Interobserver variability in grading transbronchial lung biopsy specimens after lung transplantation

Area of Science:

• Transplantation immunology
• Pulmonary pathology
• Graft rejection diagnostics

Background:

• Acute rejection is a primary cause of morbidity following lung transplantation.
• An international grading system exists to standardize acute lung allograft rejection diagnosis.
• Previous studies have not sufficiently assessed the reliability of this grading system.

Purpose of the Study:

• To evaluate the interobserver agreement in grading transbronchial biopsy specimens for acute lung allograft rejection.
• To assess the reliability of the international grading system in a multicenter setting.

Main Methods:

• Analysis of 481 transbronchial biopsy specimens from the AIRSAC multicenter trial.
• Grading by both site and central pathologists for acute rejection and lymphocytic bronchiolitis.
• Interobserver reliability assessed using Cohen κ coefficients.

Main Results:

• Overall concordance rates were 74% for grade A and 89% for grade B biopsy specimens.
• Agreement was higher early (≤ 6 weeks) post-transplant compared to later time points.
• Moderate agreement was observed for both grade A (κ=0.479) and grade B (κ=0.465) rejection.

Conclusions:

• Results confirm significant interobserver variability in grading lung transplant biopsy specimens.
• Further education on histopathologic findings is recommended for lung transplant pathologists.
• Revisiting current grading criteria is suggested to enhance concordance in diagnosing acute lung allograft rejection.