Background: Post-transplant Focal Segmental Glomerulosclerosis (FSGS) is associated with increased risk for renal allograft failure. It has been reported in the literature that podocyte foot process effacement (FPE) may precede FSGS Recurrence in kidney transplant recipients (KTR). There have been only limited data to support that successful management of post-transplant FSGS is associated with resolution of podocyte FPE.

Methods:Patients with a primary diagnosis of FSGS as well as KTR'swith non-biopsy proven primary diagnosis that developed post transplantation proteinuria with evidence of segmental or focal glomerulosclerosis onlight microscopy or diffuse FPE on electron microscopy (EM) were included. The post-transplant FSGS treatment protocol consisted of RTX (total of 2gr over 2 infusions, 2 weeks apart) and monthly cycles of 5 PEX over 7 days for 6 months. Baseline EM results were obtained from renal biopsies performed prior to therapy and Post-treatment FPE was assessed from renal biopsies performed following the completion of treatment. The degree of FPE was categorized into minimal, segmental and extensive.

Results: 10 transplant recipients (8 male) with a mean age of 51 years (range 23-67) were treated for biopsy proven post-transplant FSGS. All patients underwent pretreatment graft biopsies (mean glomeruli per biopsy sampled=20.4+/-11), that included tissue processed for EM. The histology diagnoses included 3 tip lesion 1 collapsing and 2 NOS variants of FSGS, while 3 patients had only podocytopathy, with extensive FPE on EM with an absence of a constituted FSGS lesion. Upon completion of treatment 9/10 KTR's had a biopsy. A resolution of FSGS lesions was found in 4/9 patients, while in 5/9 EM showed improvement in FPE. Histopathology findings correlated to the clinical outcomes, as 9 out of 10 patients achieved remission after the conclusion of treatment (4 complete and 5 partial).

Conclusion: FPE appears to be the earliest histology finding in Post-transplant FSGS. Clinical response to treatment is related to resolution of histopathology lesions and improvement in FPE. Further studies can elucidate the diagnostic and prognostic value of FPE in Post-transplant FSGS.

CITATION INFORMATION: Koutroutsos K, Moss J, Moran L, Cook T, Charif R, Taube D, Roufosse C, Loucaidou M. Treatment of Post-Transplant Focal Glomerulosclerosis: The Effect on Histopathology Lesions and Podocyte Foot Process Effacement. Am J Transplant. 2016;16 (suppl 3).

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