Elevated Tryptase in EoE Is an Independent Phenomenon Associated with Extra-Esophageal Symptoms

Eosinophilic esophagitis (EoE) is a chronic disease characterized histologically by > 15 eosinophils per high-power field (eos/hpf). Esophageal mucosal mast cells have been implicated in EoE pathogenesis. The association of atopy with EoE has been established but has not been correlated with levels of serum tryptase. The lack of concurrent atopy in some patients suggests the possibility that atopy may either be the related subtype of EoE or may be a sign of comorbidities. No study has looked at whether patients present with different phenotypes/comorbid disease when they have evidence of elevated serum tryptase. We hypothesized that these patients differ with respect to presentation and comorbidities with more refractory GI disease.

To examine whether elevations of serum tryptase associate with different, more severe clinical presentations in EoE patients which may be explained via mast cell activation.

Retrospective chart review identified 72 patients with EoE with results for serum tryptase between 2015 and 2016. Patients were classified as Tryptase^HI (tryptase > 10.9 µg/l) and Tryptase^LO (< 10.9 µg/l). Clinical characteristics and treatment response were compared using univariate analysis and multivariate regression between the groups.

Out of 72 patients, 12 were tested as Tryptase^HI (16.7%, 95% CI 8.1-25.3%). Tryptase^HI was associated frequently with asthma (P = 0.0003), urticaria (P = 0.002), arthralgia (P = 0.005), sinusitis (P = 0.03), nausea/vomiting (P = 0.046), and eosinophilic gastrointestinal disease (P = 0.001). Asthma and arthralgia were found to be significantly associated with Tryptase^HI (P = 0.0013, P = 0.0098, respectively). Mucosal eosinophil counts and tryptase levels were not correlated (R² 0.095, P = 0.77). Tryptase did not resolve with resolution of esophageal eosinophilia.

We found that EoE patients with elevated tryptase levels more commonly presented with asthma, urticaria, arthralgia, nausea/vomiting, sinusitis, and more distal eosinophilia. This indicates that atopy in EoE patients warrants further exploration. The lack of correlation between histologic remission and reduction of serum tryptase levels post-treatment suggests that mast cell activation may be an independent, yet associated disease. More study into this unique association is warranted.