Coordinate interaction between IL-13 and epithelial differentiation cluster genes in eosinophilic esophagitis

We have previously proposed that the pathogenesis of eosinophilic esophagitis (EE) is mediated by an IL-13-driven epithelial cell response associated with marked gene dysregulation including eotaxin-3 overproduction. In this study, we compared epithelial responses between healthy patients and those with EE, aiming to uncover molecular explanations for EE pathogenesis. Esophageal epithelial cells could be maintained for up to five passages, with 67% and 62% of cell lines reaching confluence in healthy controls and EE cases, respectively. Both sets of epithelial cells avidly responded to IL-13 at similar levels as assessed by eotaxin-3 production. Acidic pH increased cellular release of eotaxin-3 (4.6 +/- 1.98 ng/ml versus 12.46 +/- 2.90 ng/ml at pH 7.4 and 4, respectively; p < 0.05). Numerous epidermal differentiation complex (EDC) genes, such as filaggrin and SPRR3, were downregulated both in IL-13-stimulated esophageal epithelial cells and in EE biopsies specimens compared with healthy controls. Whereas the filaggrin loss of function mutation 2282del4 was overrepresented in EE compared with control individuals (6.1% versus 1.3% respectively; p = 0.0172), the decreased filaggrin expression was uniformly seen in all EE cases in vivo. Indeed, expression of the EDC genes filaggrin and involucrin was strongly decreased directly by IL-13. These results establish that the epithelial response in EE involves a cooperative interaction between IL-13 and expression of EDC genes.

Interplay of adaptive th2 immunity with eotaxin-3/c-C chemokine receptor 3 in eosinophilic esophagitis

BACKGROUND

Pediatric eosinophilic esophagitis (EE) is a recently described disorder associated with atopy. Although studies of esophageal tissue suggest that Th2 cytokines and eotaxin-3 may be crucial in disease pathogenesis, little is known about the systemic immunological phenotypes of children with EE.

OBJECTIVES

To define the phenotypes of peripheral blood eosinophils and lymphocytes in EE and to examine for correlations between these parameters and tissue eosinophil numbers and disease severity.

PATIENTS AND METHODS

Blood was collected from children with EE, atopic control children without EE, and nonatopic control children without EE. Flow cytometry was used to measure eosinophil expression of chemokine receptor 3 (CCR3) and interleukin-5 receptor-alpha (IL-5Ralpha), and intracellular lymphocyte expression of IL-4, IL-5, IL-13, interferon-gamma, and tumor necrosis factor-alpha. Eosinophil numbers and eotaxin-3 mRNA levels were quantitated in esophageal biopsy specimens.

RESULTS

Compared with nonatopic control children, EE patients with active disease had increased peripheral blood eosinophil percentages, mean channel of fluorescence (MCF) of CCR3 on eosinophils, and percentage of CD4+ T cells expressing IL-5. Notably, these parameters positively correlated with esophageal eosinophil numbers. Eotaxin-3 tissue expression positively correlated with esophageal eosinophil numbers and peripheral blood eosinophil CCR3 MCF. The percentage of peripheral blood eosinophils, eosinophil CCR3 MCF, and CD4+ T cell expression of IL-5 were lower in EE patients in disease remission than in patients with active disease.

CONCLUSIONS

Collectively, these studies demonstrate cooperation between systemic CD4+ Th2-cell-mediated immunity and an enhanced eosinophil-CCR3/eotaxin-3 pathway in EE pathogenesis. Furthermore, the imbalanced Th2 immunity and increased CCR3 expression are reversible with disease remission.

Pediatric patients with eosinophilic esophagitis: An 8-year follow-up

BACKGROUND

Eosinophilic esophagitis (EE) is a gastrointestinal disorder that is increasingly diagnosed in pediatric patients.

OBJECTIVE

We aimed to define, in pediatric patients with EE, their demographic and atopic characteristics, the histopathology of all segments of the gastrointestinal tract, and the effect of therapeutic interventions on the natural history.

METHODS

We conducted a retrospective analysis of a database of pediatric patients with EE followed over a period of 8 years.

RESULTS

In 89 pediatric patients with EE, male sex (78.6%), white race (94.4%), young age at diagnosis, mean +/- SD, 6.2 +/- 4.8 years, and atopy with sensitization to environmental and food allergens in 79% and 75%, respectively, were prevalent. Patients had EE of the proximal and distal esophagus, and 77% had in addition either mucosal eosinophilia or noneosinophilic histopathology in the stomach, duodenum, and colon. EE was chronic, with a duration of mean +/- SD, 0.91 +/- 0.84 years, until first resolution, and was recurrent; of 66% of the patients who had resolution, 79% later relapsed.

CONCLUSION

Eosinophilic esophagitis in the pediatric population is a chronic and relapsing condition, associated with atopy and sometimes with subsequent histopathology in segments of the gastrointestinal tract other than the esophagus.

CLINICAL IMPLICATIONS

Physicians evaluating pediatric patients with chronic gastrointestinal symptoms should consider the diagnosis of EE, particularly in young white male patients with atopy. Once diagnosed and treated, the physicians should follow the patients over a period of several years because the course of the disease is protracted, other gastrointestinal segments may be affected, and relapses are common.

Anti-IL-5 (mepolizumab) therapy for eosinophilic esophagitis

BACKGROUND

Eosinophilic esophagitis (EE) is characterized by high numbers of eosinophils in the esophagus and epithelial hyperplasia, and is being increasingly recognized. IL-5 promotes eosinophil trafficking to the esophagus, and positively regulates eosinophil growth, activation, survival, and tissue recruitment.

OBJECTIVE

We hypothesized that the humanized monoclonal IgG(1) antibody against human IL-5 (mepolizumab) may be useful in the control of EE.

METHODS

An open-label phase I/II safety and efficacy study of anti-IL-5 in 4 adult patients with EE and longstanding dysphagia and esophageal strictures was conducted. Patients received 3 infusions of anti-IL-5 (750 mg intravenously monthly) without change in their current therapy. The levels of plasma IL-5, peripheral blood eosinophils, and CCR3+ cells in blood, quality of life measurements, and histological analysis of esophageal biopsies were determined before and 1 month after treatment.

RESULTS

Peripheral blood eosinophilia and percent of CCR3+ cells decreased by 6.4-fold and 7.9-fold (P < .05), respectively, after anti-IL-5 treatment. Notably, mean and maximal esophageal eosinophilia decreased from 46 to 6 and from 153 to 28 eosinophils/high-power field (x400; average, 8.9-fold, P < .001, and 6-fold, P < .05), respectively. Patients reported a better clinical outcome and improved quality of life (P = .03). Therapy was generally well tolerated, and responsiveness to anti-IL-5 therapy did not correlate with plasma IL-5 levels.

CONCLUSION

Anti-IL-5 therapy is associated with marked decreases in peripheral blood and esophageal eosinophilia (including the number of CCR3+ blood cells) in patients with EE and improved clinical outcomes.

CLINICAL IMPLICATIONS

Anti-IL-5 is a promising therapeutic intervention for EE.

Potential of blood eosinophils, eosinophil-derived neurotoxin, and eotaxin-3 as biomarkers of eosinophilic esophagitis

BACKGROUND & AIMS

Eosinophilic esophagitis (EE) is an increasingly recognized disorder characterized by eosinophilic inflammation of the esophageal mucosa, and typically requires serial invasive endoscopic biopsy examinations to document the characteristic histologic features of the disorder. The aim of this study was to identify noninvasive biomarkers that correlated with disease activity and response to treatment as measured by esophageal eosinophilia.

METHODS

A prospective, cross-sectional analysis was performed on 47 pediatric patients undergoing endoscopic evaluation of possible EE. Blood samples were collected for measurement of peripheral blood absolute eosinophil count (AEC) and levels of eosinophil-derived neurotoxin (EDN), eotaxin-1, -2, and -3, and interleukin-5. Stool samples were collected for measurement of EDN. Biomarker levels were correlated with esophageal eosinophil density, and differences in biomarker levels based on disease activity and treatment were determined.

RESULTS

AEC, plasma EDN levels, and eotaxin-3 levels significantly correlated with esophageal eosinophil density (AEC: r = 0.56, P < .0001; EDN: r = 0.54, P < .0001; eotaxin-3: r = 0.32, P = .04), and were increased in patients with active EE vs controls (AEC: 440 vs 140 eosinophils/muL, P < .05; EDN: 50.3 vs 31.1 ng/mL, P = .01; eotaxin-3: 37.7 vs 11.5 pg/mL, P = .01). Cut-off values were established to maximize the sensitivity, specificity, and predictive values of these biomarkers alone and in combination. Eotaxin-1, eotaxin-2, interleukin-5, and fecal EDN levels did not correlate with esophageal eosinophil density, and were not increased in active EE vs controls or those with inactive EE.

CONCLUSIONS

These data show that blood levels of AEC, EDN, and eotaxin-3 may have value as noninvasive biomarkers for monitoring EE.

A randomized, double-blind, placebo-controlled trial of fluticasone propionate for pediatric eosinophilic esophagitis

BACKGROUND & AIMS

Eosinophilic esophagitis is an increasingly recognized disorder with distinctive endoscopic, histologic, and allergic features. Although several therapies are advocated, no placebo-controlled trials have been conducted. We aimed to determine the efficacy of swallowed fluticasone propionate (FP) in the treatment of eosinophilic esophagitis.

METHODS

We conducted a randomized, double-blind, placebo-controlled trial of swallowed FP in pediatric patients with active eosinophilic esophagitis. Thirty-six patients were randomly assigned to receive either 880 mug of FP (21 patients) or placebo (15 patients) divided twice daily for 3 months. The primary end point was histologic remission, defined by a peak eosinophil count of </=1 eosinophil in all 400x fields in both the proximal and distal esophagus.

RESULTS

Fifty percent of FP-treated patients achieved histologic remission compared with 9% of patients receiving placebo (P = .047). FP decreased esophageal eosinophil levels, with a more pronounced effect in nonallergic individuals (65.9 +/- 25.3 vs 1.4 +/- 1.1 eosinophils/high-power field in the proximal esophagus [P = .03] and 84.6 +/- 19.7 vs 19.6 +/- 12.9 eosinophils/high-power field in the distal esophagus [P = .04]). Resolution of vomiting occurred more frequently with FP than placebo (67% vs 27%; P = .04). FP-induced resolution of mucosal eosinophilia was associated with resolution of endoscopic findings, epithelial hyperplasia, younger age (P = .0003), shorter height (P = .002), and lighter weight (P = .02). Effective treatment with FP decreased the number of CD8(+) T lymphocytes and mast cells in both the proximal and distal esophagus (P < .05).

CONCLUSIONS

Swallowed FP is effective in inducing histologic remission in eosinophilic esophagitis, with a more pronounced effect in nonallergic and younger individuals, especially in the proximal esophagus.