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.

Extrinsic allergic alveolitis from a proteolytic enzyme.

BACKGROUND: Subtilisins are proteolytic enzymes of bacterial origin found in detergents. They are high-molecular-weight antigens and have been implicated in allergic rhinitis and asthma. OBJECTIVE: This report describes a case of extrinsic allergic alveolitis due to subtilisins in a liquid cleaner. METHODS: Clinical, radiologic, and serologic information were used to make the diagnosis. CASE REPORT: A 53-year-old woman developed respiratory symptoms while working with a cleaner containing subtilisins. Her symptoms intensified in the work environment and improved away from work. A computed tomography scan demonstrated alveolar and interstitial infiltrates with subsequent scarring. A pulmonary function study revealed a restrictive pattern with diminished diffusion capacity. Bronchoalveolar lavage showed lymphocytosis and all cultures were negative. Precipitating antibodies to the enzyme were found in the patient's serum. Her symptoms improved once she changed her occupation. CONCLUSIONS: The combination of the patient's clinical history, physical, laboratory, and radiologic findings support the diagnosis of extrinsic allergic alveolitis from the enzyme contained in the cleaner.

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.

Case reports of evaluation and desensitization for anti-thymocyte globulin hypersensitivity.

BACKGROUND: Biologic products of heterologous sera have been used to treat a variety of conditions. One example is anti-thymocyte globulin (ATG), which is approved for use in the management of renal transplantation and for aplastic anemia. As ATG is a product of heterologous sera it has the potential for adverse reactions, including anaphylaxis. Patients can be skin tested prior to ATG administration to aid in determining hypersensitivity status to ATG. OBJECTIVE: To provide case reports to illustrate evaluation for ATG hypersensitivity. Also, to discuss desensitization procedures for patients who are found to have ATG hypersensitivity, and yet are to receive the medication as it is judged to be essential. CASE REPORTS: We report four patients who were to receive ATG. The results of skin testing and each patient's response to ATG are reviewed to illustrate problems that can occur in evaluating the hypersensitivity status of these patients. Further, some patients also underwent ATG desensitization, but none completed the entire protocol successfully. Their outcomes are reviewed to illustrate problems that can occur with the desensitization procedure. CONCLUSION: Anti-thymocyte globulin is a product of heterologous sera and has the potential to produce anaphylaxis. It is recommended that patients be skin tested prior to administration to aid in determining hypersensitivity status. Those patients who demonstrate hypersensitivity to ATG should not receive ATG unless it is deemed essential and benefits are judged to outweigh risks. In these circumstances, patients are candidates for ATG desensitization. Complications with desensitization occurred in the cases attempted, and highlights that desensitization to ATG, a xenogeneic protein, carries risk and can be difficult. Physicians involved in such cases should be familiar with interpretation of skin tests and problems that can occur with desensitization.

Human leucocyte antigens (HLA) and trimellitic anhydride (TMA) immunological lung disease.

Occupational immunological lung disease, due to low molecular weight, reactive chemicals such as trimellitic anhydride (TMA), is an emerging health problem. If there were a marker that was highly predictive of the ability of the immune system to recognize TMA as an allergen, better prevention strategies could be employed with at risk individuals. The purpose of this study is to evaluate whether human leucocyte antigen (HLA) class specificity is associated with the development of late respiratory systemic syndrome (LRSS) or asthma due to immunological sensitivity to trimellitic anhydride (TMA). This is a case control study of 17 individuals with LRSS, 12 with asthma and 22 TMA similarly exposed individuals who did not develop LRSS or asthma. Comparing the sensitized individuals (LRSS or asthma) with the non-sensitized individuals (controls), we found no difference in frequency of any HLA antigen. In summary, the lack of association of HLA antigens with LRSS or asthma due to TMA suggests that these will not be useful markers to identify at risk individuals.

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.

Corticosteroid therapy in an additional 13 cases of Stevens-Johnson syndrome: a total series of 67 cases.

Stevens-Johnson syndrome (SJS) is a severe cutaneous eruption that can be a life-threatening emergency. Previously, we have reported our favorable experience in treating 54 patients with SJS with systemic corticosteroids. We continued our prospective analysis of consecutive patients with SJS treated with corticosteroids. Possible etiologic factors and clinical outcomes of the patients are described. All 13 patients improved with initiation of systemic corticosteroid therapy. There was no mortality or permanent sequelae attributable to SJS. Drugs were the offending agents in all 13 cases. There was one death unrelated to SJS. In conclusion, prompt treatment with systemic corticosteroids reduces morbidity and improves outcome of SJS patients. This analysis extends our series to 67 consecutive patients with SJS who were treated with corticosteroids and had a favorable outcome.

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.

Clinical and immunologic outcome of 42 individuals with trimellitic anhydride-induced immunologic lung disease after transfer to low exposure.

The purpose of this study is to determine the clinical and immunologic status of trimellitic anhydride (TMA)-exposed employees who have had immunologic lung disease and who have been moved to lower-exposure jobs. In a case series design, 42 consecutive employees with TMA-induced immunologic lung disease were studied after they had been moved to low-exposure jobs for more than 1 year. Pulmonary symptoms were obtained by physician-administered questionnaire. Immunologic studies were performed using ELISA techniques. Spirometry and chest films were obtained annually. Employees with late asthma (n = 4), late respiratory systemic syndrome (LRSS) (n = 13), or both LRSS and asthma (n = 4) had improved symptoms, improved pulmonary functions, and lower IgE against TM-HSA. Fourteen of 21 employees with asthma had improved symptoms, improved pulmonary functions, and lower IgE against TM-HSA. The 7 who did not improve with transfer to low-exposure jobs did improve with transfer to jobs with no TMA exposure. There were no chest film findings in any group that were definitely related to TMA. Most individuals who develop TMA hypersensitivity syndromes improve with transfer to low- exposure jobs, but occasionally, individuals require transfer to a no-exposure job.

A clinical and immunologic study to assess risk of TMA-induced lung disease as related to exposure.

The objective of this study was to determine whether there are trimellitic anhydride (TMA) exposure levels that are very unlikely to cause immunologically mediated respiratory disease. A 3-year clinical and immunologic survey study of 286 employees was conducted at a facility that manufactures TMA. Each employee was assigned an exposure classification from 1 (highest) to 5 (lowest). Of the 28 individuals in exposure class 1, 8 (29%) developed disease; of the 57 class 2 employees, 2 (4%) developed disease; of the 79 class 3 employees, 4 (5%) developed disease. Of the 98 class 4 employees and the 24 class 5 employees, none developed disease. Inasmuch as individuals in class 4 and 5 (TMA exposure < 0.002 mg/m3) are at low risk of developing disease due to TMA, it appears that they do not warrant routine inclusion in surveillance studies.

Pharmacotherapy to prevent the complications of allergic rhinitis.

Allergic rhinitis is an immunologic disease with effects that extend beyond the symptoms that occur subsequent to allergen exposure. A reduced quality of life and medical conditions such as asthma, sinusitis and otitis media are well recognized complications of allergic rhinitis. Craniofacial abnormalities, nasal ployps, and respiratory infections have been linked to allergic rhinitis, but the evidence is conflicting. This article reviews the complications of allergic rhinitis, their prevalences, possible mechanisms for their relationship to allergic rhinitis, and the prevention of these complications via pharmacologic treatment of allergic rhinitis.

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.

Allergen immunotherapy: a long-term perspective.

Efficacy of standard IT to reduce medications and symptoms by at least 50% has been demonstrated multiple times. Reports of negative studies of IT deserve only evaluation of why the study design failed to demonstrate efficacy. Emphasis in the US and worldwide should be on education on the appropriate use of allergen IT, improvements in IT therapy, and preparation for the increased demand for allergists-immunologists as Fellowship training programs decline in numbers and individual training slots decrease.

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.