Evolution of urticaria pigmentosa into indolent systemic mastocytosis: abnormal immunophenotype of mast cells without evidence of c-kit mutation ASP-816-VAL

Mastocytosis comprises a heterogeneous group of hematological disorders which are morphologically defined by proliferation and accumulation of tissue mast cells in one or more organs. Clinical manifestations of mastocytosis range from disseminated maculopapular skin lesions (= urticaria pigmentosa [UP]) that may spontaneously regress to highly aggressive neoplasms like mast cell leukemia or mast cell sarcoma. Recently, it could be shown that systemic mastocytosis (SM) is a clonal disorder often exhibiting mutations of c-kit, a protooncogene encoding the tyrosine kinase receptor for stem cell factor (SCF). Mutations of c-kit are considered to play a key role in the pathogenesis of mastocytosis. Therefore, we investigated the unique case of a 36 year-old male patient with indolent systemic mastocytosis (ISM) evolving from UP (cutaneous mastocytosis) by means of histology, immunophenotyping and molecular biology. At the time of initial diagnosis the bone marrow showed only a mild diffuse increase in mast cells but compact infiltrates were missing. The serum tryptase levels were normal. Five years later, however, the bone marrow histology displayed patchycompact mast cell infiltrates, which now allowed to establish the diagnosis of an ISM. The serum tryptase levels at this time were markedly elevated. At both time points, mast cells were analyzed by immunohistochemistry using anti-tryptase antibody AA1, by flow cytometry using antibodies against CD2 and CD25, and nested polymerase chain reaction (PCR) on laser-microdissected, single pooled mast cells. Immunohistochemistry revealed strong tryptase-positivity of mast cells in both cutaneous and bone marrow infiltrates. Flow cytometry yielded an aberrant expression of CD2 and CD25 on bone marrow mast cells. However, repeated thorough PCR analysis failed to unveil c-kit mutation in atypical mast cells of skin and bone marrow samples of both dates. These findings clearly show that ISM can evolve from UP. Moreover, our study provides further evidence that the c-kit mutation Asp-816-Val is not invariably present in ISM.     

Therapeutic embolisation for postoperative haemorrhage after total arthroplasty of the hip and knee

We describe three cases of postoperative haemorrhage, two after total hip and one after total knee replacement, treated by percutaneous embolisation. After diagnostic angiography, this is the preferred method for the treatment of postoperative haemorrhage due to the formation of a false aneurysm, after hip or knee arthroplasty. This procedure, carried out under local anaesthesia, has a low rate of complications and avoids the uncertainty of further surgical exploration.     

Characterization of (123)I-vascular endothelial growth factor-binding sites expressed on human tumour cells: possible implication for tumour scintigraphy

To explore the possibility of vascular endothelial growth factor (VEGF) receptor scintigraphy of primary tumours and their metastases, we analysed the binding properties of (123)I-labelled VEGF(165) ((123)I-VEGF(165)) and (123)I-VEGF(121) to human umbilical vein endothelial cells (HUVECs), several human tumour cell lines (HMC-1, A431, KU812, U937, HEP-1, HEP-G2, HEP-3B and Raji), a variety of primary human tumours (n = 40) and some adjacent non-neoplastic tissues as well as normal human peripheral blood cells in vitro. Two classes of high-affinity (123)I-VEGF(165)-binding site were found on the cell surface of HUVECs. In contrast, one class of high-affinity binding sites for (123)I-VEGF(165) was found on HMC-1, A431, HEP-1, HEP-G2, HEP-3B and U937 cells as well as many primary tumours. For (123)I-VEGF(121), a single class of high-affinity binding site was found on certain cell lines (HUVEC, HEP-1 and HMC-1) and distinct primary tumours (primary melanomas, ductal breast cancers and ovarian carcinomas as well as meningiomas). Tumour cells expressed significantly higher numbers of VEGF receptors compared with normal peripheral blood cells and adjacent non-neoplastic tissues. Immunohistochemical staining revealed that the VEGF receptor Flk-1 is expressed to a much higher extent within malignant tissues compared with neighbouring non-neoplastic cells. We observed significantly greater specific binding of (123)I-VEGF(165) and (123)I-VEGF(121) to a variety of human tumour cells/tissues compared with the corresponding normal tissues or normal peripheral blood cells. In comparison with (123)I-VEGF(121), (123)I-VEGF(165) bound to a higher number of different tumour cell types with a higher capacity. Thus, (123)I-VEGF(165) may be a potentially useful tracer for in vivo imaging of solid tumours.     

Utility of flow cytometric analysis of mast cells in the diagnosis and classification of adult mastocytosis

The diagnosis of bone marrow (BM) involvement in mastocytosis has mainly been based on conventional histology. Nevertheless, in recent years, three major methodological advances have been made: the measurement of serum tryptase levels, the immunohistochemical assessment of mast cell (MC) tryptase, and the immunophenotypical characterization of BMMC using flow cytometry (FCM). The most characteristic immunophenotypic feature in mastocytosis is the coexpression of CD2 and CD25 antigens, which are never present in normal BMMC and constitute a phenotypic hallmark of BMMC in adult mastocytosis. Such observations would support the need to include the immunophenotypic analysis of MC in the diagnosis of mastocytosis.     

Why clinicians should be interested in Interleukin-3

Summary Interleukin-3 (IL-3), a product of activated immune cells has recently been cloned and introduced in preclinical and clinical trials. The biological target-cell spectrum of IL-3 is broad and includes progenitor cells of various hematopoietic lineages as well as multiple stages of stem cell differentiation. IL-3 also induces growth of most primitive hemopoietic progenitors (CFU-blast). Synergistic effects on growth of myeloid cells (i.e. macrophages, eosinophils and blood basophils) are obtained by sequential use of IL-3 and later-acting myelopoietic cytokines. In addition, IL-3 supports terminal maturation, prolonges survival and enhances the functional properties of myeloid cells through high-affinity binding sites. In vivo administration of IL-3 is followed by an increase in peripheral white blood cell counts as well as by an increase in the number of circulating progenitor cells giving rise to mature hemopoietic cells in response to more lineage-restricted growth factors. IL-3 also regulates growth of leukemic cells and primes them to become more sensitive to cell cycle specific cytotoxic drugs. IL-3 apparently represents a novel and unique hemopoietic growth factor. Its clinical use should offer new strategies in the treatment of cytopenia, leukemic disease and in stem cell transplantation.     

A hybrid molecule resembling the epitope spectrum of grass pollen for allergy vaccination

BACKGROUND: Allergy vaccines based on natural allergen extracts contain greatly varying amounts of individual allergens with different immunogenicity. OBJECTIVE: To develop a novel type of allergy vaccine for complex allergen sources that combines defined amounts of the major allergens in the form of single hybrid molecules. METHODS: A hybrid molecule was engineered by PCR-based mending and expression of the cDNAs coding for the 4 major grass pollen allergens and compared with its single components by circular dichroism analysis, T-cell proliferation, ELISA competition, and histamine release assays. Immune responses to the hybrid molecule were studied in BALB/c mice and rat basophil leukemia assays. RESULTS: The hybrid contained most of the B-cell epitopes of grass pollen and could be used to diagnose allergy in 98% (n = 652) of patients allergic to grass pollen. Immunization of mice and rabbits with the hybrid induced stronger and earlier IgG antibody responses than equimolar mixtures of the components, which can be explained by the induction of stronger T-cell responses by the hybrid versus the individual components. IgG antibodies induced by vaccination with the hybrid blocked immediate allergic reactions, as demonstrated by rat basophil degranulation assays in a murine model of grass pollen allergy. CONCLUSION: We demonstrate for grass pollen allergy that recombinant hybrid molecules covering the spectrum of the disease-eliciting epitopes of complex allergen sources can be engineered.     

Hemodynamic effects of levosimendan compared with dobutamine in patients with low cardiac output after cardiac surgery

INTRODUCTION AND OBJECTIVES: Levosimendan is an inotropic agent that is effective in the treatment of heart failure. However, experience with levosimendan in patients with reduced cardiac output following cardiopulmonary bypass is limited. The objective of this study was to compare the short-term hemodynamic effects of levosimendan with those of dobutamine in managing low cardiac output after cardiac surgery. METHODS: Forty-one patients who had low cardiac output after cardiopulmonary bypass were randomly assigned to dobutamine (n=20), 24-hour infusion of 7.5 microg/kg per min, or levosimendan (n=21), at a loading dose of 12 microg/kg followed by 24-hour infusion of 0.2 microg/kg per min. The following parameters were determined during a 48-hour observation period: arterial, central venous, pulmonary arterial and pulmonary capillary wedge pressure, cardiac index, heart rate, stroke volume, and systemic and pulmonary vascular resistance. RESULTS: Although both dobutamine and levosimendan improved the cardiac index, the increase was significantly greater with levosimendan (2.4 [0.2] l/min per m2 vs 2.9 [0.3] l/min per m2, respectively, at 24 h; P<.05). Moreover, levosimendan significantly reduced systemic and pulmonary vascular resistance, and significantly decreased systemic arterial, pulmonary arterial, pulmonary capillary wedge, and central venous pressure. CONCLUSIONS: Both dobutamine and levosimendan are effective in managing postoperative low cardiac output. However, levosimendan induces non-specific systemic, venous and pulmonary vasodilation which can result in hypotension as a adverse event. In these patients, it is advisable to omit or reduce the loading dose.     

Immunotherapeutic effect of the lactobacillus vaccine, Solco Trichovac, in trichomoniasis is not mediated by antibodies cross reacting with Trichomonas vaginalis.

According to the producers of the lactobacillus vaccine, Solco Trichovac, its therapeutic effect in trichomoniasis is achieved by antibodies that are induced by the vaccination and cross react with Trichomonas vaginalis. Common antigens of Lactobacillus acidophilus from Solco Trichovac vaccine and T vaginalis were therefore sought by three different seroreactions. Immune serum against Lacidophilus obtained by vaccinating two healthy human volunteers and two rabbits with the original Solco Trichovac vaccine, as well as hyperimmune rabbit antiserum to T vaginalis, were tested with each of the two micro-organisms. No evidence of antigenic similarity between L acidophilus and T vaginalis was obtained with either serum in any of the three serological tests. A non-specific immunostimulatory effect therefore seems to be a more probable explanation of the mode of action of Solco Trichovac vaccine.     

Treatment responses to cladribine and dasatinib in rapidly progressing aggressive mastocytosis

Background Systemic mastocytosis (SM) is a mast cell neoplasm in which neoplastic cells usually display the D816V‐mutated variant of KIT. Cladribine (2CdA) and dasatinib are two drugs that counteract the in vitro growth of neoplastic mast cells in SM. However, only little is known about the in vivo effects of these drugs in SM. Patient and methods We report on a patient with highly aggressive interferon‐alpha‐resistant SM who was treated with 2CdA and dasatinib. In vitro pretesting revealed a response of neoplastic mast cells to both compounds with reasonable IC₅₀ values. Results The patient was treated with six cycles of 2CdA (0·13 mg kg^?1 intravenously daily on 5 consecutive days). Despite a short‐lived major clinical response and a decrease in serum tryptase, the patient progressed to mast cell leukaemia after the sixth cycle of 2CdA. The patient then received two further courses of 2CdA followed by treatment with dasatinib (100 mg per os daily). However, no major response was obtained and the patient died from disease progression after 2 months. Conclusions In a patient with rapidly progressing aggressive SM, neither 2CdA nor dasatinib produced a long‐lasting response in vivo, despite encouraging in vitro results. For such patients, alternative treatment strategies have to be developed.