms and their receptor VEGFR-2

Extracellular matrix metalloproteinase inducer (EMMPRIN/CD147) is thought to promote tumor angiogenesis mostly through its protease-inducing function and more recently by its ability to increase tumor cell expression of vascular endothelial growth factor (VEGF). In this study, we present evidence that EMMPRIN can promote angiogenesis by a direct effect on endothelial cells through a paracrine regulation of the VEGF/VEGF-receptor (VEGFR) system. Using human microvascular endothelial cell line-1 endothelial cells, we show that EMMPRIN selectively increased the soluble VEGF isoforms (121 and 165), but not the matrix-bound VEGF 189 form. In addition, EMMPRIN up-regulated the expression of VEGFR-2 without an effect on VEGFR-1. This increase in VEGFR-2 was responsible for the observed EMMPRIN stimulation of the migratory and tube formation capacity of endothelial cells. EMMPRINs effects, which were matrix metalloproteinase and urokinase-type plasminogen activator independent, were mediated primarily through hypoxia-inducible factor-2alpha expression, also up-regulated by EMMPRIN. VEGFR-2 increase was also observed in vivo in a mouse model of xenograph tumors overexpressing EMMPRIN. These results suggest that in addition to increasing protease production, EMMPRIN may contribute to the formation of a reactive stroma also through the up-regulation of hypoxia-inducible factor-2alpha, VEGFR-2, and the soluble forms of VEGF in endothelial cells, thus directly regulating the angiogenic process.

Tumour necrosis factor-α, interleukin-1β and interleukin-6 in patients with renal cell carcinoma

Abstract Patients with renal cell carcinoma (RCC) can exhibit fever, weight loss and increases in acute phase proteins. Interleukin (IL)-1, tumour necrosis factor (TNF) and IL-6 are considered major mediators of local and systemic inflammation. We measured plasma IL-1β, TNF-α (immunoradiometric assay) and IL-6 (ELISA) in 78 consecutive patients with untreated RCC and in 56 normal subjects. IL-6 plasma levels were higher in patients with RCC (mean 24.2 pg/ml, 11.1–37.3, 95% confidence interval) than in normal subjects (11.6 pg/ml, 10.1–13.1, n = 39, P 40 pg/ml) had a positive predictive value of 91.0% for lymph node and/or metastatic spread of RCC. IL-6 was statistically correlated with C-reactive protein (nephelometric assay) blood values (r′ = 0.67, n = 78, P

Cytokines and thrombosis.

Cytokines are pleiotropic mediators of inflammation and immunity. Leukocytes and vascular cells are both sources of cytokines and targets for them. Several cytokines affect key functions of vascular wall cells. Several clinical acute or chronic inflammatory situations associate modifications of the cytokine network and a pro-thrombotic state. Many experimental data support the hypothesis that endothelial cells have an active role in these situations. Endothelial cells activated by cytokines such as tumor necrosis factor and interleukin-1 have decreased antithrombotic or prothrombotic properties and express leukocyte adhesion molecules to a greater extent. Cytokines, chemokines, and colony stimulating factors modulate the recruitment and activation of leukocytes. Activated platelets aggregate and bind to endothelial cells and to immobilized leukocytes, thus causing vascular occlusion accompanied by coagulation and leading to thrombosis. Cytokine activation may be limited by natural inhibitors or by therapeutic agents such as monoclonal antibodies, recombinant proteins, and drugs that alter cytokine synthesis, which may be of benefit in infection, inflammation, and possibly atherosclerosis.

Clinical and molecular response to interferon-α therapy in essential thrombocythemia patients with CALR mutations

Myeloproliferative neoplasms are clonal disorders characterized by the presence of several gene mutations associated with particular hematologic parameters, clinical evolution, and prognosis. Few therapeutic options are available, among which interferon α (IFNα) presents interesting properties like the ability to induce hematologic responses (HRs) and molecular responses (MRs) in patients with JAK2 mutation. We report on the response to IFNα therapy in a cohort of 31 essential thrombocythemia (ET) patients with CALR mutations (mean follow-up of 11.8 years). HR was achieved in all patients. Median CALR mutant allelic burden (%CALR) significantly decreased from 41% at baseline to 26% after treatment, and 2 patients even achieved complete MR. In contrast, %CALR was not significantly modified in ET patients treated with hydroxyurea or aspirin only. Next-generation sequencing identified additional mutations in 6 patients (affecting TET2, ASXL1, IDH2, and TP53 genes). The presence of additional mutations was associated with poorer MR on CALR mutant clones, with only minor or no MRs in this subset of patients. Analysis of the evolution of the different variant allele frequencies showed that the mutated clones had a differential sensitivity to IFNα in a given patient, but no new mutation emerged during treatment. In all, this study shows that IFNα induces high rates of HRs and MRs in CALR-mutated ET, and that the presence of additional nondriver mutations may influence the MR to therapy.

Efficacy and safety of pegylated-interferon α-2a in myelofibrosis: a study by the FIM and GEM French cooperative groups.

Myeloproliferative neoplasm‐related myelofibrosis is associated with cytopenic or proliferative phases, splenomegaly and constitutional symptoms. Few effective treatments are available and small series suggested that interferon could be an option for myelofibrosis therapy. We performed a retrospective study of pegylated‐interferon α‐2a (Peg‐IFNα‐2a) therapy in myelofibrosis. Sixty‐two patients treated with Peg‐IFNα‐2a at 17 French and Belgian centres were included. Responses were determined based on the criteria established by the International Working Group for Myelofibrosis Research and Treatment. Mean follow‐up was 26 months. Sixteen of 25 anaemic patients (64%) (eight concomitantly receiving recombinant erythropoietin) achieved a complete response and transfusion‐independence was obtained in 5/13 patients (38·5%). Constitutional symptoms resolved in 82% of patients. All five leucopenic patients normalized their leucocyte counts, whereas a normal platelet count was obtained in 5/8 thrombocytopenic patients. Splenomegaly was reduced in 46·5% of patients, and complete resolution of thrombocytosis and leucocytosis were observed in 82·8% and 68·8% of patients, respectively. Side effects (mostly haematological) were mainly of grade 1–2. The only factor independently associated with treatment failure was a spleen enlargement of more than 6 cm below the costal margin. In conclusion, Peg‐IFNα‐2a induced high response rates with acceptable toxicity in a large proportion of patients with primary and secondary myelofibrosis, especially in early phases.

Arsenic trioxide is effective in the treatment of multiple myeloma in SCID mice.

Objectives : Pharmacological concentrations of arsenic trioxide (ATO) and organic arsenic melarsoprol induce apoptosis in malignant plasma cells. In an attempt to further document the interest of the arsenic in vivo, we treated severe combined immunodeficient (SCID) mice transplanted with human myeloma cells by ATO or melarsoprol.

Reduced EBF expression underlies loss of B-cell potential of hematopoietic progenitors with age.

Aging is accompanied by a reduction in the generation of B lymphocytes leading to impaired immune responses. In this study, we have investigated whether the decline in B lymphopoiesis is due to age‐related defects in the hematopoietic stem cell compartment. The ability of hematopoietic stem cells from old mice to generate B cells, as measured in vitro, is decreased 2–5‐fold, while myeloid potential remains unchanged. This age‐related decrease in B‐cell potential is more marked in common lymphoid progenitors (CLP) and was associated with reduced expression of the B‐lineage specifying factors, EBF and Pax5. Notably, retrovirus‐mediated expression of EBF complemented the age‐related loss of B‐cell potential in CLP isolated from old mice. Furthermore, transduction of CLP from old mice with a constitutively active form of STAT5 restored both EBF and Pax5 expression and increased B‐cell potential. These results are consistent with a mechanism, whereby reduced expression of EBF with age decreases the frequency with which multipotent hematopoietic progenitors commit to a B‐cell fate, without altering their potential to generate myeloid cells.