By pinpointing the location and density of eosinophils, which regulate allergy mechanisms in the immune system, these researchers suggest the disease eosinophilic esophagitis, or EoE, may be under- or misdiagnosed in patients using the current method, which is to take tissue samples (biopsies) with an endoscope.
Despite the limitations of current detection methods for EoE, the study authors say biopsies remain the current standard of care, but the engineers are working toward new diagnostic methods that could be available in five years.
In EoE, eosinophils typically found in the bloodstream invade the esophagus and start chewing away at its lining. Often triggered by food allergies, EoE symptoms overlap with other disorders such as acid reflux.
"The gold standard for understanding this disease is detecting the location and presence of eosinophils in the esophagus. Unfortunately, eosinophils are not uniformly distributed within the esophagus, which can lead to underdiagnosis," says study co-author Leonard Pease. He is also an adjunct professor of gastroenterology and pharmaceutics.
The team showed that even a patient with known EoE would require more than 31 random tissue samples, or biopsies, from an area in the esophagus with low eosinophil density to reliably diagnose EoE. Currently, if a patient is suspected of having EoE, five to 12 biopsies are collected along the esophagus using an endoscope. If more than 15 eosinophils turn up in any one of these samples, a diagnosis of EoE is made.
"This is the first quantitative assessment of how eosinophils are distributed in the esophagus," says co-author Gerald Gleich. "Until now, someone would go in and snip around, but they wouldn't have this map to quantify the degree of infiltration of this disease in relationship to the actual anatomy. These findings impact how many biopsies a doctor should perform."
Since eonsinophils are scattered within the esophagus, EoE can go undetected until severe symptoms surface, ranging from painful swallowing to chest pains that mimic a heart attack.
"This is not the ideal way to diagnose EoE," says Pease. "If the distribution of eosinophils was 100 percent uniform, it wouldn't matter where you sample, but in fact it's patchy. Our mapping shows if you sample in one region, no diagnosis would be made, but if you took another region about an inch away, the same patient would appear to be severely diseased."
MEDICA.de; Source: University of Utah