Treatment of allergic rhinitis using mobile technology with real-world data: The MASK observational pilot study.

BACKGROUND: Large observational implementation studies are needed to triangulate the findings from randomized control trials as they reflect "real-world" everyday practice. In a pilot study, we attempted to provide additional and complementary insights on the real-life treatment of allergic rhinitis (AR) using mobile technology. METHODS: A mobile phone app (Allergy Diary, freely available in Google Play and Apple App stores) collects the data of daily visual analog scales (VAS) for (i) overall allergic symptoms, (ii) nasal, ocular, and asthma symptoms, (iii) work, as well as (iv) medication use using a treatment scroll list including all medications (prescribed and over the counter (OTC)) for rhinitis customized for 15 countries. RESULTS: A total of 2871 users filled in 17 091 days of VAS in 2015 and 2016. Medications were reported for 9634 days. The assessment of days appeared to be more informative than the course of the treatment as, in real life, patients do not necessarily use treatment on a daily basis; rather, they appear to increase treatment use with the loss of symptom control. The Allergy Diary allowed differentiation between treatments within or between classes (intranasal corticosteroid use containing medications and oral H1-antihistamines). The control of days differed between no [best control], single, or multiple treatments (worst control). CONCLUSIONS: This study confirms the usefulness of the Allergy Diary in accessing and assessing everyday use and practice in AR. This pilot observational study uses a very simple assessment (VAS) on a mobile phone, shows novel findings, and generates new hypotheses.

Daily allergic multimorbidity in rhinitis using mobile technology: A novel concept of the MASK study.

BACKGROUND: Multimorbidity in allergic airway diseases is well known, but no data exist about the daily dynamics of symptoms and their impact on work. To better understand this, we aimed to assess the presence and control of daily allergic multimorbidity (asthma, conjunctivitis, rhinitis) and its impact on work productivity using a mobile technology, the Allergy Diary. METHODS: We undertook a 1-year prospective observational study in which 4 210 users and 32 585 days were monitored in 19 countries. Five visual analogue scales (VAS) assessed the daily burden of the disease (i.e., global evaluation, nose, eyes, asthma and work). Visual analogue scale levels <20/100 were categorized as "Low" burden and VAS levels ≥50/100 as "High" burden. RESULTS: Visual analogue scales global measured levels assessing the global control of the allergic disease were significantly associated with allergic multimorbidity. Eight hypothesis-driven patterns were defined based on "Low" and "High" VAS levels. There were <0.2% days of Rhinitis Low and Asthma High or Conjunctivitis High patterns. There were 5.9% days with a Rhinitis High-Asthma Low pattern. There were 1.7% days with a Rhinitis High-Asthma High-Conjunctivitis Low pattern. A novel Rhinitis High-Asthma High-Conjunctivitis High pattern was identified in 2.9% days and had the greatest impact on uncontrolled VAS global measured and impaired work productivity. Work productivity was significantly correlated with VAS global measured levels. CONCLUSIONS: In a novel approach examining daily symptoms with mobile technology, we found considerable intra-individual variability of allergic multimorbidity including a previously unrecognized extreme pattern of uncontrolled multimorbidity.

Evaluation of avoralstat, an oral kallikrein inhibitor, in a Phase 3 hereditary angioedema prophylaxis trial: The OPuS-2 study.

BACKGROUND: Effective inhibition of plasma kallikrein may have significant benefits for patients with hereditary angioedema due to deficiency of C1 inhibitor (C1-INH-HAE) by reducing the frequency of angioedema attacks. Avoralstat is a small molecule inhibitor of plasma kallikrein. This study (OPuS-2) evaluated the efficacy and safety of prophylactic avoralstat 300 or 500 mg compared with placebo. METHODS: OPuS-2 was a Phase 3, multicenter, randomized, double-blind, placebo-controlled, parallel-group study. Subjects were administered avoralstat 300 mg, avoralstat 500 mg, or placebo orally 3 times per day for 12 weeks. The primary efficacy endpoint was the angioedema attack rate based on adjudicator-confirmed attacks. RESULTS: A total of 110 subjects were randomized and dosed. The least squares (LS) mean attack rates per week were 0.589, 0.675, and 0.593 for subjects receiving avoralstat 500 mg, avoralstat 300 mg, and placebo, respectively. Overall, 1 subject in each of the avoralstat groups and no subjects in the placebo group were attack-free during the 84-day treatment period. The LS mean duration of all confirmed attacks was 25.4, 29.4, and 31.4 hours for the avoralstat 500 mg, avoralstat 300 mg, and placebo groups, respectively. Using the Angioedema Quality of Life Questionnaire (AE-QoL), improved QoL was observed for the avoralstat 500 mg group compared with placebo. Avoralstat was generally safe and well tolerated. CONCLUSIONS: Although this study did not demonstrate efficacy of avoralstat in preventing angioedema attacks in C1-INH-HAE, it provided evidence of shortened angioedema episodes and improved QoL in the avoralstat 500 mg treatment group compared with placebo.

Google Trends terms reporting rhinitis and related topics differ in European countries.

Google Trends (GT) searches trends of specific queries in Google and reflects the real-life epidemiology of allergic rhinitis. We compared Google Trends terms related to allergy and rhinitis in all European Union countries, Norway and Switzerland from 1 January 2011 to 20 December 2016. The aim was to assess whether the same terms could be used to report the seasonal variations of allergic diseases. Using the Google Trend 5-year graph, an annual and clear seasonality of queries was found in all countries apart from Cyprus, Estonia, Latvia, Lithuania and Malta. Different terms were found to demonstrate seasonality depending on the country - namely 'hay fever', 'allergy' and 'pollen' - showing cultural differences. A single set of terms cannot be used across all European countries, but allergy seasonality can be compared across Europe providing the above three terms are used. Using longitudinal data in different countries and multiple terms, we identified an awareness-related spike of searches (December 2016).

Elevated plasma levels of vascular permeability factors in C1 inhibitor-deficient hereditary angioedema.

BACKGROUND: Hereditary angioedema with C1 inhibitor deficiency (C1-INH-HAE) is a rare inherited genetic disease characterized by recurrent swelling episodes of the skin, gastrointestinal tract, and upper airways. Angioedema attacks result from increased vascular permeability due to the release of bradykinin from high molecular weight kininogen. Currently, there are no biomarkers predicting the frequency of angioedema attacks. Vascular permeability is modulated by several factors, including vascular endothelial growth factors (VEGFs) and angiopoietins (Angs). As increased circulating levels of VEGFs and Angs have been observed in diseases associated with higher vascular permeability (e.g., systemic capillary leak syndrome and sepsis), we sought to analyze plasma concentrations of VEGFs and Angs in patients with C1-INH-HAE. METHODS: Sixty-eight healthy controls and 128 patients with C1-INH-HAE were studied. Concentrations of angiogenic (VEGF-A, Ang1, Ang2), anti-angiogenic (VEGF-A165b ) and lymphangiogenic (VEGF-C) factors were evaluated by ELISA. C1-INH functional activity was assessed by EIA. RESULTS: Plasma concentrations of VEGF-A, VEGF-C, Ang1, and Ang2 were higher in patients with C1-INH-HAE in remission than in healthy controls. Concentration of VEGF-A was further increased in patients with lower C1-INH functional activity. Patients with C1-INH-HAE experiencing more than 12 angioedema attacks per year were characterized by higher plasma levels of VEGF-A, VEGF-C, and Ang2 compared with the other patients. CONCLUSIONS: We hypothesize that VEGFs and Angs induce a state of 'vascular preconditioning' that may predispose to angioedema attacks. In addition, the identification of increased plasma levels of VEGFs and Angs in patients with C1-INH-HAE may prompt the investigation of VEGFs and Angs as biomarkers of C1-INH-HAE severity.

Oxidative stress markers are increased in patients with mastocytosis.

BACKGROUND: Mastocytosis is characterized by clonal proliferation of mast cells limited to the skin (cutaneous mastocytosis: CM and mastocytosis in the skin: MIS) and/or involving internal organs (systemic mastocytosis: SM). Oxidative stress occurring in various inflammatory and neoplastic disorders causes molecular damage with the production of advanced oxidation protein products (AOPPs) and advanced glycation end products (AGEs). We evaluated these markers of oxidative stress in patients with CM/MIS and SM and correlated their levels with the presence of symptoms related to mast cell activation. METHODS: Serum levels of AOPPs and AGEs in 34 patients with mastocytosis (23 CM/MIS and 11 SM) and 27 healthy controls were measured by spectrofluorimetric and spectrophotometric methods. Serum tryptase levels were measured by immunofluorescence. RESULTS: Serum AOPPs, but not AGEs, were significantly higher in patients with mastocytosis as compared to healthy controls. While serum tryptase levels were higher in patients with SM as compared to those with CM/MIS, there was no difference in AOPP and AGE concentrations between these two groups of patients. Patients with recurrent mediator-related symptoms had lower AOPPs and AGEs as compared to patients without symptoms. AOPPs and AGEs were inversely correlated with the severity of symptoms, and in patients with symptoms, AOPPs correlated with tryptase levels. DISCUSSION: Our data show that mastocytosis is associated with a state of increased oxidative stress that, in patients with mediator-related symptoms, correlates with mast cell burden as assessed by tryptase. Patients with symptoms presumably have an adaptive response resulting in lower blood levels of AOPPs and AGEs.

Management of chronic spontaneous urticaria: practical parameters.

Chronic urticaria (CU) is a skin disorder characterized by transient, pruritic wheals persisting for longer than 6 weeks. According to the European Academy of Allergy and Clinical Immunology (EAACI) guidelines, CU can be categorized into two main types: chronic spontaneous urticaria (CSU), in which the wheals appear spontaneously, and inducible urticaria, that is triggered by physical agents. CSU may be due to triggering factors such as food allergens or infections, but in at least 40% of cases it is autoimmune in origin, caused by circulating autoantibodies anti-FcεR1 or anti-IgE, or autoreactive. In the present paper, re-evaluating the EAACI guidelines, we have developed a document containing some practical indications which are useful for diagnosis and management of CSU in the context of the Italian situation. Concerning CSU treatment, second generation antihistamines are the first-line treatment; these drugs can be used, as second-line treatment, at a higher than licensed dose in patients who do not respond adequately at licensed doses. The third-line treatment includes leukotriene receptor antagonists which, however, do not have a specific indication for the treatment of CSU, cyclosporine, whose use in this disease is still off-label, and omalizumab. The latter is a recombinant monoclonal IgG antibody that binds free IgE, down regulates mast cell function and induces eosinophil apoptosis. Recently, it has emerged as an effective and safe treatment for antihistamine-unresponsive CSU of both autoimmune/autoreactive and non-autoimmune/non-autoreactive, and has been officially approved for use against this disease.

Refined diagnostic criteria and classification of mast cell leukemia (MCL) and myelomastocytic leukemia (MML): a consensus proposal.

Mast cell leukemia (MCL), the leukemic manifestation of systemic mastocytosis (SM), is characterized by leukemic expansion of immature mast cells (MCs) in the bone marrow (BM) and other internal organs; and a poor prognosis. In a subset of patients, circulating MCs are detectable. A major differential diagnosis to MCL is myelomastocytic leukemia (MML). Although criteria for both MCL and MML have been published, several questions remain concerning terminologies and subvariants. To discuss open issues, the EU/US-consensus group and the European Competence Network on Mastocytosis (ECNM) launched a series of meetings and workshops in 2011-2013. Resulting discussions and outcomes are provided in this article. The group recommends that MML be recognized as a distinct condition defined by mastocytic differentiation in advanced myeloid neoplasms without evidence of SM. The group also proposes that MCL be divided into acute MCL and chronic MCL, based on the presence or absence of C-Findings. In addition, a primary (de novo) form of MCL should be separated from secondary MCL that typically develops in the presence of a known antecedent MC neoplasm, usually aggressive SM (ASM) or MC sarcoma. For MCL, an imminent prephase is also proposed. This prephase represents ASM with rapid progression and 5%-19% MCs in BM smears, which is generally accepted to be of prognostic significance. We recommend that this condition be termed ASM in transformation to MCL (ASM-t). The refined classification of MCL fits within and extends the current WHO classification; and should improve prognostication and patient selection in practice as well as in clinical trials.

Classification, diagnosis, and approach to treatment for angioedema: consensus report from the Hereditary Angioedema International Working Group.

Angioedema is defined as localized and self-limiting edema of the subcutaneous and submucosal tissue, due to a temporary increase in vascular permeability caused by the release of vasoactive mediator(s). When angioedema recurs without significant wheals, the patient should be diagnosed to have angioedema as a distinct disease. In the absence of accepted classification, different types of angioedema are not uniquely identified. For this reason, the European Academy of Allergy and Clinical Immunology gave its patronage to a consensus conference aimed at classifying angioedema. Four types of acquired and three types of hereditary angioedema were identified as separate forms from the analysis of the literature and were presented in detail at the meeting. Here, we summarize the analysis of the data and the resulting classification of angioedema.

Proposed diagnostic algorithm for patients with suspected mastocytosis: a proposal of the European Competence Network on Mastocytosis.

Mastocytosis is an emerging differential diagnosis in patients with more or less specific mediator-related symptoms. In some of these patients, typical skin lesions are found and the diagnosis of mastocytosis can be established. In other cases, however, skin lesions are absent, which represents a diagnostic challenge. In the light of this unmet need, we developed a diagnostic algorithm for patients with suspected mastocytosis. In adult patients with typical lesions of mastocytosis in the skin, a bone marrow (BM) biopsy should be considered, regardless of the basal serum tryptase concentration. In adults without skin lesions who suffer from mediator-related or other typical symptoms, the basal tryptase level is an important parameter. In those with a slightly increased tryptase level, additional investigations, including a sensitive KIT mutation analysis of blood leucocytes or measurement of urinary histamine metabolites, may be helpful. In adult patients in whom (i) KIT D816V is detected and/or (ii) the basal serum tryptase level is clearly increased (>25-30 ng/ml) and/or (iii) other clinical or laboratory features suggest the presence of 'occult' mastocytosis or another haematologic neoplasm, a BM investigation is recommended. In the absence of KIT D816V and other signs or symptoms of mastocytosis or another haematopoietic disease, no BM investigation is required, but the clinical course and tryptase levels are monitored in the follow-up. In paediatric patients, a BM investigation is usually not required, even if the tryptase level is increased. Although validation is required, it can be expected that the algorithm proposed herein will facilitate the management of patients with suspected mastocytosis and help avoid unnecessary referrals and investigations.

Component resolved diagnosis (CRD): how much is it presently used by Italian allergists?

Component resolved diagnosis (CRD) represents an innovative and revolutionary tool in allergy diagnosis. At the same time, some criticisms can be outlined. The present web survey aimed at investigating the role of CRD in daily clinical practice, according to a sample of Italian specialists who manage allergic patients. 127 physicians, mostly allergists, completed the questionnaire, mainly coming from North and Center of Italy. Most of them (80%) were allergists. One physician out of three regularly takes into consideration CRD, that is currently available about in a half of the hospitals where the specialists work. CRD is mostly prescribed in the diagnostic work-up of suspected food allergy, as it can drive risk assessment, epinephrine prescription and dietary advice. Concerning respiratory allergy, CRD is considered useful in investigating cross-reactivity and in defining the best treatment option, even if only 32% of patients treated with immunotherapy had been previously studied with CRD. The present survey points out the need for the specialists to develop a more practical know-how about CRD. Its diagnostic accuracy and its real impact on the clinical management need to be better defined. The lacking of CRD technology in many hospitals limits the possibility for many allergists to directly experience molecular diagnosis.

Molecular diagnosis and the Italian Board for ISAC.

The Component Resolved Diagnostic (CRD) approach has been developed when highly purified or recombinant allergen molecules have become available. These molecules are the allergenic proteins toward which the specific and clinically relevant IgE immune response is directed. So, the identification of protein families and cross-reactivity patterns of importance in allergy have been possible. The Italian advisory BOARD for ISAC was born: to evaluate the advantages, disadvantages and placement in diagnosis of CRD studying its application in allergic patients; to facilitate the interpretation of molecular diagnostics for clinical allergists; to evaluate the effectiveness of CRD in improving diagnostic risk assessment and early preventive treatment of allergic diseases. In the last years, its fields of interest have been: the evaluation of the performance of CRD on multi-sensitized allergic patients with respiratory symptoms and on poly-sensitized athletes; the evolution of IgE repertoire directed to single allergenic components by evaluating allergic patients with different age at a molecular level; the relevance of results obtained using allergen microarray technique for describing the IgE repertoire in allergic patients by reviewing the main articles focused on CRD published in the last 2 years; the need for an educational program focused on this new diagnostic tool also through the creation of an exhaustive and interactive explanation of the laboratory report molecular allergy; the investigation of the performance and potential additional diagnostic values of the ISAC microarray in a real-life clinical setting, taking into account also the economic values.

The additional values of microarray allergen assay in the management of polysensitized patients with respiratory allergy.

BACKGROUND: The IgE response is directed against specific components from an allergenic source. The traditional diagnostic methods use whole extracts, containing allergenic, nonallergenic and cross-reactive molecules. This may pose diagnostic challenges in polysensitized patients. Microarray techniques detect specific IgE against multiple molecules, but their value in term of additional information and economic saving has not been yet defined. OBJECTIVE: We assessed the additional diagnostic information provided by an allergen microarray in a large population of polysensitized subjects. METHODS: In this multicentre study, allergists were required to carefully record diagnosis and treatment of consecutive patients referred for asthma/rhinitis, using the standard methodology (history, skin prick test, IgE assay). Then, a microarray allergen assay was carried out. Clinicians were required to review their diagnosis/treatment according to microarray results. RESULTS: 318 allergic patients (30% reporting also nonrespiratory symptoms) and 91 controls were enrolled. The clinicians reported at least one additional information from the microarray in about 60% of patients, this resulting in therapeutic adjustments. In 66% of patients IgE to pan-allergens were detectable, being this clinically relevant in 38% of patients with polysensitization to pollens. CONCLUSION: Microarray IgE assay represents an advancement in allergy diagnosis, as a third-level approach in polysensitized subjects, when the traditional diagnosis may be problematic.

Expression and function of Angiopoietins and their tie receptors in human basophils and mast cells.

The Angiopoietin/Tie system is a key regulator of vascular remodeling, maturation, angiogenesis and lymphangiogenesis. In humans there are three angiopoietins: Angiopoietin-1 (Ang1), Angiopoietin-2 (Ang2), and Angiopoietin-4 (Ang4). Ang1 and Ang2 are the best characterized angiopoietins. The angiopoietin receptor system consists of two type I tyrosine kinase receptors (Tie1 and Tie2). Tie2 binds all known angiopoietins. We sought to characterize Ang1, Ang2, Tie1 and Tie2 expression and functions in human basophils and mast cells. Basophils, LAD-2 cells and Human Lung Mast Cells (HLMCs) constitutively express Ang1 and Ang2 mRNA. Intracellular staining for Ang1 and Ang2 was stronger in basophils than in mast cells. Immunoelectron microscopy demonstrated Ang1 in cytoplasmic vesicles of basophils. The protein kinase C activators phorbol diester (PMA) and bryostatin 1 (Bryo1) stimulated basophils to rapidly release a large amount of Ang1. PMA-induced Ang1 release was inhibited by brefeldin A. Tie1 and Tie2 mRNAs were expressed in basophils, LAD-2 and HLMCs. Basophils, LAD-2 and HLMCs expressed Tie1 on the cell surface. HLMCs and LAD-2 expressed Tie2 on the cell surface, whereas basophils did not. Ang1, but not Ang2, induced migration of mast cells through the engagement of Tie2. Neither Ang1 nor Ang2 induced basophil chemotaxis. We have identified a novel mechanism of cross-talk between human basophils and mast cells mediated by the Ang1/Tie2 system that might be relevant in the orchestration of inflammatory and neoplastic angiogenesis.

Efficacy and safety of recombinant human C1-inhibitor for the treatment of attacks of hereditary angioedema: European open-label extension study.

BACKGROUND: Hereditary angioedema (HAE) owing to C1 inhibitor deficiency is an autosomal dominant disorder, characterized by recurrent, potentially life-threatening, localized attacks of tissue swelling. Current treatment involves the infusion of C1 inhibitor protein (C1-INH) isolated from human plasma. OBJECTIVES: This open-label extension to a European, Israeli and Argentinean randomized study (NCT00262301) aimed to investigate the efficacy and safety of recombinant human C1 inhibitor (rhC1-INH) as a first-line treatment following an HAE attack, together with its effect on subsequent attacks. METHODS: An HAE-specific visual analogue scale (VAS) 0-100 mm was used by patients to assess the severity of attack at four anatomical locations. Patients were treated with one, single-vial, fixed-dose of rhC1-INH (2100 U), followed by up to two further vials at the investigators discretion. The primary end-point was the time from first rhC1-INH injection to first onset of relief of symptoms (≥ 20 mm decrease on VAS). Response to treatment was defined as the onset of relief within 4 h. RESULTS: A total of 57 patients were treated for 194 HAE attacks. Overall, sustained relief of symptoms was achieved in 87% of rhC1-INH-treated patients within 4 h of treatment, with 57% of attacks requiring only one vial of rhC1-INH. When categorized by successive attacks experienced by individual patients, the response rate to rhC1-INH treatment was 96%, 83%, 87%, 80% and 80% for attacks 1-5 respectively. Treatment with rhC1-INH was well tolerated, with no discontinuations owing to treatment-emergent adverse events and no adverse events relating to immunogenicity. CONCLUSIONS AND CLINICAL RELEVANCE: Treatment with rhC1-INH provides fast-onset relief for an HAE attack, with a high rate of therapeutic response maintained throughout subsequent attacks.

Icatibant treatment for acquired C1-inhibitor deficiency: a real-world observational study.

Icatibant, a bradykinin B2 receptor antagonist, is an established treatment for acute attacks of hereditary angioedema (HAE) with C1-inhibitor (C1-INH) deficiency. We describe our experience with icatibant in eight patients with angioedema because of acquired C1-INH deficiency (AAE). Forty-eight moderate-to-severe attacks were treated with subcutaneous icatibant 30 mg; two moderate attacks resolved without treatment. The median (range) duration of treated attacks (onset to complete resolution) was 9.33 (1.67-39.00) h; durations of the untreated attacks were 72 and 96 h. Symptom improvement following icatibant treatment occurred in 0.5 (0.25-2.10) h and complete resolution in 6.75 (0.50-30.75) h. A single icatibant injection achieved complete symptom resolution in 47 attacks; one facial attack required a second injection. One peripheral attack responded less quickly than other treated attacks. Five patients reported transient injection site reactions. Icatibant appeared to provide effective symptom relief and was generally well tolerated.

Migration of human inflammatory cells into the lung results in the remodeling of arachidonic acid into a triglyceride pool.

Increasing evidence suggests that the metabolism of arachidonic acid (AA) may be different in inflammatory cells isolated from blood or migrating into tissues. To explore the possibility that changes in AA metabolism between blood and tissue inflammatory cells could be due in part to a different content or distribution of AA in glycerolipid classes, we studied these parameters in six human inflammatory cells isolated from blood (eosinophils, monocytes, neutrophils, and platelets) or from the lung tissue (mast cells and macrophages). Lung cells generally had a higher total cellular content of AA than that found in the blood cells. In addition, both mast cells and macrophages had a large endogenous pool of AA associated with triglycerides (TG), containing 45 and 22% of their total cellular AA, respectively. To address the hypothesis that cells migrating into the lung had a higher cellular level of AA and a larger AA pool in TG, we studied neutrophils isolated from the bronchoalveolar lavage (BAL) of patients with adult respiratory distress syndrome. BAL neutrophils had a fourfold increase in cellular AA as compared with blood neutrophils and contained 25% of their AA in TG versus 3% in blood neutrophils. BAL neutrophils also had a higher number of cytoplasmic lipid bodies (8 +/- 3/cell) relative to blood neutrophils (2 +/- 1/cell). High concentrations of free AA were also found in the cell-free BAL fluid of adult respiratory distress syndrome patients. To explore whether changes in BAL neutrophils may be due to the exposure of the cells to high concentrations of exogenous AA found in BAL, we incubated blood neutrophils in culture with AA (10-100 microM) for 24 h. Neutrophils supplemented with AA had a 10-fold increase in the amount of AA associated with TG and a sixfold increase in the number of lipid bodies. In addition, supplementation with AA induced a dose-dependent formation of hypodense cells. Taken together, these data indicate that human inflammatory cells undergo a fundamental and consistent remodeling of AA pools as they mature or enter the lung from the blood. These biochemical and morphological changes can be mimicked in vitro by exposing the cells to high levels of AA. This mechanism may be responsible for the changes in AA mobilization and eicosanoid metabolism observed in tissue inflammatory cells.

Antigen-induced generation of lyso-phospholipids in human airways.

The goal of the current study was to examine the formation of phospholipids, 1-radyl-2-lysosn-glycero-phospholipids (lyso-PL) and 2-acetylated phospholipids (such as PAF) as well as mechanisms responsible for generating these phospholipids in bronchoalveolar lavage fluid (BAI.F) from allergic subjects challenged with antigen. Bronchoalveolar lavage was performed in normal and allergic subjects before, 5-30 min, 6 h, and 20 h after segmental antigen challenge via a wedged bronchoscope. Levels of 1-hexadecyl-2-lyso-phospholipids and 1-hexadecyl-2-acetyl-phospholipids were initially determined by negative ion chemical ionization gas chromatography/mass spectrometry (NICI-GC/MS). Antigen dramatically elevated quantities of 1-hexadecyl-2-lyso-phospholipids in allergic subjects 20 h after challenge when compared to non-allergic controls. In contrast, there was not a significant increase in levels of 1-hexadecyl-2-acetyl-phospholipids after antigen challenge. Closer examination of 1-radyl-2-lyso-sn-glycero-3-phosphocholine (GPC) revealed that 1-palmitoyl-2-lyso-GPC, 1-myristoyl-2-lyso-GPC and 1-hexadecyl-2-lyso-GPC were three major molecular species produced after antigen challenge. 1-palmitoyl-2-lyso-GPC increased sevenfold to levels of 222 +/- 75 ng/ml of BALF 20 h after antigen challenge. The elevated levels of lyso-PL correlated with levels of albumin used to assess plasma exudation induced by allergen challenge. In contrast, the time course of prostaglandin D2 (PGD2) or 9 alpha, 11 beta PGF2 (11 beta PGF2) formation did not correlate with lyso-PL generation. To examine the mechanism leading to lyso-phospholipid formation in antigen-challenged allergic subjects, secretory phospholipase A2 (PI.A2) and acetyl hydrolase activities were measured. There was a significant increase in PLA2 activity found in BALF of allergic subjects challenged with antigen when compared to saline controls. This activity was neutralized by an antibody directed against low molecular mass, (14 kD) human synovial PLA2 and dithiothreitol. Acetyl hydrolase activity also markedly increased in BALF obtained after antigen challenge. This study indicates that high levels of lyso-PLs are present in airways of allergic subjects challenged with antigen and provides evidence for two distinct mechanisms that could induce lyso-PL formation. Future studies will be necessary to determine the ramifications of these high levels of lyso-phospholipids on airway function.

Benzene metabolites inhibit the release of proinflammatory mediators and cytokines from human basophils.

Benzene and its metabolites have been involved in the pathogenesis of chronic lung inflammation and allergic disorders such as bronchial asthma. However, the effects of these xenobiotics on human basophils, key cells in the development of respiratory allergy, have not been investigated. We examined the effects of hydroquinone (HQ) and benzoquinone (BQ), two important chemicals implicated in benzene toxicity, on the release of preformed (histamine) and de novo synthesized mediators (cysteinyl leukotriene C4, LTC4, and IL-4) from human basophils. Preincubation of basophils purified from normal donors with HQ (3-100 microM) inhibited up to 30% histamine release induced by anti-IgE and up to 55% of that induced by the Ca2+ ionophore A23187. HQ had no effect on histamine release induced by formyl-methionyl-leucyl-phenylalanine (f-Met-Leu-Phe). Preincubation of basophils with BQ (3-100 microM) resulted in the concentration-dependent inhibition of histamine release (up to 70%) induced by anti-IgE, A23187 and f-Met-Leu-Phe. HQ completely suppressed the de novo synthesis of LTC4 from basophils challenged with anti-IgE or f-Met-Leu-Phe and the production of IL-4 in cells stimulated with anti-IgE. These results indicate that two major benzene metabolites, HQ and BQ, inhibit the release of proinflammatory mediators and Th2-promoting cytokines from basophils activated by different stimuli. These results suggest that benzene metabolites interfere with multiple intracellular signals involved in the activation of human basophils.