Changes in IgG4 and IL-10 expression in adults with eosinophilic
esophagitis on a two-food elimination diet
Background: Eosinophilic esophagitis (EoE) is increasingly
diagnosed in patients with dysphagia and upper gastroenteric symptoms.
Elimination diets and/or pharmacologic agents may accomplish temporary
remission, but long-term control is challenging. Type-2 immunity to
ingested antigens can induce EoE histopathology via non-IgE-dependent
mechanisms, possibly involving IgG4 and IL-10 production. To elucidate
the contribution of IgG4- and IL-10-producing cells to EoE pathogenesis,
we examined their frequencies and association with clinical and
histologic endpoints in adult EoE patients given a two-food elimination
diet (TFED). Methods: Sixteen patients with EoE were prescribed
a TFED. Biopsies collected at baseline and follow-up were used for
immunofluorescent detection of IgG4- and IL-10-expressing cells and
serum food-specific IgG4 were measured. All variables were correlated
with established histologic measures of disease activity.
Results: Patients exhibited significant clinical improvement
and significant reduction in esophageal eosinophilia and overall
histology. A significant decrease in the frequencies of IL-10-expressing
cells was also observed, which correlated with histologic changes. In
contrast, a concomitant decline in serum and esophageal IgG4, while
substantial, did not correlate with IL-10 +-cell
frequencies or any histologic parameter of EoE activity.
Conclusions: The close association of esophageal IL-10
expression with histologic features and their changes after a TFED
suggests a critical role of this cytokine in EoE pathogenesis.
Conversely, IgG4 serum and mucosal expression, while reflecting the
level of exposure to relevant food antigens, is not obviously related to
EoE histopathology or IL-10 expression. Studies are needed to
characterize IL-10 cellular sources and their functions in EoE
progression and treatment response.