Short-chain fatty acids induce tissue plasminogen activator in airway epithelial cells via GPR41&43.

BACKGROUND: Chronic rhinosinusitis (CRS) is a heterogeneous chronic inflammatory disease generally divided based on the presence or absence of nasal polyps (NPs). One of the features of NPs is excessive fibrin deposition, which is associated with down-regulation of tissue plasminogen activator (t-PA) in NPs. As t-PA is expressed in epithelial cells, and epithelium is readily accessible to topical therapies, identifying compounds that can mediate the induction of t-PA would be a potential new strategy for the treatment of NPs. OBJECTIVE: The objective of this study was to determine whether short-chain fatty acids (SCFAs) can induce t-PA in airway epithelial cells via their known receptors GPR41 and GPR43. METHODS: We performed immunohistochemistry (IHC) to determine whether receptors for SCFAs, known as G protein-coupled receptor 41/free fatty acid receptor 3 (GPR41/FFAR3) and GPR43/FFAR2, are expressed in nasal tissue. Primary normal human bronchial epithelial (NHBE) cells were stimulated with different concentrations of SCFAs to test induction of t-PA, which was analysed by expression of mRNA and protein. Mediation of responses by SCFA receptors was evaluated by specific receptor gene silencing with siRNA. RESULTS: Immunohistochemistry study revealed that airway epithelial cells expressed GPR41 and GPR43. Acetic acid, propionic acid, butyric acid and valeric acid significantly induced t-PA expression from two- to tenfolds. The strongest inducer of t-PA from NHBE cells was propionic acid; cells stimulated with propionic acid released t-PA into the supernatant in its active form. Gene silencing of GPR41 and GPR43 revealed that induction of t-PA by SCFAs was dependent upon both GPR41 and GPR43. CONCLUSIONS AND CLINICAL RELEVANCE: Short-chain fatty acids were shown to induce airway epithelial cell expression of t-PA via GPR41 and GPR43. Topical delivery of potent compounds that activate these receptors may have value by reducing fibrin deposition and shrinking nasal polyp growth.

Chronic airway inflammation provides a unique environment for B cell activation and antibody production.

BACKGROUND: B cells play many roles in health and disease. However, little is known about the mechanisms that drive B cell responses in the airways, especially in humans. Chronic rhinosinusitis (CRS) is an inflammatory disease of the upper airways that affects 10% of Europeans and Americans. A subset of CRS patients develop nasal polyps (NPs), which are characterized by type 2 inflammation, eosinophils and group 2 innate lymphoid cells (ILC2s). We have reported that NP contain elevated levels of B cells and antibodies, making NP an ideal system for studying B cells in the airways. OBJECTIVE: We sought to determine the mechanisms that drive B cell activation and antibody production during chronic airway inflammation. METHODS: We analysed B cells from NP or tonsil, or after ILC2 coculture, by flow cytometry. Antibody production from tissue was measured using Luminex assays and the frequency of antibody-secreting cells by ELISpot. Formation of B cell clusters was assessed using immunohistochemistry. Expression of genes associated with B cell activation and class switch recombination was measured by qRT-PCR. RESULTS: NP contained significantly elevated frequencies of plasmablasts, especially those that expressed the extrafollicular marker Epstein-Barr virus-induced protein 2 (EBI2), but significantly fewer germinal centre (GC) B cells compared with tonsil. Antibody production and the frequency of antibody-secreting cells were significantly elevated in NP, and there was evidence for local class switch recombination in NP. Finally, ILC2s directly induced EBI2 expression on B cells in vitro. CONCLUSIONS AND CLINICAL RELEVANCE: Our data suggest there is a unique B cell activation environment within NP that is distinct from classic GC-mediated mechanisms. We show for the first time that ILC2s directly induce EBI2 expression on B cells, indicating that ILC2s may play an important role in B cell responses. B cell-targeted therapies may provide new treatment options for CRSwNP.

Elevated presence of myeloid dendritic cells in nasal polyps of patients with chronic rhinosinusitis.

BACKGROUND: Although chronic rhinosinusitis with nasal polyps (CRSwNP) is characterized by Th2 inflammation, the mechanism underlying the onset and amplification of this inflammation has not been fully elucidated. Dendritic cells (DCs) are major antigen-presenting cells, central inducers of adaptive immunity and critical regulators of many inflammatory diseases. However, the presence of DCs in CRS, especially in nasal polyps (NPs), has not been extensively studied. OBJECTIVE: The objective of this study was to characterize DC subsets in CRS. METHODS: We used real-time PCR to assess the expression of mRNA for markers of myeloid DCs (mDCs; CD1c), plasmacytoid DCs (pDCs; CD303) and Langerhans cells (LCs; CD1a, CD207) in uncinate tissue (UT) from controls and patients with CRS as well as in NP. We assayed the presence of DCs by immunohistochemistry and flow cytometry. RESULTS: Compared to UT from control subjects (n = 15) and patients with CRS without NP (CRSsNP) (n = 16) and CRSwNP (n = 17), mRNAs for CD1a and CD1c were significantly elevated in NPs (n = 29). In contrast, CD207 mRNA was not elevated in NPs. Immunohistochemistry showed that CD1c(+) cells but not CD303(+) cells were significantly elevated in NPs compared to control subjects or patients with CRSsNP. Flow cytometric analysis showed that CD1a(+) cells in NPs might be a subset of mDC1s and that CD45(+) CD19(-) CD1c(+) CD11c(+) CD141(-) CD303(-) HLA-DR(+) mDC1s and CD45(+) CD19(-) CD11c(+) CD1c(-) CD141(high) HLA-DR(+) mDC2s were significantly elevated in NPs compared to UT from controls and CRSsNP, but CD45(+) CD11c(-) CD303(+) HLA-DR(+) pDCs were only elevated in NPs compared to control UT. CONCLUSION AND CLINICAL RELEVANCE: Myeloid DCs are elevated in CRSwNP, especially in NPs. Myeloid DCs thus may indirectly contribute to the inflammation observed in CRSwNP.

Reduced expression of antimicrobial PLUNC proteins in nasal polyp tissues of patients with chronic rhinosinusitis.

BACKGROUND: Chronic rhinosinusitis (CRS) is a disease characterized by inflammation of the nasal mucosa and paranasal sinuses. This inflammation may result in part from decreased epithelial barrier and innate immune responses, leading to frequent bacterial and fungal colonization. The objectives of this study were to investigate the expression of innate immune proteins of the palate lung and nasal epithelium clone (PLUNC) family in patients with CRS. METHODS: Nasal tissue samples were collected from control subjects and CRS patients with and without nasal polyps. Expression of the members of the PLUNC family was analyzed by real-time PCR. Expression of SPLUNC1 and LPLUNC2 proteins was analyzed by ELISA, immunoblot, and immunohistochemical analysis. RESULTS: Levels of mRNA for most of the members of the PLUNC family were profoundly reduced in nasal polyps (NPs) compared to uncinate tissue from control subjects or patients with CRS. LPLUNC2 and SPLUNC1 proteins were decreased in NPs of patients with CRS compared to uncinate tissue from control subjects. Immunohistochemical data revealed that within submucosal glands of sinonasal tissues, SPLUNC1 and LPLUNC2 were differentially expressed, in serous and mucous cells, respectively. The decrease in the expression of these molecules is probably explained by a decrease in the number of glands in NPs as revealed by correlations with levels of the glandular marker lactoferrin. CONCLUSIONS: Decreased SPLUNC1 and LPLUNC2 in NPs reflect a profound decrease in the number of submucosal glands. Decreased glands may lead to a localized defect in the production and release of glandular innate defense molecules.

Using test dose challenges to restore essential therapy in patients with idiopathic anaphylaxis and pharmacophobia: report of a patient with idiopathic anaphylaxis and statin phobia.

Idiopathic anaphylaxis (IA) is a well-documented condition in which anaphylaxis occurs in the absence of an identifiable precipitant. However, many patients with IA find it difficult to accept this diagnosis and continue to search for an external cause. It is not uncommon for these highly anxious patients to discontinue essential medications that they feel are responsible for the reaction despite reassurance from their physicians to the contrary. In extreme cases, these patients may develop an actual phobia to preexisting medications and avoid them despite adverse consequences to their health. To illustrate this concept, we report a case involving a female patient with familial hypercholesterolemia who experienced a single episode of IA and developed a "statin phobia," falsely implicating her medication (lovastatin) for the reaction. After 5 years of failed therapy with other antihyperlipidemic agents, the patient finally agreed to undergo test dosing to a similar statin agent atorvastatin. On successful completion of the test, she resumed therapy with atorvastatin and her low-density lipoprotein (LDL) levels were reduced by 50% over 5 months. We conclude that patients with a confirmed diagnosis of IA who manifest phobic responses to beneficial medications should be reassured of the diagnosis promptly by their physician. When reassurance fails and the medication is essential to the patient's health, test dose challenges may be conducted to reintroduce the drug to the patient's regimen.

Lymphocyte subsets and activation markers in patients with acute episodes of idiopathic anaphylaxis.

BACKGROUND: Idiopathic anaphylaxis (IA), a type of anaphylaxis in which no external allergen can be identified, is a corticosteroid-responsive disease, that suggests that it may have an immunologic pathogenesis. OBJECTIVE: The objective of this study is to compare patients with acute episodes of IA with normals, patients with chronic idiopathic urticaria, and patients with IA in remission relative to lymphocyte subsets and activation markers. METHODS: This is a prospective cohort study of 38 adults: 5 normals, 4 idiopathic urticaria, 11 IA patients in remission, 9 IA patients with acute attacks who had not yet received prednisone, and 9 IA patients who had received prednisone. The main outcome measures were lymphocyte subset and activation markers determined by two and three color flow cytometry (CD2, CD3, CD4, CD5, CD8, CD16, CD19, CD23, CD25, CD56, and HLA-DR). RESULTS: Comparing patients with acute IA with those in remission, the only significant difference was that the acute IA patients had a significantly higher percentage of CD3+HLA-DR+ cells. Normals had a significantly lower percentage of CD3+ HLA-DR+ cells than all other groups. Patients with acute IA on prednisone as well as IA patients in remission had a significantly higher percentage of CD 19+ CD23+ cells than normals. CONCLUSIONS: These results suggest that there are more activated T cells in patients with acute episodes of IA than in patients in remission. Perhaps, these activated T cells have a role in the pathogenesis of IA.

Multicenter, double-blind, placebo-controlled, multiple-challenge evaluation of reported reactions to monosodium glutamate.

BACKGROUND: The frequency of reactions reported to occur after the consumption of monosodium glutamate (MSG) is the subject of controversy. OBJECTIVE: We conducted a multicenter, multiphase, double-blind, placebo-controlled study with a crossover design to evaluate reactions reportedly caused by MSG. METHODS: In 3 of 4 protocols (A, B, and C), MSG was administered without food. A positive response was scored if the subject reported 2 or more symptoms from a list of 10 symptoms reported to occur after ingestion of MSG-containing foods within 2 hours. In protocol A 130 self-selected reportedly MSG-reactive volunteers were challenged with 5 g of MSG and with placebo on separate days (days 1 and 2). Of the 86 subjects who reacted to MSG, placebo, or both in protocol A, 69 completed protocol B to determine whether the response was consistent and dose dependent. To further examine the consistency and reproducibility of reactions to MSG, 12 of the 19 subjects who responded to 5 g of MSG but not to placebo in both protocols A and B were given, in protocol C, 2 challenges, each consisting of 5 g of MSG versus placebo. RESULTS: Of 130 subjects in protocol A, 50 (38. 5%) responded to MSG only, 17 (13.1%) responded to placebo only (P <. 05), and 19 (14.6%) responded to both. Challenge with increasing doses of MSG in protocol B was associated with increased response rates. Only half (n = 19) of 37 subjects who reacted to 5 g of MSG but not placebo in protocol A reacted similarly in protocol B, suggesting inconsistency in the response. Two of the 19 subjects responded in both challenges to MSG but not placebo in protocol C; however, their symptoms were not reproducible in protocols A through C. These 2 subjects were challenged in protocol D 3 times with placebo and 3 times with 5 g of MSG in the presence of food. Both responded to only one of the MSG challenges in protocol D. CONCLUSION: The results suggest that large doses of MSG given without food may elicit more symptoms than a placebo in individuals who believe that they react adversely to MSG. However, neither persistent nor serious effects from MSG ingestion are observed, and the responses were not consistent on retesting.

Idiopathic anaphylaxis: variants as diagnostic and therapeutic problems.

Idiopathic anaphylaxis presents a problem requiring rapid diagnosis and initiation of therapy. Some cases are complex and difficult to assess. We present four cases of unusual complexity to illustrate diagnostic and therapeutic problems. Two cases were found not to be idiopathic anaphylaxis, one being undifferentiated somatoform idiopathic anaphylaxis and the other very severe urticaria. Various conditions can be or mimic idiopathic anaphylaxis, and patience and observation can result in reasonable outcomes.

Review of alleged reaction to monosodium glutamate and outcome of a multicenter double-blind placebo-controlled study.

Monosodium glutamate (MSG) has a long history of use in foods as a flavor enhancer. In the United States, the Food and Drug Administration has classified MSG as generally recognized as safe (GRAS). Nevertheless, there is an ongoing debate exists concerning whether MSG causes any of the alleged reactions. A complex of symptoms after ingestion of a Chinese meal was first described in 1968. MSG was suggested to trigger these symptoms, which were referred to collectively as Chinese Restaurant Syndrome. Numerous reports, most of them anecdotal, were published after the original observation. Since then, clinical studies have been performed by many groups, with varying degrees of rigor in experimental design ranging from uncontrolled open challenges to double-blind, placebo controlled (DBPC) studies. Challenges in subjects who reported adverse reactions to MSG have included relatively few subjects and have failed to show significant reactions to MSG. Results of surveys and of clinical challenges with MSG in the general population reveal no evidence of untoward effects. We recently conducted a multicenter DBPC challenge study in 130 subjects (the largest to date) to analyze the response of subjects who report symptoms from ingesting MSG. The results suggest that large doses of MSG given without food may elicit more symptoms than a placebo in individuals who believe that they react adversely to MSG. However, the frequency of the responses was low and the responses reported were inconsistent and were not reproducible. The responses were not observed when MSG was given with food.

Hypersensitivity pneumonitis resulting from community exposure to Canada goose droppings: when an external environmental antigen becomes an indoor environmental antigen.

BACKGROUND: In the past, hypersensitivity pneumonitis has been attributed to occupational, agricultural, or home environmental exposure. OBJECTIVE: This report describes the first case of hypersensitivity pneumonitis due to community exposure to droppings from Canada geese migrating through a suburban environment. METHOD: Clinical and serologic information was used in making the diagnosis of hypersensitivity pneumonitis. RESULTS: Serologic analysis demonstrated precipitating antibodies against goose droppings and against an extract made from washings from a filter taken from the patient's office. These studies also showed that the antigens in the office filter were goose dropping antigens. CONCLUSION: Hypersensitivity pneumonitis can result from exposure to goose dropping antigens in the community that enter buildings through ventilation systems. This represents a new form of an old disease.

Idiopathic anaphylaxis.

Anaphylaxis is an acute, life threatening event that can progress extremely rapidly. External allergens as causations have been identified over the last century. The most recently identified type of anaphylaxis is not caused by any external allergen and has been termed Idiopathic Anaphylaxis (IA). Two major types are Generalized or Angioedema with airway obstruction. IA is also classified by frequency of episodes and response to therapy. Therapy consists of acute emergency therapy and induction of remissions using prednisone, beta agonists, and H1 blockers. Control and remission are usually induced. IA occurs at all ages, and pediatric and geriatric IA are often special problems, as is a psychogenic form where no true reactions occur. Although appropriate management of IA, in general, has a good prognosis, several problems exist. Among these are failure to accept IA as an entity or in an individual case by physicians and patients. A different problem occurs when the recommended treatment is used and there is control of IA, but only with persisting high doses of prednisone. This is corticosteroid dependent IA. The lack of defined mechanisms that will lead to improved therapies and wider acceptance of IA as an entity remains a major problem. Undifferentiated Somatoform IA is a serious management problem for physicians.

Rush immunotherapy in a dog with severe ragweed and grass pollen allergy.

BACKGROUND: Forty years of study of naturally occurring IgE-mediated allergy in animals is briefly reviewed. These studies provided models for study of bioactive mediators and innovative pharmacologic therapies for IgE-mediated asthma. OBJECTIVE: Based on our experience with canine allergy we evaluated and treated a dog with severe grass and ragweed allergy whose allergic dermatitis was uncontrolled by H1 blockers and topical corticosteroids. The dog was miserable during the Chicago grass and ragweed pollen seasons. METHODS: Rush immunotherapy was initiated during the ragweed season of 1997. RESULTS: Dramatic improvement was seen which persisted through the grass and ragweed seasons of 1998 after maintenance immunotherapy. CONCLUSION: The case is presented not as a model for canine immunotherapy but as an example of how animal research can be of value to both animals and humans.

Changing patterns in academic allergy-immunology.

In evaluation of the current Allergy-Immunology (AI) Program of the Department of Medicine at Northwestern University Medical School and in planning for the future, it appeared that our assessment of changes in the AI program since its inception might be of value to other AI academic programs. Further, we might receive suggestions from other academic AI programs, and we request such advice.

Concurrent administration of inactivated hepatitis A vaccine with immune globulin in healthy adults.

301 healthy adult volunteers were randomized to one of three treatment groups: inactivated hepatitis A vaccine alone; inactivated hepatitis A vaccine with immune globulin (Ig) concurrently; or Ig alone. The first two treatment groups received a second dose of hepatitis A vaccine at week 24. Anti-HAV was measured 4, 8, 12, 24 and 28 weeks after the primary immunization. When comparing subjects receiving inactivated hepatitis A vaccine alone to those receiving vaccine and Ig, the seropositivity rates were not significantly different at 4, 8, 12 and 28 weeks, but at week 24 the seropositivity rate was lower in the group receiving both vaccine and Ig compared to the group receiving vaccine alone (92.0% compared to 97.0%). At weeks 8, 12 and 24 the geometric mean titers (GMTs) were significantly lower for subjects receiving both vaccine and Ig. The GMTs were not significantly different after the second dose of vaccine. At all time points, the lower serum antibody concentrations observed in subjects receiving both inactivated hepatitis A vaccine and Ig were nevertheless substantially higher than the cutoff for assay seropositivity and much higher than after Ig alone; these differences are therefore clinically insignificant.

Immunoglobulin E antibody against environmental allergens in subjects with trimellitic anhydride-induced asthma.

The purpose of this study was to assess the relationship between atopy and the development of occupational asthma as a consequence of exposure to trimellitic anhydride (TMA). A case-control study was performed, which comprised 16 employees identified as having TMA-induced asthma and 44 similarly exposed controls. Specific immunoglobulin E measurements in response to cat, dust mite, ryegrass, and ragweed antigens were performed. Fifty-six percent of cases and 29% of controls were found to be atopic (P = 0.098). We demonstrated that there was a trend toward employees with TMA asthma being more atopic than those without TMA asthma. Atopy as an assessment of risk for the development of TMA asthma is unlikely to be useful, although further investigation may be warranted.

Potential effect of the administration of substance P and allergen therapy on immunoglobulin E-mediated allergic reactions in human subjects.

Previously we observed and reported that immunoglobulin E-mediated (IgE-mediated) allergy in rhesus monkeys was decreased by the administration of substance P (SP) and an allergen. We extended these studies to human subjects, giving SP and 1 allergen to subjects with reactivity to more than 1 allergen, using reactivity to a second allergen as a control. SP and an allergen were initially given by aerosol delivery but subsequently were given by injection. The administration of SP and 1 allergen by aerosol delivery or injection resulted in decreased IgE-mediated reactivity to the allergen administered and also to the control allergen. This result occurred in 7 of 8 human subjects. The 2 initial subjects receiving 8 SP and allergen injections had a sharp reduction in their symptoms of ragweed hay fever lasting for 3 years to date. No significant reactions to the injection of SP occurred. Further controlled human research is necessary on the administration of SP and allergen and the mechanisms of action. Unexpected and serendipitous results first observed in rhesus monkeys and reproduced in allergic human subjects provide a new and potential mechanism for control and perhaps obliteration of common IgE-mediated allergies and even more-serious allergic problems.

Combination therapy with tirofiban and enoxaparin in acute coronary syndromes.

BACKGROUND: Tirofiban, an intravenous glycoprotein IIb/IIIa antagonist, and enoxaparin, a low molecular weight heparin, have each been shown to be effective at reducing cardiac ischemic events compared to unfractionated heparin alone in separate trials of patients with unstable angina and non-Q-wave myocardial infarction. The combination of these agents may offer further therapeutic benefit. MATERIALS AND METHODS: Fifty-five patients with non-Q-wave myocardial infarction were randomized to receive double-blind treatment with tirofiban (0.1 microgram/kg/min i.v.) for 48-108 h coadministered with either enoxaparin (1 mg/kg sc q 12 h) (n=26) or unfractionated heparin (i.v. adjusted to activated partial-thromboplastin time) (n=27) to evaluate pharmacokinetics, pharmacodynamics, and safety. The primary objective of the study was to investigate the effect of unfractionated heparin versus enoxaparin on the plasma clearance of tirofiban. RESULTS: Coadministration of tirofiban and enoxaparin was generally well tolerated. Plasma clearance of tirofiban was 176.7+/-59.8 and 187.5+/-81.8 ml/min, respectively, for enoxaparin and unfractionated heparin-treated patients (P=NS). The mean difference was well within the prespecified criterion for comparability. Administration of tirofiban with enoxaparin vs. unfractionated heparin resulted in lesser variability and a trend towards greater inhibition of platelet aggregation using 5 microM adenosine phosphate agonist. More patients achieved target inhibition of platelet aggregation >70% in the tirofiban and enoxaparin group (84% vs. 65%, P=0.19). Median bleeding time was 21 min for tirofiban and enoxaparin vs. > or =30 min for tirofiban and unfractionated heparin (P=NS). For a given level of inhibition of platelet aggregation, bleeding time was less prolonged with tirofiban and enoxaparin than tirofiban and unfractionated heparin (adjusted mean bleeding time 19.6 vs. 24.9 min, P=0.02). Tirofiban plasma concentration and clearance were comparable whether coadministered with enoxaparin or unfractionated heparin. There were no major or minor bleeding events in either group by the TIMI criteria. INTERPRETATION: The more consistent inhibition of platelet aggregation and lower adjusted bleeding time of tirofiban and enoxaparin vs. tirofiban and unfractionated heparin support the therapeutic potential of combining these two agents. These data from the first clinical report of coadministration of a glycoprotein IIb/IIIa receptor antagonist and a low molecular weight heparin are consistent with prior data which show differential pharmacodynamic effects of enoxaparin and unfractionated heparin on platelet aggregation.

Hypersensitivity pneumonitis due to humidifier disease: seek and ye shall find.

STUDY OBJECTIVES: This study reports a classic case of hypersensitivity pneumonitis (HP) with classic histologic changes in lung tissue and the research used to identify the causative antigens. DESIGN: A patient with clinical, radiographic, pulmonary function abnormalities and a lung biopsy consistent with HP had no identifiable antigen exposure. SETTING: Evaluation of the patient's activities provided no suggestion of antigen exposure. Her home was evaluated. It was found that her humidifier ran continually without being cleaned but water was added periodically. MEASUREMENTS: Serologic analysis demonstrated precipitating antibodies against her humidifier water and ten antigens in the hypersensitivity lung disease serologic panel. CONCLUSION: Removal of the humidifier, cleaning of the house, and a course of prednisone resulted in the return of the patient to a normal state.