FOR
PATHOLOGISTS

Recent studies have found that EOSINOPHILIC GASTRITIS AND/OR EOSINOPHILIC DUODENITIS (EG/EoD) may be a COMMON CAUSE OF CHRONIC GASTROINTESTINAL (GI) SYMPTOMS but is often missed.1-4

The consensus threshold for diagnosis of EG/EoD is ≥30 EOSINOPHILS PER HIGH-POWER FIELD (hpf).5-7,a

aIn 5 hpfs in gastric biopsy specimens and/or in 3 hpfs in duodenal biopsy specimens.1,5,7

SYSTEMATIC COUNTING OF TISSUE EOSINOPHILS UNDER HIGH-POWER MAGNIFICATION IS KEY TO DETECTION OF EG/EoD2,5-8

Low-power magnification (100×)
Gastric body specimen

A cursory low-power examination can give the false impression that there are few eosinophils present 7,9

High-power magnification (400×)
Gastric body specimen

Careful inspection of the specimen under high-power magnification may reveal a high quantity of eosinophils 1,5,6,8

EG/EoD can be easily missed during standard histopathology evaluation2

Many patients with EG/EoD have no histologic morphology abnormalities other than increased eosinophils in gastric and duodenal biopsy specimens10

Tissue eosinophilia is highly patchy in EG/EoD, so it is important to evaluate multiple hpfs in each biopsy specimen6

4-STEP METHOD FOR EVALUATING BIOPSY SPECIMENS FOR EG/EoDb

Method used by leading pathologists in clinical studies of EG/EoD to evaluate standard hematoxylin and eosin (H&E)-stained sections from gastric and duodenal biopsy specimens.

Research on optimizing the detection of EG/EoD continues to evolve, and each healthcare provider should determine the method that is appropriate for their individual patient cases11

Download the histopathology method and review the full details below

bAllakos does not provide medical advice and assumes no liability for medical care decisions made using this approach. Medical care decisions for individual patients are to be made by patients’ healthcare professionals, including decisions regarding diagnosing EG/EoD and how to evaluate biopsy samples.

RULING OUT OTHER CAUSES

LOW-POWER MAGNIFICATION
(40× AND 100×)

  • Initial exam to evaluate for proper orientation and to rule out the presence of lesions suggestive of other causes (eg, H. pylori infection, celiac disease, neoplasia)12-14

SELECTING AREAS OF HIGHEST EOSINOPHIL DENSITY

MEDIUM-POWER MAGNIFICATION
(200×)

  • Identification of areas with the highest eosinophil density1,5,12
  • Morphologic abnormalities other than increased eosinophils are absent in many EG/EoD specimens and do not reliably identify areas of high eosinophil density9

COUNTING EOSINOPHILS PER HPF

HIGH-POWER MAGNIFICATION
(400×)

  • Quantification of the number of eosinophils per hpf (0.237 mm2) in at least 5 nonoverlapping hpfs per biopsy specimen5,12,14
  • Use of a systematic approach to counting, including utilization of a simple counting device15

REPORTING EOSINOPHIL COUNT IF ≥30 PER HPF

Inclusion of the following items in the pathology report to the requesting physician:

  • Notification if there are ≥30 eosinophils per hpf in 5 hpfs in gastric biopsy specimens and/or ≥30 eosinophils per hpf in 3 hpfs in duodenal biopsy specimens1,5-7
  • Comment indicating whether findings are consistent with EG/EoD

ADDITIONAL CONSIDERATIONS FOR EVALUATING BIOPSY SPECIMENSc

PATCHINESS OF EOSINOPHILIA

Eosinophilic infiltration is often highly patchy across different areas of the same specimen, which suggests selecting fields with the highest eosinophil density may improve detection6

Gastric body specimen
Two areas within the same specimen
Low-power magnification (40×)

Area #1 from gastric body specimen
Fewer than 10 eosinophils per hpf
Medium-power magnification (200x)

Area #2 from gastric body specimen
More than 100 eosinophils per hpf
Medium-power magnification (200x)

SYSTEMATIC COUNTING APPROACH

A systematic approach to counting eosinophils per hpf as well as a simple mechanical counter device were used in EG/EoD studies15

“Lawnmower” approach
Scanning up one column and down the next, repeating across the field

“Quadrant” approach
Scanning the field in a conventional order, such as from left to right

“Spiral” approach
Scanning the field in a spiral fashion, either inward or outward

cRepresentative images of biopsy specimens from patients diagnosed with EG/EoD.

Robert Genta, MD and Kevin Turner, MD: GI PATHOLOGY EXPERTS

A systematic approach to counting eosinophils under high-power magnification may help avoid missed cases of EG/EoD

PHYSICIAN PERSPECTIVE:
DR ROBERT GENTA AND DR KEVIN TURNER EXAMINE THE HISTOPATHOLOGY METHOD FOR DIAGNOSING EG/EoD USED IN RECENT EG/EoD STUDIES

A systematic approach to counting of eosinophils in multiple hpfs
can increase detection of EG/EoD1,2,7

These healthcare professionals serve as disease education speakers for Allakos to help share EG/EoD insights like those in these videos, in addition to performing other services for the company. They receive compensation for this work.

Hear from leading
GI pathologists
Robert Genta, MD, FACG
Kevin Turner, DO

EG/EoD WAS FOUND TO BE MUCH MORE COMMON THAN PREVIOUSLY THOUGHT WHEN PATIENTS WERE EVALUATED USING SYSTEMATIC BIOPSY AND HISTOPATHOLOGY METHODS1

References: 1. Talley NJ, Kamboj AP, Chey WD, et al. Endoscopy and systematic biopsy of patients with chronic gastrointestinal symptoms leads to high discovery rate of patients who meet histologic criteria for eosinophilic gastritis and/or eosinophilic duodenitis. Presented at: Digestive Disease Week Virtual; May 22, 2021.  2. Chehade M, Kamboj AP, Atkins D, Gehman LT. Diagnostic delay in patients with eosinophilic gastritis and/or duodenitis: a population-based study. J Allergy Clin Immunol Pract. 2021;9(5):2050-2059.e20. doi:10.1016/j.jaip.2020.12.054.  3. Licari A, Votto M, Scudeller L, et al. Epidemiology of nonesophageal eosinophilic gastrointestinal diseases in symptomatic patients: a systematic review and meta-analysis. J Allergy Clin Immunol Pract2020;8(6):1994-2003.e2. doi:10.1016/j.jaip.2020.01.060.  4. Alhmoud T, Hanson JA, Parasher G. Eosinophilic gastroenteritis: an underdiagnosed condition. Dig Dis Sci2016;61(9):2585-2592. doi:10.1007/s10620-016-4203-5.  5. Dellon ES, Peterson KA, Murray JA, et al. Monoclonal antibody for eosinophilic gastritis and duodenitis. N Engl J Med. 2020;383(17):1624-1634. doi:10.1056/NEJMoa2012047.  6. Gonsalves N. Eosinophilic gastrointestinal disorders. Clin Rev Allergy Immunol2019;57(2):272-285. doi:10.1007/s12016-019-08732-1.  7. Dellon ES, Gonsalves N, Rothenberg ME, et al. Determination of biopsy yield that optimally detects eosinophilic gastritis and/or duodenitis in a randomized trial. Clin Gastroenterol Hepatol. 2021;S1542-3565(21)00592-9. doi:10.1016/j.cgh.2021.05.053.  8. Egan M, Furuta GT. Eosinophilic gastrointestinal diseases beyond eosinophilic esophagitis. Ann Allergy Asthma Immunol2018;121(2):162-167. doi:10.1016/j.anai.2018.06.013.  9. Hirano I, Chehade M, Gonsalves N, et al. Endoscopic appearance does not predict the presence of histologic eosinophil gastritis among symptomatic adults, indicating that collection and evaluation of biopsies should occur regardless of endoscopic appearance: analysis from a randomized trial. Poster presented at: Digestive Disease Week Virtual; May 21, 2021.  10. Reed C, Woosley JT, Dellon ES. Clinical characteristics, treatment outcomes, and resource utilization in children and adults with eosinophilic gastroenteritis. Dig Liver Dis2015;47(3):197-201. doi:10.1016/j.dld.2014.11.009.  11. Dellon ES, Peterson KA, Murray JA, et al. Monoclonal antibody for eosinophilic gastritis and duodenitis [supplemental appendix]. N Engl J Med. 2020;383(17):1-29. doi:10.1056/NEJMoa2012047.  12. Dellon ES, Peterson KA, Murray JA, et al. Monoclonal antibody for eosinophilic gastritis and duodenitis [trial protocol]. N Engl J Med. 2020;383(17):1-266. doi:10.1056/NEJMoa2012047.  13. Lwin T, Melton SD, Genta RM. Eosinophilic gastritis: histopathological characterization and quantification of the normal gastric eosinophil content. Mod Pathol2011;24(4):556-563. doi:10.1038/modpathol.2010.221.  14. Genta RM, Sonnenberg A, Turner K. Quantification of the duodenal eosinophil content in adults: a necessary step for an evidence-based diagnosis of duodenal eosinophilia. Aliment Pharmacol Ther2018;47(8):1143-1150. doi:10.1111/apt.14558.  15. Data on File, Systematic Eosinophil Counting Techniques. Allakos Inc.