David Dunkin

Skin exposure promotes a Th2-dependent sensitization to peanut allergens

Sensitization to foods often occurs in infancy, without a known prior oral exposure, suggesting that alternative exposure routes contribute to food allergy. Here, we tested the hypothesis that peanut proteins activate innate immune pathways in the skin that promote sensitization. We exposed mice to peanut protein extract on undamaged areas of skin and observed that repeated topical exposure to peanut allergens led to sensitization and anaphylaxis upon rechallenge. In mice, this epicutaneous peanut exposure induced sensitization to the peanut components Ara h 1 and Ara h 2, which is also observed in human peanut allergy. Both crude peanut extract and Ara h 2 alone served as adjuvants, as both induced a bystander sensitization that was similar to that induced by the atopic dermatitis-associated staphylococcal enterotoxin B. In cultured human keratinocytes and in murine skin, peanut extract directly induced cytokine expression. Moreover, topical peanut extract application induced an alteration dependent on the IL-33 receptor ST2 in skin-draining DCs, resulting in Th2 cytokine production from T cells. Together, our data support the hypothesis that peanuts are allergenic due to inherent adjuvant activity and suggest that skin exposure to food allergens contributes to sensitization to foods in early life.

Allergic sensitization can be induced via multiple physiologic routes in an adjuvant-dependent manner

BACKGROUND Oral exposure to food allergens may be limited in infancy, and the initial site of antigen exposure likely plays an important role in food allergy induction. OBJECTIVE To examine the impact of different routes of exposure by using milk allergens, with and without adjuvant, on sensitization. METHODS C3H/HeJ mice were repeatedly exposed to the milk allergen α-lactalbumin (ALA), with or without cholera toxin (CT). Sensitization routes used were intragastric, cutaneous, intranasal, and sublingual. Anaphylaxis severity was assessed by symptoms and body temperature in response to oral challenge. Antigen-specific serum antibodies were measured by ELISA. The mechanism of adjuvant activity of cutaneous CT was also determined. RESULTS Sensitization to ALA as measured by allergen-specific IgE occurred by all routes of sensitization and was maximal in response to cutaneous exposure. Sensitization was dependent on CT and did not occur to antigen alone by any route. Mucosal, but not cutaneous, exposure resulted in a robust allergen-specific IgA response. Anaphylaxis occurred in all sensitized groups when orally challenged with ALA. Topical CT induced migration of langerin(neg) dermal dendritic cells to the lymph node, resulting in enhanced proliferation and T(H)2 cytokine production from responder T cells. CONCLUSIONS Sensitization can occur via all physiologic routes when adjuvant is present. The skin is a potent and likely important physiologic route of sensitization whereby adjuvant induces an efflux of antigen-bearing dermal dendritic cells to the lymph node that generate a proallergic T(H)2 response.

Ganoderic acid C1 isolated from the anti-asthma formula, ASHMI™ suppresses TNF-α production by mouse macrophages and peripheral blood mononuclear cells from asthma patients.

Asthma is a heterogeneous airway inflammatory disease, which is associated with Th2 cytokine-driven inflammation and non-Th2, TNF-α mediated inflammation. Unlike Th2 mediated inflammation, TNF-α mediated asthma inflammation is generally insensitive to inhaled corticosteroids (ICS). ASHMITM, aqueous extract of three medicinal herbs-Ganoderma lucidum (G. lucidum), Sophora flavescens Ait (S. flavescens) and Glycyrrhiza uralensis Fischer (G. uralensis), showed a high safety profile and was clinically beneficial in asthma patients. It also suppresses both Th2 and TNF-α associated inflammation in murine asthma models. We previously determined that G. uralensis flavonoids are the key active compounds responsible for ASHMITM suppression of Th2 mediated inflammation. Until now, there are limited studies on anti-TNF-α compounds presented in ASHMITM. The objective of this study was to isolate and identify TNF-α inhibitory compounds in ASHMITM. Here we report that G. lucidum, but not the other two herbal extracts, S. flavescens or G. uralensis inhibited TNF-α production by murine macrophages; and that the methylene chloride (MC)-triterpenoid-enriched fraction, but not the polysaccharide-enriched fraction, contained the inhibitory compounds. Of the 15 triterpenoids isolated from the MC fraction, only ganoderic acid C1 (GAC1) significantly reduced TNF-α production by murine macrophages (RAW 264.7 cells) and peripheral blood mononuclear cells (PBMCs) from asthma patients. Inhibition was associated with down-regulation of NF-κB expression, and partial suppression of MAPK and AP-1 signaling pathways. Ganoderic acid C1 may have potential for treating TNF-α mediated inflammation in asthma and other inflammatory diseases.

Effect of Antiasthma Simplified Herbal Medicine Intervention on neutrophil predominant airway inflammation in a ragweed sensitized murine asthma model

BACKGROUND Neutrophil-predominant asthma is less responsive to steroids and associated with poorer disease control. The effects of Antiasthma Simplified Herbal Medicine Intervention (ASHMI), a traditional Chinese medicine formula reported to be efficacious in asthmatic patients and murine asthma models, on neutrophil predominant asthma are unknown. OBJECTIVE To determine the effects of standard ASHMI and refined formula ASHMI (ASHMI(II)) in a neutrophil-predominant murine model of ragweed (RW) asthma and explore underlying mechanisms. METHODS BALB/c mice were systemically sensitized, intranasally challenged with RW extract, and orally treated with ASHMI, ASHMI(II), or vehicle (water). In a separate experiment, some RW sensitized mice were treated with dexamethasone before challenge. After RW challenge, airway hyperreactivity (AHR), total and differential bronchoalveolar lavage fluid leukocyte counts, lung histologic features, and bronchoalveolar lavage fluid cytokine and chemokine levels were assessed. RW stimulation of the murine macrophage cell line RAW264.7 was used to determine effects of ASHMI active compound ganoderic acid C1 (GAC1) on tumor necrosis factor α (TNF-α) production and regulation of phosphorylated IκB and histone deacetylase 2 (HDAC2) levels. RESULTS ASHMI and ASHMI(II) markedly reduced AHR, mucous production, neutrophilic inflammation, and TNF-α, interleukin 8, and interleukin 17 levels and decreased eosinophilic inflammation and TH2 responses in vivo (P < .01-.001 for all). GAC1 inhibited TNF-α production in RW-stimulated RAW264.7 cells in association with suppression of phosphorylated IκB and increased HDAC2 expression. Dexamethasone failed to reduce AHR and neutrophilic inflammation. CONCLUSION ASHMI treatment was efficacious in a murine model of neutrophil-predominant asthma via modulation of innate chemokines, TH2 responses, nuclear factor-κB, and HDAC2. ASHMI, and/or its constituent GAC1, may be a valuable option for treating neutrophil-predominant asthma.

Mouse and human Notch-1 regulate mucosal immune responses

The Notch-1 signaling pathway is responsible for homeostatic tight junction expression in vitro, and promotes barrier function in vivo in the RAG1-adoptive transfer model of colitis. In this study, we sought to determine the role of colonic Notch-1 in the lymphoepithelial crosstalk in health and disease. We utilized in vivo and in vitro knockdown to target the expression of Notch-1. We identified that epithelial Notch-1 is required for appropriate activation of intestinal epithelial cells at steady state and upon inflammatory stimulus. Notch-1 expression modulates mucosal chemokine and cytokine secretion, and FoxP3 and effector T-cell responses. We showed that epithelial Notch-1 controls the immune function of the epithelium through crosstalk with the nuclear factor-κB (NF-κB)/mitogen-activated protein kinase (MAPK) pathways that, in turn, elicits T-cell responses. Overall, epithelial Notch-1 bridges innate and adaptive immunity in the gut. Our findings highlight an indispensable role for Notch-1-mediated signaling in the intricate epithelial-immune crosstalk, and validate that epithelial Notch-1 is necessary and sufficient to support protective epithelial proinflammatory responses.

Anti-inflammatory Effects of Ganoderma lucidum Triterpenoid in Human Crohn's Disease Associated with Downregulation of NF-κB Signaling.

Background:Crohns disease (CD) is a chronic inflammatory disease of the gastrointestinal tract. Current medications have potentially serious side effects. Hence, there is increasing interest in alternative therapies. We previously demonstrated the anti-inflammatory effects of Food Allergy Herbal Formula-2 in vitro on peripheral blood mononuclear cells (PBMCs) and mucosa from CD subjects. Here, we investigated the anti-inflammatory effects of a bioactive compound isolated from Ganoderma lucidum (G. lucidum), a key herbal constituent of Food Allergy Herbal Formula-2, in CD in vitro. Methods:Triterpene ganoderic acid C1 (GAC1) was isolated from G. lucidum. Stimulated RAW 264.7 macrophages were treated with GAC1. Human PBMCs and colonic biopsies were obtained from children with CD and cultured with or without GAC1. TNF-&agr; and other proinflammatory cytokine levels were measured in the culture supernatant. NF-&kgr;B signaling was investigated in PBMCs and colonic mucosa treated with GAC1 by In-Cell Western and Western blot analysis. Results:GAC1 decreased TNF-&agr; production by macrophages and PBMCs from CD subjects. GAC1 significantly decreased TNF-&agr;, IFN-&ggr;, and IL-17A production by inflamed colonic biopsies from CD subjects. These effects were due to downregulation of the NF-&kgr;B signaling pathway. Conclusions:GAC1 inhibited production of TNF-&agr; and other proinflammatory cytokines by PBMCs and inflamed CD colonic mucosa due to blockage of NF-&kgr;B activation. GAC1 is a key beneficial constituent in G. lucidum and the Food Allergy Herbal Formula-2 in suppressing the inflammatory cytokines found in CD and warrants clinical investigation for the treatment of CD.

Duodenal and rectal hematomas complicating endoscopic biopsy: use of sonography in pediatrics.

Objective. Intramural duodenal hematomas (IDHs) after nontherapeutic endoscopic biopsy are rare. Rectal hematomas (RHs) have not been reported previously. A review of the literature revealed 18 cases of IDHs. Methods. We reviewed 3 cases that occurred within a 4‐month period at our institution. Results. We report a series of 3 cases occurring within a 4‐month period. In addition, we report a concurrent RH in 1 of these cases. After becoming symptomatic, 2 of these patients had a diagnosis by computed tomography, the third by sonography. All patients had conservative management and were followed with sonography. Conclusions. Sonography was found to be an accurate, safe, and nonionizing way to diagnose and follow hematomas in pediatric patients.

Epicutaneous Tolerance Induction to a Bystander Antigen Abrogates Colitis and Ileitis in Mice

Background: Although inflammatory bowel disease (IBD) is a failure in maintaining tolerance to the intestinal microbiota, few studies have investigated the use of immunologic tolerance as a treatment approach for IBD. We hypothesized that induction of immune tolerance at a distal site could suppress intestinal inflammation through a process of bystander regulation. Methods: Epicutaneous tolerance was induced by topical application of ovalbumin (OVA) using a Viaskin patch for 48 hours. In some experiments, a single feed of ovalbumin was used to drive epicutaneous tolerance-induced regulatory T cells (Tregs) to the intestine. The mechanism of tolerance induction was tested using neutralizing antibodies against TGF-&bgr;, IL-10, and Treg depletion using Foxp3-DTR mice. The capacity of skin-draining Tregs, or epicutaneous tolerance, to prevent or treat experimental IBD was tested using T-cell transfer colitis, dextran sodium sulfate (DSS) colitis, and ileitis in SAMP-YITFc mice. Weight loss, colonic inflammatory cytokines and histology were assessed. Results: Epicutaneous exposure to ovalbumin induced systemic immune tolerance by a TGF-&bgr;-dependent, but IL-10 and iFoxp3+ Treg-independent mechanism. Skin draining Tregs suppressed the development of colitis. Epicutaneous tolerance to a model antigen prevented intestinal inflammation in the dextran sodium sulfate and SAMP-YITFc models and importantly could halt disease in mice already experiencing weight loss in the T-cell transfer model of colitis. This was accompanied by a significant accumulation of LAP+ and Foxp3+ Tregs in the colon. Conclusions: This is the first demonstration that epicutaneous tolerance to a model antigen can lead to bystander suppression of inflammation and prevention of disease progression in preclinical models of IBD.

EBV Status and Thiopurine Use in Pediatric IBD.

Objectives: Epstein Barr virus (EBV) is a human herpes virus that infects 90% of the worlds population and has been linked to the development of lymphoproliferative disorders (LPDs) and immunosuppression. Primary EBV infection in patients with IBD on thiopurines is a risk factor for LPD, including lymphoma. We aimed to describe EBV status in a pediatric population with IBD with an emphasis on those initiating thiopurines. Methods: Electronic medical records and EBV serologies were reviewed and categorized into asymptomatic screening versus suspicion for acute infection. EBV status before therapy was described by sex, age, and therapeutic regimen. Descriptive statistics and univariate analysis were employed. Results: Only 150 (22%) of our 688 pediatric patients with IBD had documented EBV status regardless of age or treatment regimen. Only 17% were assessed for suspicion of acute infection and 83% for screening. Sixty-four (52%) screened patients were checked before starting any treatment and only 40% were immunoglobulin (Ig)G positive. There was no difference in mean age between the seronegative and seropositive group. The majority (63%) of thiopurine-treated patients were IgG negative before starting therapy. Eighty percent of primary EBV infections occurred on thiopurines at a mean (SD) of 2 ± 1.5 years after initiating therapy. Conclusions: The majority of our pediatric patients with IBD with documented EBV status were IgG negative at thiopurine initiation. Thiopurines were also associated with primary EBV infection. EBV status may be an important determinate of whether physicians prescribe thiopurines given the risk of primary EBV infections and lymphoproliferative diseases.

Anti-inflammatory Effects of the Chinese Herbal Formula FAHF-2 in Experimental and Human IBD

Background:Crohns disease (CD) is a chronic inflammatory disease with increasing incidence in children. Current medications have potentially serious side effects, hence increasing interest in alternative therapies. We previously developed an herbal formula, FAHF-2, based on a classical traditional Chinese herbal formula Wu Mei Wan that has long been used in China to treat colitis. We investigated FAHF-2s potential anti-inflammatory effects. Methods:FAHF-2 efficacy was tested in vivo in the CD45RbhiRAG1−/− transfer colitis model. Weight loss, colonic histology, and cytokine production from mesenteric lymph nodes were assessed. Human peripheral blood mononuclear cells (PBMCs) and colonic biopsies were obtained from children newly diagnosed with CD and controls and cultured with or without FAHF-2. Cytokine levels were measured by multiplex immunoassay. The effect of FAHF-2 on TNF-&agr;–producing cells was determined by flow cytometry. NF-&kgr;B signaling was investigated in human lamina propria mononuclear cells upon FAHF-2 treatment by In-Cell Western. Results:FAHF-2–treated mice had decreased weight loss, improved histology, and reduced TNF-&agr;, IL-17, IL-6, and IFN-&ggr; production. In vitro treated PBMCs produced less TNF-&agr;, IFN-&ggr;, and IL-12. FAHF-2 reduced the TNF-&agr;–producing monocytes and T cells. Inflamed CD biopsies produced less TNF-&agr;, IL-17, IL-6, and IL-1&bgr;. These effects are because of decreased NF-&kgr;B activation. Conclusions:FAHF-2 inhibited both adaptive and innate immune proinflammatory cytokine responses in PBMCs and inflamed CD mucosa due in part to blockage of NF-&kgr;B activation. FAHF-2 was effective in halting progression of colitis in a murine model. This study shows that FAHF-2 has potential as a novel treatment of CD.