The Significance of Podocyte Foot Process Effacement (FPE) in Primary IGA Nephropathy: Clinicopathologic Study of 161 Cases
SG Sharma, N Gokden. University of Arkansas for Medical Sciences, Little Rock, AR
Background: IGA nephropathy (IGAN) is the most common glomerular disease worldwide. Patients may present with hematuria and non-nephrotic (NNRP) or uncommonly nephrotic range proteinuria (NRP). To our knowledge, correlation of podocyte FPE with subclasses of IGAN and proteinuria (PT) has not been studied.
Design: Retrospectively, 161 cases of primary IGAN with light, immunofluorescence and electron microscopy (EM) were reviewed and classified according to HAAS classification. EM was available in 110/161 (67%) cases. FPE was evaluated as mild:<30%, moderate:30-70%, severe:>70% and correlated with class and the level of PT.
Results: 101 were males and 60 were females with M: F ratio of 1.71: 1. In 72 cases, race was known as follows: White: 63(88%); black: 6(8%); Hispanic: 2(3%); Asian:1(1%).Clinical history was available in 94 cases: PT 39 cases (42%), PT+hematuria 33 cases(35%), hematuria 15 cases(16%), and renal failure in 7 cases(7%). In 88 cases with FPE, PT was nephrotic in 21 and non-nephrotic in 29 cases. The distribution of cases in different HAAS class in relation to the EM findings, FPE and PT are shown in Table 1.
Table 1. The distribution of cases.Mod:moderate, sev:severe.
|HAAS class||# of cases=161||EM + deposits n=88/110||FPE n=88/110||proteinuria-NRP=21, NNRP=29 cases|
|I||44||25/27||mild-10/27 Mod-3/27 sev-7/27 n=20/27 (74%)||NRP-3(1mod,2sev FPE;NNRP-9(5mild,4sev FPE)|
|II||59||40/43||mild-14/43 mod-4/43 sev-17/43 n=35/43 (81%)||NRP-9(5mild,4sev FPE);NNRP-12(6mild,2mod,4sev FPE)|
|III||34||23/23||mild-9/23 mod-3/23 sev-8/23 n=20/23 (87%)||NRP-5(1mild,4sev FPE);NNRP-6(2mild,2mod,2sev FPE)|
|IV||6||5/5||mild-1/5 mod-0/5 sev-2/5 n=3/5 (60%)||NRP-1(1sev FPE);NNRP-0|
|V||18||12/12||mild-3/12 mod-1/12 sev-6/12 n=10/12 (83%)||NRP-3(3sevFPE);NNRP-2(1mild,1sev FPE)|
Conclusions: FPE is common in IGAN. No correlation between FPE and NRP or NNRP group, or IGAN subclass is present. Whether FPE is simply a reflection of other pathologic mechanisms and its significance in the pathophysiology of IGAN requires further investigation.
Monday, March 9, 2009 1:00 PM
Poster Session II # 249, Monday Afternoon