Wolfgang R. Sperr

Standards and standardization in mastocytosis: Consensus Statements on Diagnostics, Treatment Recommendations and Response Criteria

Although a classification for mastocytosis and diagnostic criteria are available, there remains a need to define standards for the application of diagnostic tests, clinical evaluations, and treatment responses. To address these demands, leading experts discussed current issues and standards in mastocytosis in a Working Conference. The present article provides the resulting outcome with consensus statements, which focus on the appropriate application of clinical and laboratory tests, patient selection for interventional therapy, and the selection of appropriate drugs. In addition, treatment response criteria for the various clinical conditions, disease‐specific symptoms, and specific pathologies are provided. Resulting recommendations and algorithms should greatly facilitate the management of patients with mastocytosis in clinical practice, selection of patients for therapies, and the conduct of clinical trials.

Definitions, Criteria and Global Classification of Mast Cell Disorders with Special Reference to Mast Cell Activation Syndromes: A Consensus Proposal

Activation of tissue mast cells (MCs) and their abnormal growth and accumulation in various organs are typically found in primary MC disorders also referred to as mastocytosis. However, increasing numbers of patients are now being informed that their clinical findings are due to MC activation (MCA) that is neither associated with mastocytosis nor with a defined allergic or inflammatory reaction. In other patients with MCA, MCs appear to be clonal cells, but criteria for diagnosing mastocytosis are not met. A working conference was organized in 2010 with the aim to define criteria for diagnosing MCA and related disorders, and to propose a global unifying classification of all MC disorders and pathologic MC reactions. This classification includes three types of ‘MCA syndromes’ (MCASs), namely primary MCAS, secondary MCAS and idiopathic MCAS. MCA is now defined by robust and generally applicable criteria, including (1) typical clinical symptoms, (2) a substantial transient increase in serum total tryptase level or an increase in other MC-derived mediators, such as histamine or prostaglandin D2, or their urinary metabolites, and (3) a response of clinical symptoms to agents that attenuate the production or activities of MC mediators. These criteria should assist in the identification and diagnosis of patients with MCAS, and in avoiding misdiagnoses or overinterpretation of clinical symptoms in daily practice. Moreover, the MCAS concept should stimulate research in order to identify and exploit new molecular mechanisms and therapeutic targets.

Allergen-specific immunotherapy with a monophosphoryl lipid A-adjuvanted vaccine: reduced seasonally boosted immunoglobulin E production and inhibition of basophil histamine release by therapy-induced blocking antibodies.

Background Allergen‐specific immunotherapy represents a causal form of treatment for IgE‐mediated allergies. The allergen extract‐based analyses of immunotherapy‐induced effects yielded highly controversial results regarding a beneficial role of therapy‐induced IgG antibodies.

Conversion of the major birch pollen allergen, Bet v 1, into two nonanaphylactic T cell epitope-containing fragments: candidates for a novel form of specific immunotherapy.

A novel approach to reduce the anaphylactic activity of allergens is suggested. The strategy makes use of the presence of conformational immunoglobulin E (IgE) epitopes on one of the most common allergens. The three dimensional structure of the major birch pollen allergen, Bet v 1, was disrupted by expressing two parts of the Bet v 1 cDNA representing amino acids 1-74 and 75-160 in Escherichia coli. In contrast to the complete recombinant Bet v 1, the fragments showed almost no allergenicity and exhibited random coil conformation as analyzed by circular dichroism. Both nonanaphylactic fragments induced proliferation of human Bet v 1-specific T cell clones, indicating that they harbored all dominant T cell epitopes and therefore may be considered as a basis for the development of a safe and specific T cell immunotherapy.

Recombinant Carp Parvalbumin, the Major Cross-Reactive Fish Allergen: A Tool for Diagnosis and Therapy of Fish Allergy

IgE-mediated reactions to fish allergens represent one of the most frequent causes of food allergy. We have constructed an expression cDNA library from carp (Cyprinus carpio) muscle in phage λgt11 and used serum IgE from a fish allergic patient to isolate 33 cDNA clones that coded for two parvalbumin isoforms (Cyp c 1.01 and Cyp c 1.02) with comparable IgE binding capacities. Both isoforms represented calcium-binding proteins that belonged to the β-lineage of parvalbumins. The Cyp c 1.01 cDNA was overexpressed in Escherichia coli, and rCyp c 1.01 was purified to homogeneity. Circular dichroism analysis and mass spectroscopy showed that rCyp c 1.01 represented a folded protein with mainly α-helical secondary structure and a molecular mass of 11,416 Da, respectively. rCyp c 1.01 reacted with IgE from all fish-allergic patients tested (n = 60), induced specific and dose-dependent basophil histamine release, and contained most of the IgE epitopes (70%) present in natural allergen extracts from cod, tuna, and salmon. Therefore, it may be used to identify patients suffering from IgE-mediated fish allergy. The therapeutic potential of rCyp c 1.01 is indicated by our findings that rabbit Abs raised against rCyp c 1.01 inhibited the binding of IgE (n = 25) in fish-allergic patients to rCyp c 1.01 between 35 and 97% (84% mean inhibition) and that depletion of calcium strongly reduced IgE recognition of rCyp c 1.01. The latter results suggest that it will be possible to develop strategies for immunotherapy for fish allergy that are based on calcium-free hypoallergenic rCyp c 1.01 derivatives.

Treatment of periodontal pockets with a diode laser

The aim of this study is to examine the long‐term effect of diode laser therapy on periodontal pockets with regard to its bactericidal abilities and the improvement of periodontal condition.

Diagnosis and treatment of systemic mastocytosis: state of the art

Mast cells are tissue-fixed cells originating from uncommitted and mast cell-committed haematopoietic progenitors (Kitamura et al, 1981; Kirshenbaum et al, 1992; Agis et al, 1993; Rottem et al, 1994; Kempuraj et al, 1999). Mast cellcommitted progenitors co-express CD13 and KIT with CD34 (Kirshenbaum et al, 1999) and are detectable in the bone marrow as well as in the peripheral blood (Valent et al, 1992; Rottem et al, 1994; Valent, 1994). Homing, differentiation and maturation of mast cell progenitor cells are regulated by a complex network of growth factors, receptors and other antigens (Galli, 1990; Valent, 1994). The most important growth factor for human mast cells appears to be stem cell factor (SCF) (Irani et al, 1992; Kirshenbaum et al, 1992; Valent et al, 1992; Mitsui et al, 1993). This cytokine is a natural ligand for the c-kit proto-oncogene product, KIT, a tyrosine kinase receptor expressed on the surface of precommitted myelopoietic progenitor cells, mast cell-committed progenitor cells as well as mature mast cells (Galli et al, 1993; Simmons et al, 1994; Valent, 1994). Based on their unique phenotype and distinct functional properties, mast cells represent a distinct myeloid cell lineage within lympho-haematopoietic tissues. Likewise, mast cells express a unique composition of CD antigens and granular mediators when compared with other myeloid cells (Schwartz, 1985; Valent et al, 1989; Valent & Bettelheim, 1992; Agis et al, 1996) (Table I). Moreover, in contrast to blood basophils and other myeloid cells, mast cells exhibit an extremely long life span in vivo ranging from several months to years (Galli, 1990; Födinger et al, 1994). In contrast to other haematopoietic cells, mast cells produce substantial amounts of histamine and heparin and express the high-affinity IgE receptor on their surface (Ishizaka & Ishizaka, 1984; Schwartz, 1985; Galli, 1990). The concept that mast cells represent a unique myeloid lineage is in line with the notion that systemic mastocytosis (SM) is a distinct haematopoietic (myeloid) neoplasm with unique pathogenetic and clinical features (Lennert & Parwaresch, 1979; Parwaresch et al, 1985; Metcalfe, 1991a; Valent, 1996). The clonal nature of the disease has been reinforced by the association with the somatic c-kit mutation Asp-816-Val (Nagata et al, 1995; Longley et al, 1996, 1999; Buttner et al, 1998). This transforming mutation is detectable in the bone marrow (mast cells) in a majority of patients with SM but usually is not found in other myeloid neoplasms (Fritsche-Polanz et al, 2001). Remarkably, in a group of patients with (advanced) SM, the c-kit mutation Asp-816-Val is detectable not only in mast cells but also in other haematopoietic lineages, including blood monocytes (Akin et al, 2000a; Sotlar et al, 2000; Yavuz et al, 2002). Based on this notion and several clinical observations, SM can be regarded as a myeloproliferative disorder. In line with this concept, patients with SM are at a certain risk of acquiring a secondary myeloid leukaemia (Travis et al, 1988a,b; Horny et al, 1990a; Lawrence et al, 1991; Sperr et al, 2000). In the management of patients with SM, two major problems have to be faced. The first is mediator release from mast cells with respective clinical symptoms that can be observed frequently in these patients (Horan & Austen, 1991; Metcalfe, 1991a; Austen, 1992; Valent, 1996). In fact, mast cells store (in their granules) or generate a number of vasoactive mediators [histamine, tumour necrosis factor-a (TNFa), vascular endothelial growth factor (VEGF), leukotrienes, prostaglandin D2 (PGD2)] and other biologically active molecules (interleukins, proteases, heparin) (Roberts et al, 1980; Lewis & Austen, 1981; Serafin & Austen, 1987; Burd et al, 1989; Plaut et al, 1989; WodnarFilipowicz et al, 1989; Gordon et al, 1990; Gordon & Galli, 1990) (Table II). In response to activating stimuli, mast cells can generate and ⁄ or release their mediator substances (Lewis & Austen, 1981; Ishizaka & Ishizaka, 1984; Schwartz, 1985; Burd et al, 1989; Plaut et al, 1989; Wodnar-Filipowicz et al, 1989; Gordon et al, 1990). Resulting clinical symptoms include headache, flushing, pruritus, diarrhoea, vascular instability, hypotension and shock (Austen, 1992) (Table II). Such symptoms may be grave and life threatening, especially in patients with SM who also have a co-existing disease predisposing for mediator secretion (allergies). The second management problem in SM results from the uncontrolled (aggressive) growth and infiltration of mast cells in diverse organs with consecutive organopathy (Lennert & Parwaresch, 1979; Parwaresch et al, 1985; Metcalfe, 1991a; Valent, 1996). Such organopathies are seen in patients with aggressive systemic mastocytosis (ASM), mast cell leukaemia (MCL) and in a group of patients with an associated clonal haematological nonmast cell lineage disease (SM-AHNMD), but not in those with indolent systemic mastocytosis (ISM). The organ systems most frequently affected in patients with aggressive Correspondence: Peter Valent, Department of Internal Medicine I, Division of Haematology & Haemostaseology, University of Vienna, Währinger Gürtel 18–20, A-1090 Vienna, Austria. E-mail: peter.valent@akh-wien.ac.at British Journal of Haematology, 2003, 122, 695–717

Aggressive systemic mastocytosis and related mast cell disorders: current treatment options and proposed response criteria

Aggressive systemic mastocytosis (ASM) is a clonal mast cell disease characterized by progressive growth of neoplastic cells in diverse organs leading to organopathy. The organ-systems most frequently affected are the bone marrow, skeletal system, liver, spleen, and the gastrointestinal tract. Respective clinical findings (so called C-Findings) include cytopenias, osteolysis (or osteoporosis) with pathologic fractures, hepatosplenomegaly with impaired liver function and ascites, and malabsorption. During the past decade several treatment strategies for ASM have been proposed. One promising approach may be combination treatment with interferon-alpha (IFN-alpha) and glucocorticoids. This concept has been based on the notion that systemic mastocytosis involves multilineage hematopoietic progenitors indicating a relationship with myeloproliferative disorders. However, relatively little is known about the quality of responses to IFN-alpha in ASM and the actual response rates. This may be due in part to the fact that disease criteria for ASM have only recently been established, and no response criteria are available. In the current article, we propose surrogate markers and treatment response criteria for patients with ASM. In addition, we have applied these criteria retrospectively to ASM patients described in the available literature. In these analyses, the calculated rate of major response (=complete resolution of C-Findings) in patients treated with IFN-alpha (with or without additional glucocorticoids) amounts to approximately 21%. This confirms clinical activity in some patients for this drug-combination, but also points to the need to search for more effective strategies in the treatment of patients with aggressive mast cell disorders.

Induction of antibody responses to new B cell epitopes indicates vaccination character of allergen immunotherapy.

Whether the modulation of antibody responses can contribute to the improvement of clinical symptoms in patients receiving allergen immunotherapy represents a controversial issue. We have used purified [seven recombinant (r) and one natural] timothy grasspollen allergens as well as recombinant B cell epitope‐containing fragments of the major timothy grass pollen allergen, Phl p 1, to investigate humoral immune responses in eight allergic patients receiving grass pollen‐specific immunotherapy. We found that the administration of aluminium hydroxide‐adsorbed grass pollen extract induced complex changes in allergen / epitope‐specific antibody responses: increases in IgG subclass (IgG1, IgG2, IgG4) responses against allergens recognized before the therapy were observed. All eight patients started to mount IgE and IgG4 responses to continuous Phl p 1 epitopes not recognized before the therapy and a de novo induction of IgE antibodies against new allergens was found in one patient. Evidence for a protective role of IgG antibodies specific for continuous Phl p 1 epitopes was provided by the demonstration that preincubation of rPhl p 1 with human serum containing therapy‐induced Phl p 1‐specific IgG inhibited rPhl p 1‐induced histamine release from basophils of a grass pollen‐allergic patient. Our finding that immunotherapy induced antibody responses against previously not recognized B cell epitopes indicates the vaccination character of this treatment. The fact that patients started to mount de novo IgE as well as protective IgG responses against epitopes may explain the unpredictability of specific immunotherapy performed with allergen extracts and emphasizes the need for novel forms of component‐resolved immunotherapy.

Purification, biochemical, and immunological characterisation of a major food allergen: different immunoglobulin E recognition of the apo- and calcium-bound forms of carp parvalbumin

BACKGROUND Almost 4% of the population suffer from food allergy which is an adverse reaction to food with an underlying immunological mechanism. AIMS To characterise one of the most frequent IgE defined food allergens, fish parvalbumin. METHODS Tissue and subcellular distribution of carp parvalbumin was analysed by immunogold electron microscopy and cell fractionation. Parvalbumin was purified to homogeneity, analysed by mass spectrometry and circular dichroism (CD) spectroscopy, and its allergenic activity was analysed by IgE binding and basophil histamine release tests. RESULTS The isoelectric point (pI) 4.7 form of carp parvalbumin, a three EF-hand calcium-binding protein, was purified to homogeneity. CD analysis revealed a remarkable stability and refolding capacity of calcium-bound parvalbumin. This may explain why parvalbumin, despite cooking and exposure to the gastrointestinal tract, can sensitise patients. Purified parvalbumin reacted with IgE of more than 95% of individuals allergic to fish, induced dose-dependent basophil histamine release and contained, on average, 83% of the IgE epitopes present in other fish species. Calcium depletion reduced the IgE binding capacity of parvalbumin which, according to CD analysis, may be due to conformation-dependent IgE recognition. CONCLUSIONS Purified carp parvalbumin represents an important cross reactive food allergen. It can be used for in vitro and in vivo diagnosis of fish-induced food allergy. Our finding that the apo-form of parvalbumin had a greatly reduced IgE binding capacity indicates that this form may be a candidate for safe immunotherapy of fish-related food allergy.