Clinicopathological Analysis of Collapsing Focal Segmental Glomerulosclerosis after Kidney Transplantation.

Introduction: There is limited evidence regarding collapsing focal segmental glomerulosclerosis (cFSGS) after kidney transplantation. The aim of this study was to clarify the clinicopathological character of cFSGS.

Methods: Forty-two biopsies from 35 patients with cFSGS were included in the study. The cFSGS variant was determined according to the Colombia classification. The scoring of arteriosclerosis was evaluated as a score of 0-3 on the basis of the intimal fibrous thickening divided by the media, and other histological scoring was evaluated using the Banff score. Biopsies with a sclerosis score ≥3/4 were excluded from the study. Multivariate analysis was performed by a forward selection method using covariates significantly associated with cFSGS biopsies.

Results: Of 42 biopsies diagnosed with FSGS, 19 (45.2%) biopsies were cFSGS and 23 (54.8%) were non-collapsing FSGS (ncFSGS). The cFSGS group had a longer time after transplantation, lower eGFR, higher urine protein levels, and higher systolic blood pressure (all statistically significant) compared with the ncFSGS group. The Banff aah, ci, and arteriosclerosis scores were significantly higher in the cFSGS group compared with the ncFSGS group. There were no significant differences in the donor age or arteriosclerosis in 1-h biopsies between groups. Multivariate analysis showed that the arteriosclerosis score and Banff ci score were significantly associated with cFSGS using covariates that were statistically significant-related factors including systolic blood pressure, eGFR, proteinuria, ci score, aah score, and arteriosclerosis score. Graft survival after the time of biopsy was significantly worse in the cFSGS group compared with the ncFSGS group.

Conclusion: Collapsing FSGS was poor prognostic factor for allograft survival. Arteriosclerosis and chronic interstitial fibrosis may be related to cFSGS after kidney transplantation.