High Discordance Rate in Lung Transplant Rejection Grading: A Review of 414 Transbronchial Surveillance Biopsies
KJ Henriksen, K Suzue, S Bhorade, E Garrity, AN Husain. The University of Chicago, Chicago, IL
Background: Transbronchial biopsies are routinely performed in lung transplant recipients to assess for rejection, and are graded according to a standardized schema established by The International Society for Heart and Lung Transplantation (ISHLT). Acute rejection is characterized by perivascular inflammation, and is graded according to severity from Grade A0 to A4. Airway rejection, or lymphocytic bronchiolitis, is manifested by inflammatory infiltration of the small airways, and is similarly graded from Grade B0 to B4. We assessed the concordance rates between independent pathologists' readings of transbronchial biopsies obtained from patients enrolled in a large multicenter randomized trial.
Design: Transbronchial biopsies were obtained at 6 weeks, 3, 6 and 12 months post-lung transplant from 181 patients enrolled in 7 U.S. transplant centers in the AIRSAC study. A total of 414 surveillance biopsies were obtained. The biopsies were read at each center by various pathologists utilizing the ISHLT 1996 grading criteria. The biopsies were then re-graded by one central pathologist blinded to the original reading.
Results: Of 310 biopsies considered sufficient for Grade A rejection, 60% (186) were graded similarly by two independent pathologists. Of those graded differently, 69% (87) differed by one grade and 31% (39) differed by two grades. 76 of 87 (87%) and 37 of 39 (95%) were downgraded by the central pathologist, respectively. Of the 141 biopsies sufficient for Grade B rejection, 70% (99) were graded similarly by the two independent pathologists. Of those graded differently, 76% (32) differed by one grade and 24% (10) differed by two grades. 24 of 32 (75%) and 10 of 10 (100%) were downgraded by the central pathologist, respectively.
Conclusions: In this study, there was a high discordance rate among pathologists' interpretations of lung transplant biopsies. These results suggest that consistency and experience may be enhanced by designating a single pathologist to interpret lung transplant biopsies in each center. The study also emphasizes the importance of recognizing bronchial associated lymphoid tissue (BALT), which is often hyperplastic. Failure to recognize BALT can lead to an over-diagnosis of acute rejection.
Monday, March 9, 2009 1:00 PM
Poster Session II # 238, Monday Afternoon