title: Focal segmental glomerulosclerosis plays a major role in the progression of IgA nephropathy. II. Light microscopic and clinical studies.
abstract: It is well known that lesions morphologically identical with focal segmental glomerulosclerosis (FSGS) may appear in IgA nephropathy (IgAN). Capsular adhesions without underlying abnormalities in the tuft, often the first sign of FSGS, are frequent in IgAN. In this retrospective study, a new cohort of 128 adult patients with IgAN was used to validate the new Oxford classification system of IgAN, and shown to have highly significant associations with clinical and outcome parameters. We then used these patients to determine the extent to which IgAN could be accounted for in terms of FSGS. Some form of lesion consistent with FSGS, notably hyalinosis and collapsing glomerulopathy, was found in 101 of these patients. No glomerular lesions were found in 16 patients, and 11 had mild lesions not definable as FSGS. Those with FSGS had significantly worse renal survival at 80 months than those without. Comparison of pure forms of FSGS (excluding collapsing glomerulopathy) with cases of FSGS having other glomerular lesions (mesangial hyperplasia, endocapillary hypercellularity, glomerular necroses, extracapillary proliferation) revealed that those with FSGS and other superimposed lesions did significantly worse than cases of pure FSGS at 80 months following diagnosis. Importantly, patients with pure FSGS had relatively poor survival even without other superimposed glomerular abnormalities. Thus, the majority of cases of IgAN can be interpreted as representing one or another variant of FSGS. Hence, interpreting IgAN in terms of FSGS emphasizes the role that podocyte lesions may play in the pathogenesis and progression of this disease.
authors.affiliation: Department of Pathology, Hôpital Européen Georges Pompidou, Paris, France; INSERM U845, Hôpital Necker-Enfants Malades, Paris, France.
authors.forename: Khalil
authors.initials: K
authors.lastname: El Karoui
authors.affiliation: Department of Pathology, Hôpital Européen Georges Pompidou, Paris, France. Electronic address: garyhillparis@aol.com.
authors.forename: Gary S
authors.initials: GS
authors.lastname: Hill
authors.affiliation: Department of Nephrology, Hôpital Européen Georges Pompidou, Paris, France.
authors.forename: Alexandre
authors.initials: A
authors.lastname: Karras
authors.affiliation: Department of Nephrology, Hôpital Ambroise Paré, Boulogne Billancourt, France.
authors.forename: Luc
authors.initials: L
authors.lastname: Moulonguet
authors.affiliation: Department of Nephrology, Hôpital Sud Francilien, Evry, France.
authors.forename: Valérie
authors.initials: V
authors.lastname: Caudwell
authors.affiliation: Department of Pathology, Hôpital Européen Georges Pompidou, Paris, France.
authors.forename: Alexandre
authors.initials: A
authors.lastname: Loupy
authors.affiliation: Department of Pathology, Hôpital Européen Georges Pompidou, Paris, France.
authors.forename: Patrick
authors.initials: P
authors.lastname: Bruneval
authors.affiliation: Department of Nephrology, Hôpital Européen Georges Pompidou, Paris, France.
authors.forename: Christian
authors.initials: C
authors.lastname: Jacquot
authors.affiliation: Department of Pathology, Hôpital Européen Georges Pompidou, Paris, France.
authors.forename: Dominique
authors.initials: D
authors.lastname: Nochy
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D018450:Disease Progression; D005260:Female; D005455:Fluorescent Antibody Technique; D005922:Glomerulonephritis, IGA / Q000145:classification* / Q000276:immunology / Q000401:mortality / Q000473:pathology / Q000628:therapy; D005923:Glomerulosclerosis, Focal Segmental / Q000145:classification* / Q000276:immunology / Q000401:mortality / Q000473:pathology / Q000628:therapy; D006801:Humans; D053208:Kaplan-Meier Estimate; D007678:Kidney Glomerulus / Q000276:immunology / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D010297:Paris; D050199:Podocytes / Q000276:immunology / Q000473:pathology; D011237:Predictive Value of Tests; D016016:Proportional Hazards Models; D006435:Renal Dialysis; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012720:Severity of Illness Index; D009626:Terminology as Topic; D013997:Time Factors; D016896:Treatment Outcome; D055815:Young Adult