Tryptase staining of mast cells may differentiate eosinophilic esophagitis from gastroesophageal reflux disease.
OBJECTIVE
Mast cells may contribute to the pathogenesis of eosinophilic esophagitis (EoE), but their role in diagnosis is unknown. Our aim was to determine whether tryptase staining of esophageal mast cells differentiates EoE from gastroesophageal reflux disease (GERD) and has utility for diagnosis of EoE.


METHODS
We performed a case-control study comparing patients with EoE, defined by consensus guidelines, to GERD patients with eosinophils on esophageal biopsy. Immunohistochemistry was performed with mast cell tryptase. The density (mast cells/mm2) and intensity (0-4 scale) of mast cell staining was compared between groups after masking the diagnosis. Receiver operating characteristic (ROC) curves were constructed, and the area under the curve (AUC) was calculated to assess mast cell staining as both a stand-alone diagnostic test and an adjunctive assay with eosinophil counts.


RESULTS
Fifty-four EoE (mean age 24 years; 69% male; mean 146 eosinophils per high-power field (eos/hpf)) and 55 GERD (mean age 34 years; 60% male; mean 20 eos/hpf) patients were analyzed. The maximum epithelial tryptase density was higher in EoE than in GERD (162±87 mast cells/mm2 vs. 67±54; P<0.001). Mast cells were diffusely distributed throughout the biopsy in more EoE than GERD patients (41 vs. 7%; P<0.001). Tryptase density and eosinophil count were only weakly correlated (R2=0.09; P=0.002). The AUC was 0.84 for tryptase staining alone, and 0.96 for the combination of mast cells and eosinophils.


CONCLUSIONS
Patients with EoE have higher levels of tryptase-positive mast cells compared with GERD patients, improving the diagnostic value of biopsies beyond eosinophil counts alone. Mast cell tryptase may have utility as a diagnostic assay for EoE.
Division of Gastroenterology and Hepatology, Department of Medicine, Center for Esophageal Diseases and Swallowing, University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599-7080, USA. edellon@med.unc.edu
Evan S
ES
Dellon
Xiaoxin
X
Chen
C Ryan
CR
Miller
Karen J
KJ
Fritchie
Tara C
TC
Rubinas
John T
JT
Woosley
Nicholas J
NJ
Shaheen
D000328:Adult; D019540:Area Under Curve; D001706:Biopsy; D016022:Case-Control Studies; D016009:Chi-Square Distribution; D057765:Eosinophilic Esophagitis / Q000175:diagnosis* / Q000201:enzymology*; D005260:Female; D005764:Gastroesophageal Reflux / Q000175:diagnosis* / Q000201:enzymology*; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008407:Mast Cells / Q000201:enzymology*; D012372:ROC Curve; D053802:Tryptases / Q000378:metabolism*
D053802:Tryptases