Conclusions
Parietal epithelial cell activation marker is significantly increased in evolving FSGS versus minimal change disease, and this increase may distinguish early FSGS from minimal change disease. Whether parietal epithelial cell activation contributes to pathogenesis of sclerosis in idiopathic FSGS or is a regenerative/repair response to replace injured podocytes awaits additional study.
Results
Cases with early recurrent FSGS manifesting only foot process effacement showed significantly increased CD44+ visceral epithelial cells involving 29.0% versus 2.6% of glomeruli in minimal change disease and 0% in non-FSGS transplants. Parietal location CD44 positivity also was numerically increased in recurrent FSGS. In later transplant biopsies, glomeruli with segmental lesions had more CD44+ visceral epithelial cells than glomeruli without lesions. Conclusions: Parietal epithelial cell activation marker is significantly increased in evolving FSGS versus minimal change disease, and this increase may distinguish early FSGS from minimal change disease. Whether parietal epithelial cell activation contributes to pathogenesis of sclerosis in idiopathic FSGS or is a regenerative/repair response to replace injured podocytes awaits additional study.