Crypt apoptotic count reproducibility in small bowel allograft biopsies

Area of Science:

• Gastroenterology
• Transplant Surgery
• Pathology

Background:

• Apoptotic bodies (AB) enumeration is crucial for diagnosing acute cellular rejection (ACR) in small bowel allografts.
• Variability in AB definitions among pathologists may impact diagnostic accuracy.

Purpose of the Study:

• To assess the impact of different apoptotic body (AB) definitions on interobserver and intraobserver agreement in diagnosing acute cellular rejection (ACR) in small bowel allografts.

Main Methods:

• Three pathologists reviewed 30 small bowel allograft biopsies (10 negative, 10 indeterminate, 10 mild ACR) twice.
• Maximal AB count per 10 crypts was recorded under blinded conditions.
• Intraobserver and interobserver agreement were calculated using kappa statistics for both classical and liberal AB definitions.

Main Results:

• Intraobserver kappa values ranged from 0.423 to 0.913, and interobserver kappa values ranged from 0.478 to 0.686.
• Intraobserver diagnostic agreement was 90% with the classical definition and 85% with the liberal definition (P < .01).
• Substantial intraobserver and moderate to substantial interobserver agreement were observed, but diagnostic discrepancies occurred in a subset of cases.

Conclusions:

• While substantial agreement exists for counting apoptotic bodies (AB), variations in definitions can lead to diagnostic discrepancies in acute cellular rejection (ACR) assessment.
• Standardizing AB definitions is recommended to improve diagnostic consistency in small bowel allograft pathology.