Profilins constitute a novel family of functional plant pan-allergens.

Type I allergy is a major health problem in industrialized countries where up to 15% of the population suffer from allergic symptoms (rhinitis, conjunctivitis, and asthma). Previously, we identified a cDNA clone that encoded a birch pollen allergen as profilin. Profilins constitute a ubiquitous family of proteins that control actin polymerization in eukaryotic cells; in particular, profilin participates in the acrosomal reaction of animal sperm cells. Although profilins had been unknown in plants so far, our finding led to the assumption that profilins might have similar functions in pollens during plant fertilization and therefore represent allergenic components in almost all pollens. We show that profilins are prominent allergens that can be isolated from tree pollens (Betula verrucosa, birch), from pollens of grasses (Phleum pratense, timothy grass), and weeds (Artemisia vulgaris, mugwort). About 20% of all pollen allergic patients tested (n = 65) displayed immunoglobulin E (IgE) reactivity to recombinant birch profilin that was expressed in pKK223-3. An IgE inhibition experiment performed with recombinant birch profilin and purified natural profilins from timothy grass and mugwort indicates common IgE epitopes. Moreover, all pollen profilins purified from these far distantly related plant species, and likewise the purified recombinant birch profilin, are able to elicit dose-dependent histamine release via high affinity Fc epsilon receptor of blood basophils from profilin allergic patients. The presence of profilin and possibly related proteins as crossreacting allergenic components in various plants therefore provides an explanation as to why certain allergic patients display type I allergic reactions with pollens and even food from distantly related plants. A functional pan-allergen, like profilin, available as purified recombinant protein, may be a useful diagnostic and probably therapeutic reagent.

Elevated tryptase levels selectively cluster in myeloid neoplasms: a novel diagnostic approach and screen marker in clinical haematology.

BACKGROUND: Recent data suggest that tryptase, a mast cell enzyme, is expressed in neoplastic cells in myeloid leukaemias. In several of these patients, increased serum tryptase levels are detectable. MATERIALS AND METHODS: We have determined serum tryptase levels in 914 patients with haematological malignancies, including myeloproliferative disorders (n = 156), myelodysplastic syndromes (MDS, n = 241), acute myeloid leukaemia (AML, n = 317), systemic mastocytosis (SM, n = 81), non-Hodgkin's lymphoma (n = 59) and acute lymphoblastic leukaemia (n = 26). Moreover, tryptase was measured in 136 patients with non-neoplastic haematological disorders, 102 with non-haematological disorders and 164 healthy subjects. RESULTS: In healthy subjects, the median serum tryptase was 5.2 ng mL(-1). Elevated serum tryptase levels were found to cluster in myeloid neoplasm, whereas almost all patients with lymphoid neoplasms exhibited normal tryptase. Among myeloid neoplasms, elevated tryptase levels (> 15 ng mL(-1)) were recorded in > 90% of patients with SM, 38% with AML, 34% with CML and 25% with MDS. The highest tryptase levels, often > 1000 ng mL(-1), were found in advanced SM and core-binding-factor leukaemias. In most patients with non-neoplastic haematological disorders and non-haematological disorders analysed in our study, tryptase levels were normal, the exception being a few patients with end-stage kidney disease and helminth infections, in whom a slightly elevated tryptase was found. CONCLUSIONS: In summary, tryptase is a new diagnostic marker of myeloid neoplasms and a useful test in clinical haematology.

Immunosuppression and atypical infections in CML patients treated with dasatinib at 140 mg daily.

BACKGROUND: The multikinase inhibitor dasatinib exerts growth-inhibitory effects in patients with imatinib-resistant chronic myeloid leukaemia (CML). In first clinical trials, side effects of dasatinib, 140 mg daily, were reported to be mild and tolerable. PATIENTS AND METHODS: We examined the side effect profile in 16 patients with imatinib-resistant CML who received 140 mg dasatinib daily in our center. RESULTS: Dasatinib produced substantial and sometimes severe or even life-threatening side effects with > or = 10% body weight loss (6/16 patients), pleural effusions grade II or higher (12/16) and infectious complications (12/16), including atypical infections not seen in imatinib-treated patients. One patient developed Epstein-Barr-Virus-positive mucosal leucoplakia, one died from pneumonia caused by pneumocystis carinii and three patients developed a skin-cancer. Most events were recorded within the first 2 years of therapy, only skin tumours developed after the second year. In ex vivo experiments performed in dasatinib-treated patients, transient suppression of IgE-dependent activation of blood basophils and TcR-dependent activation of T-lymphocytes was found. Moreover, in drug-binding studies, dasatinib was found to bind to several key kinase-targets of the immune system including Lyn and Btk, in mast cell, basophil, B-cell and T-cell lines. CONCLUSION: Dasatinib acts not only anti-neoplastic in CML but may also act as an immunosuppressive agent when applied at 140 mg daily, and produces frequent pleural effusions and weight loss in advanced CML.

Identification of profilin as a novel pollen allergen; IgE autoreactivity in sensitized individuals.

A complementary DNA encoding a pollen allergen from white birch (Betula verrucosa) that was isolated from a pollen complementary DNA library with serum immunoglobulin E from a birch pollen-allergic individual revealed significant sequence homology to profilins. The recombinant protein showed high affinity to poly-L-proline. Immunoglobulin E antibodies from allergic individuals bound to natural and recombinant birch profilin and also to human profilin. In addition, birch and human profilin induced histamine release from blood basophils of profilin-allergic individuals, but not of individuals sensitized to other plant allergens. The structural similarity of conserved proteins might therefore be responsible for maintaining immunoglobulin E antibody titers in type I allergy.

Evaluation of antileukaemic effects of rapamycin in patients with imatinib-resistant chronic myeloid leukaemia.

BACKGROUND: Recent data suggest that the mammalian target of rapamycin (mTOR) is involved in the regulation of growth of neoplastic cells in chronic myeloid leukaemia (CML). PATIENTS AND METHODS: We treated six patients with imatinib-resistant CML in haematological relapse (leukocytes > 20,000 microL(-1)) with rapamycin at 2 mg per os daily for 14 consecutive days, with dose-adjustment allowed to reach a target rapamycin serum concentration of 10-20 pg mL(-1). RESULTS: A major leukocyte response with decrease to less than 10,000 microL(-1) was obtained in two patients, and a minor transient response was seen in two other patients. In responding patients, we also observed a decrease in vascular endothelial growth factor (VEGF) mRNA levels in circulating leukaemic cells. Side effects during rapamycin treatment were mild in most patients. In one patient, pneumonia developed. Rapamycin was also found to counteract growth of CML cells in vitro as determined by (3)H-thymidine incorporation. Moreover, rapamycin inhibited the growth of Ba/F3 cells exhibiting various imatinib-resistant mutants of BCR/ABL, including the T315I variant that exhibits resistance against most currently available BCR/ABL kinase inhibitors. CONCLUSIONS: Rapamycin shows antileukaemic effects in imatinib-resistant CML in vitro and in vivo. Larger trials with rapamycin or rapamycin-derivatives in combination with other targeted drugs are warranted to further determine clinical efficacy in CML.

Clinical and prognostic significance of histamine monitoring in patients with CML during treatment with imatinib (STI571).

BACKGROUND: Although imatinib is highly effective in chronic myeloid leukemia (CML), drug-resistance may occur. Therefore, monitoring of minimal residual disease (MRD) during treatment with imatinib is important. However, most MRD-parameters are expensive and require special technology. We determined the value of histamine as MRD-marker in CML. PATIENTS AND METHODS: Histamine levels were measured serially in whole blood samples before and during imatinib therapy in 80 CML patients by radioimmunoassay. RESULTS: Histamine levels were highly upregulated in CML at diagnosis compared to healthy controls, and correlated with the presence of basophils. During treatment with imatinib, histamine levels decreased and returned to normal levels in those achieving a complete cytogenetic response (CCR). Loss of CCR during therapy was invariably accompanied by an increase in histamine. Moreover, a histamine level of >100 ng/ml three or six months after start of imatinib was associated with a significantly reduced probability of survival (p<0.05). Whereas basophils were found to correlate well with histamine during imatinib, no correlations were found between histamine and Ph+ metaphases or histamine and BCR/ABL. CONCLUSION: Histamine-monitoring during treatment with imatinib is of prognostic significance.

Mesenchymal stem cells in patients with chronic myelogenous leukaemia or bi-phenotypic Ph+ acute leukaemia are not related to the leukaemic clone.

BACKGROUND: Human mesenchymal stem cells (MSCs) are thought to be multipotent cells which primarily reside in the bone marrow. Besides their well-known ability to replicate as undifferentiated cells and to differentiate into diverse lineages of mesenchymal tissues, they were recently suggested to also give rise to haematopoietic and leukaemic/cancer stem cells. In this study, the relationship between MSCs and leukemic stem cells in patients with either chronic myelogenous leukaemia (CML) or the more primitive variant, Ph+ bi-phenotypic leukaemia was investigated. PATIENTS AND METHODS: Cultured MSCs from 5 patients with CML and 3 patients with bi-phenotypic Ph+ leukaemia, all of them positive for BCP-ABL, were analysed with conventional cytogenetics, fluorescence in situ hybridisation (FISH) and polymerase chain reaction (PCR) for the presence of t(9;22) and BCR-ABL. MSCs were characterised phenotypically with surface markers (+CD73, +CD90, +CD105, -CD34, -CD45) and functionally through their potential to differentiate into both adipocytes and osteoblasts. RESULTS: MSCs could be cultivated from seven patients. These cells were BCR-ABL negative when analysed with conventional cytogenetics and FISH. Further cytogenetic analysis revealed a normal set of chromosomes without any aberrations. Two patients were BCR-ABL-positive when analysed with PCR, probably as a result of MSC contamination with macrophages. CONCLUSION: MSCs in patients with CML or Ph+ bi-phenotypic leukaemia are not related to the malignant cell clone.

Alemtuzumab-BEAM as conditioning for allogeneic hematopoietic stem cell transplantation in relapsed/refractory Hodgkin lymphoma: a single-center analysis.

PURPOSE: Treatment of refractory Hodgkin disease deserves specific considerations. Recently, alemtuzumab-BEAM has been introduced in allogeneic hematopoietic stem cell transplantation (HSCT) in these patients. METHODS: We retrospectively analyzed the outcome of 20 patients with relapsed/refractory Hodgkin's lymphoma (HL) who received allogeneic HSCT following conditioning therapy with alemtuzumab-BEAM. RESULTS: Treatment-related toxicity was tolerable. Half of the patients (50 %) had infections. Of these, 50 % were found to have pneumonia or catheter-related infections. In 20 %, an oral mucositis was observed. Acute graft-versus-host disease (GvHD) (≥grade 2) was seen in three patients. Complete remission (CR) could be achieved in 17 patients (85 %), 2 patients had persistent Hodgkin disease, and 1 patient died from infection prior to CR evaluation. Median progression-free survival and overall survival were 17.9 and 67.5 months, respectively. From the 17 CR patients, 8 had a relapse after a median of 10 months. Notably, of the eight patients relapsing after HSCT, all patients received another salvage treatment and four patients are still alive, whereas the other four patients died due to further progress. Six out of the remaining nine patients are still in CR, whereas the other three died from chronic GvHD and multi-organ failure. Overall, seven patients experienced chronic GvHD. CONCLUSION: In summary, alemtuzumab-BEAM is a well-tolerated conditioning therapy for allogeneic HSCT with high response rates in refractory HL.

A case of malignant mastocytosis with circulating mast cell precursors: biologic and phenotypic characterization of the malignant clone.

The phenotypic and biologic properties of malignant cells in a case of aggressive mastocytosis with multi-organ involvement, circulating mast cell precursors and absence of skin infiltrates were analyzed. Circulating mast cell precursors were detected by immunostaining using antibodies against mast cell tryptase as well as by electron microscopy. These progenitors were tryptase+/chymase- (MCT) and accounted for 10 to 20% of nucleated mononuclear blood cells (MNC). A subset of them contained metachromatic granules. As assessed by combined toluidine blue/immunofluorescence staining, the granulated mast cell precursors were found to express CD9 (P24), CD33 (gp67) and CD44 (Pgp-1), but not basophil-related markers (CD11b (C3biR), CDw17 (lactosylceramide), CD123 (il-3R alpha))or monocyte-related antigens (CD14, CD15). Expression of the mast cell growth factor (MGF) receptor, c-kit(CD117), was also demonstrable, whereas the skin mast cell marker C5aR (CD88) could not be detected on mast cell precursors. The ligand of c-kit, recombinant human (rh) stem cell factor (SCF = MGF), induced histamine release from circulating mast cell progenitors, whereas rhC5a, a potent skin mast cell-/basophil-agonist, was ineffective over the dose-range (10(-9) to 10(-7(M)) tested. Analysis of mast cell antigens in malignant mastocytosis or mast cell leukemias may be helpful to establish a diagnosis and to determine the phenotype of the clone.

Prognostic significance of WT1 gene expression at diagnosis in adult de novo acute myeloid leukemia.

We examined the presence of WT1-specific mRNA in bone marrow samples of 125 patients with de novo acute myeloid leukemia at diagnosis by two-step RT-PCR. The sensitivity of the assay was 1:100 (first step) and 1:10000 (second step), respectively. WT1-specific mRNA was detected in 73% of patients. No correlation was found between WT1 gene expression and age, FAB type, LDH and karyotype at diagnosis. All patients were treated with standard induction chemotherapy. There was no difference in the CR rate between WT1-positive and -negative patients. Using Kaplan and Meier plot analysis we found no difference in disease-free survival (DFS) and overall survival (OS) between patients displaying the WT1 transcript and WT1-negative patients. Furthermore, no significant interactions between WT1 PCR results and age, FAB type, LDH and karyotype on DFS and OS were demonstrable using Cox regression analysis. Eight patients who were WT1 PCR positive at diagnosis and achieved complete hematological remission following chemotherapy were monitored during the course of the disease. Based on our limited data demonstrating a heterogeneity of WT1 PCR results in CR we cannot draw any conclusions regarding the usefulness of WT1 PCR analysis for the early detection of relapse. We conclude that WT1 gene expression at diagnosis is not associated with specific characteristics of AML blast cells and is not a prognostic factor for CR, remission duration and overall survival in acute myeloid leukemia.

Immunophenotypic and functional characterization of human tonsillar mast cells.

Mast cells (MC) are proinflammatory immune cells residing in various organs. Tissue-specific heterogeneity of MC has been described. The aim of this study was to establish the phenotype and functional profile of human tonsillar mast cells (ToMC) and to compare ToMC with lung-, skin-, and uterus MC. Tonsillar tissue was obtained from 23 patients suffering from hyperplastic tonsils and dispersed by enzymatic digestion. With the use of a combined toluidine blue/immunofluorescence staining technique, isolated ToMC were found to react with monoclonal antibodies (mAb) to immunoglobulin E, CD9, CD43, CD44, CD46, CD54, CD55, and CD59, as well as mAb to stem cell factor (SCF) receptor (CD117/c-kit). ToMC were not recognized by mAb to other cytokine receptors or mAb to CD3, CD11b, CD14, CDw17, the skin MC marker CD88 (C5aR) or CD89 (Fc alphaR). Activation of ToMC by recombinant human (rh) SCF or anti-IgE resulted in histamine secretion, whereas no effects were seen with rhC5a, rh granulocyte-macrophage colony-stimulating factor, or rh interleukin-1 through -10. In summary, ToMC exhibit functional and phenotypic properties similar to lung- or uterus MC. Unlike skin MC, ToMC lack C5aR and are unresponsive to rhC5a.

Tumor necrosis factor alpha and interleukin-1 beta mRNA expression in HMC-1 cells: differential regulation of gene product expression by recombinant interleukin-4.

Cytokine-activation pathways in mast cells are supposed to play a significant role in host defense mechanisms and allergic reactions. Interleukin-4 (IL-4) is a well-characterized regulator of growth and function of mast cells. The human mast cell line HMC-1 was established from a patient suffering from mast cell leukemia and was shown to expose IL-4 binding sites. In the present study, the effects of recombinant human (rh) IL-4 and other rh cytokines (IL-2, IL-3, IL-6, IL-8) on expression of cytokine mRNA in HMC-1 cells were examined by Northern blot analysis using oligonucleotide probes. Tumor necrosis factor alpha (TNF-alpha) and IL-1 beta transcripts were found to be expressed constitutively in HMC-1 cells, whereas transcripts for IL-3, IL-4, IL-5, IL-6, and granulocyte-macrophage colony-stimulating factor (GM-CSF) could not be detected. Of all cytokines tested, rhIL-4 was found to down-regulate IL-1 beta mRNA expression and formation of immunoreactive IL-1 beta protein in HMC-1 cells. The effect of IL-4 on IL-1 beta gene product expression was time- and dose-dependent (maximum effects obtained with 100 U/mL of rhIL-4). No effect of IL-4 on expression of TNF-alpha mRNA in HMC-1 cells was observed. These results raise the possibility that human mast cells are a source of both TNF-alpha and IL-1 beta. Furthermore, our study provides evidence that IL-4 regulates IL-1 beta gene product expression in HMC-1 cells. The HMC-1 cell line should be a useful tool for studying cytokine activation pathways in human mast cells.

Phenotypic characterization of human skin mast cells by combined staining with toluidine blue and CD antibodies.

Mast cells (MC) are important cellular components of the immune network in diverse organs. The skin MC has likewise been implicated in IgE- and complement-mediated cutaneous reactions. Such reactions supposedly involve specific cell surface membrane receptors. In this study, the cell surface marker profile of human skin MC was established using monoclonal antibodies (MoAb) against defined CD antigens. MC were isolated from juvenile foreskin (n = 55) and adult mammary skin (n = 5). The reactivity of MC with MoAb was assessed by a combined toluidine blue/immunofluorescence staining technique. Confirming our previous analyses on lung MC, foreskin MC reacted with MoAb against CD9, CD29, CD33, CD43, CD44, CD45, CD46, CD51, CD54, CD55, CD58, CD59, CD61, and CD117 (c-kit). Foreskin MC were also recognized by MoAb to CD47, CD48, CD49d, CD53, CD60, CD63, CD81, CD82, CD84, CD87, CD92, CD97, CD98, and CD99. Recently clustered CD antigens detectable on foreskin MC were CD147 (neurothelin), CD149 (MEM133), CD151 (PETA-3), and CD157 (BST-1). In contrast to lung MC and MC from adult skin, foreskin MC were found to express CD88 (C5aR). Also, cutaneous MC (from both juvenile foreskin and adult mammary skin), but not lung MC, were found to bind the CD32 MoAb IV.3, 2E1, and FLI8.26 (Fc gammaRII). The CD50 antigen (ICAM-3) was detectable on lung MC, but not on foreskin MC or MC of adult mammary skin. In summary, our data show that cutaneous MC and lung MC express an almost identical phenotype; however, in contrast to lung MC, cutaneous MC appear to express substantial amounts of CD32 and to lack CD50. In addition, foreskin MC, unlike MC from adult skin or lung, express CD88.

Diagnostic value of immunostaining for tryptase in patients with mastocytosis.

The term "mastocytosis" is used to describe a heterogeneous group of disorders characterized by abnormal growth and accumulation of mast cells (MCs). Cutaneous and systemic variants exist. Systemic mastocytosis may show an indolent or malignant clinical course. In malignant mastocytosis (MM), the diagnosis often is missed because the MCs are morphologically abnormal and lack metachromatic granules or the underlying histologic picture is complex. The cytoplasmic serine protease tryptase is produced by MCs and is thought to be expressed at all stages of MC maturation. To assess the diagnostic value of tryptase staining in mastocytosis, tissue sections from 93 patients with mastocytosis, including MM (n = 37), systemic indolent mastocytosis (n = 47), urticaria pigmentosa (n = 5), MC leukemia (n = 2), and solitary skin mastocytoma (n = 2) were stained with the antitryptase antibody G3. The results were compared with those of Giemsa and chloroacetate esterase (CAE) staining. Using antitryptase antibody G3, MC infiltrates were identified in all patients examined, including those with MM (37 of 37), and virtually all the neoplastic MCs (> 95%) appeared to react with G3. In MM, significantly fewer MCs were positive in Giemsa (54.5%; p < 0.05) and CAE (78.8%; p < 0.05). Moreover, G3 produced clear diagnostic staining in all cases of MM, but the proportion of cases with clear diagnostic results (> 10% of neoplastic cells positive) was considerably lower with Giemsa (48.6%; p < 0.05) and CAE (75.7%; p < 0.05) staining. By contrast, tryptase, Giemsa, and CAE produced diagnostic staining of MCs in virtually all cases of systemic indolent mastocytosis, urticaria pigmentosa, and solitary skin mastocytoma. In systemic mastocytosis, survival was significantly reduced in cases with Giemsa-/tryptase+ or CAE-/tryptase+ tumor cells compared to those cases with Giemsa+ or CAE+ MC infiltrates (p < 0.001).

New aspects in thrombosis research: possible role of mast cells as profibrinolytic and antithrombotic cells.

Venous thromboembolism represents a significant cause of morbidity worldwide. The factors that underly thrombophilia are manifold. The concept of Virchow defines the well known triad of stasis, humoral factors, and pathologies of the vascular wall. In the current article, an additional factor, the "accumulation of repair cells" is discussed. This novel concept highlights the mast cell that accumulates around thrombosed vessels and provides a number of important repair molecules including heparin, profibrinolytic tPA, and fibrinogenolytic beta-tryptase. Thus, mast cell recruitment and activation may result in local thrombolysis and prevention of coagulation. In line with this concept, mast cell-deficient mice are more susceptible to lethal thrombogenic stimuli compared to normal mice. The factors (cytokines) that trigger mast cell accumulation and release of repair molecules have also been identified - the most important one appears to be stem cell factor (SCF). All in all. our novel concept suggests that the patho-physiology of thrombosis may involve a "physiologic" cell that provides the same repair molecules that are used for treatment of thrombotic disorders by the physician. Whether an altered availability of components of this cellular repair system can predispose for thrombophilia remains to be determined.

Low dose thalidomide in patients with relapsed or refractory multiple myeloma.

Remarkable results of the treatment of refractory multiple myeloma with thalidomide have been reported. In most preceding studies, the given thalidomide dose was escalated to a maximum tolerated dose of up to 800 mg/d. The frequency of adverse effects correlates with dose intensity. Since a significant gain of therapeutic effects could not be observed as thalidomide dosage was escalated, the optimal dose of thalidomide remains to be determined. We report the results of a study with low dose thalidomide (median administered dose 100 mg/d, range 50-400 mg/d). Twenty-four relapsed (n = 19) or resistant (n = 5) multiple myeloma patients were included in the study. Twelve patients (50%) received thalidomide as monotherapy, 8 patients (33%) received a combination of thalidomide and dexamethasone (every 4 weeks 40 mg/day for 4 days) and 4 patients (17%) who were resistant to vincristine, doxorubicin, dexamethasone (VAD) received VAD combined with thalidomide. Overall, a response was observed in 12 patients (50%). Of the 12 patients treated with low dose thalidomide alone 5 (42%) responded, of the 8 patients who received a combination of thalidomide and dexamethasone 5 (63%) responded and of the 4 patients who had thalidomide in addition to VAD 2 patients (50%) responded. In 3 patients, thalidomide treatment had to be discontinued because of side effects and 1 patient died before response could be assessed. We conclude that low dose thalidomide is an effective and safe rescue therapy in relapsing or refractory multiple myeloma. Response to thalidomide might be dependent on prognostic parameters and tumor burden. To answer these questions larger prospective studies are necessary.

Mast cell-lineage versus basophil lineage involvement in myeloproliferative and myelodysplastic syndromes: diagnostic role of cell-immunophenotyping.

Mast cells and blood basophils are distinct hemopoietic cells. They can be distinguished from each other and from all other lymphohemopoietic cells using antibodies against surface receptors or stored cytoplasmic molecules. In patients with myelodysplastic syndromes (MDS) or myeloproliferative syndromes (MPS), an elevation of metachromatically granulated cells (MCS) is frequently seen. These cells can be classified as basophils or mast cells using monoclonal antibodies (mAbs) against leukocyte antigens, including mast cell tryptase, c-kit (= mast cell growth factor [MGF] receptor), interleukin-3 receptor alpha chain (IL-3R alpha = CD123), and CD11b (C3biR). In a stable phase of MDS or MPS, the circulating MCS usually are basophils (histamine+, tryptase-, c-kit-, IL-3R alpha +, CD11b+). In an accelerated or terminal phase of disease, however, mast cell lineage involvement and circulating mast cell precursors (histamine+, tryptase+, c-kit+, IL-3R alpha-, CD11b-) are found in a subset of patients. The use of mAbs against mast cell antigens and granulocyte antigens is diagnostic in these patients.

Bone marrow mastocytosis associated with an undifferentiated extramedullary tumor of hemopoietic origin.

The case of a 62-year-old man who presented with acute abdominal pain and a widespread tumor involving the retroperitoneum is described. Three weeks after initial presentation, the patient died suddenly of acute cardiac failure with signs of arrhythmia. Autopsy revealed a disseminated tumor with infiltration of the retroperitoneal fat, as well as nodules in the left testis and the right atrium. The tumor cells were reactive for CD45, vimentin, and chloroacetate esterase, but were unreactive with a broad spectrum of antibodies against myelomonocytic and lymphocytic antigens and with antibodies against tryptase and c-kit (CD117), which are characteristic markers for mast cells. However, the bone marrow exhibited the typical picture of mastocytosis, with disseminated clusters of differentiated spindle-shaped cells that stained strongly for tryptase, c-kit, and chloroacetate esterase. No infiltrates of well-differentiated mastocytosis could be detected in any of the extramedullary tissues investigated. A diagnosis of bone marrow mastocytosis with an associated undifferentiated extramedullary tumor of hemopoietic origin was established. By definition, the extramedullary tumor could not be diagnosed as a granulocytic sarcoma or (differentiated) mastocytoma, but the possibility that a mast cell progenitor could be involved in the evolution of both tumors cannot be ruled out.

Rational use of polymerase chain reaction--based detection of viral genomes in patients with serologic markers of hepatitis B or C virus infection.

We studied the value of additional diagnostic information obtained by detection of hepatitis B virus (HBV) DNA or hepatitis C virus (HCV) RNA using the qualitative polymerase chain reaction (PCR) in patients with serologic markers of hepatitis B or hepatitis C virus infection. In HBV infection, all HBsAg+HBeAg+ patients and all HBsAg+HBeAg- patients with alanine aminotransferase (ALT) levels > 100 U/L were positive for HBV-DNA by PCR, whereas in HBsAg+HBeAg- patients with ALT < 100 U/L 58% and in HBsAg+HBeAg- patients with normal aminotransferase 45% were found to be positive. In HBsAg+ patients no further clinically useful information can be obtained by PCR as the presence of HBsAg proves infection. However in three of 42 (7%) patients with markers of past HBV infection (antiHBs and/or antiHBc+) HBV-DNA was detected in the serum. Similarly, in some patients with acute hepatitis B HBV-DNA was demonstrable up to four months after the disappearance of HBsAg from serum, pointing to persistence of viremia despite the loss of serological markers of ongoing HBV infection. Demonstrating ongoing HBV infection in patients with serological markers of past infection is valuable additional information in only selected patients. In HCV infection, 10% of anti-HCV+ patients with increased ALT levels had a negative serum HCV-RNA. However, in 20% of those patients HCV-RNA was demonstrated in a serum sample collected later during follow-up, indicating that a single negative HCV-RNA determination cannot be taken as evidence for the resolution of infection.

[Effector cells in allergy: biological principles and new pharmacologic concepts]. / Die Effektorzellen der Allergie: Biologische Grundlagen und neue pharmakologische Konzepte.

The clinical symptoms of allergy are caused by cellular (IgE-triggered) responses to an allergen. Effector cells of allergy include eosinophil and basophil granulocytes, as well as tissue mast cells. Growth and accumulation, as well as IgE-dependent and independent functions of these cells are regulated by distinct proteohormones and peptides. The hemopoietic cytokines IL-3 (interleukin-3), IL-5 and GM-CSF (granulocyte-macrophage colony-stimulating factor) are involved in the regulation of basophils (and eosinophils), whereas the ligand for c-kit, SCF (stem cell factor) is a mast cell-specific agonist. Basophils and mast cells express high-affinity IgE-binding sites. Allergen binding to IgE on mast cells and basophils, and consecutive cross-linking of IgE receptors is followed by production and/or secretion of inflammatory mediator substances. Specific activation and deactivation of mast cells/basophils in vitro has been demonstrated by use of recombinant cytokines and allergens, and specific haptens or by use of novel drugs, and should lead to epitope-specific diagnosis and better management of allergic diseases in the future.