title: Extracapillary proliferation is an independent predictive factor in Immunoglobulin A nephropathy.
abstract: BACKGROUND
  Oxford classification of Immunoglobulin A Nephropathy (IgAN) identifies four pathological features as predictors of renal outcome (MEST-score): mesangial proliferation (M); endocapillary proliferation (E); segmental glomerulosclerosis (S); tubular atrophy/interstitial fibrosis (T). In particular extracapillary proliferation (Ex) was not considered as an independent histological variable predicting renal outcome. Recently the VALIGA study provided a validation of the Oxford classification in a large European cohort of IgAN patients and re-stated that Ex is not associated with a worse renal prognosis. We propose a retrospective study to evaluate the predictive value of the MEST-score in a multi-centre, single region group of patients from central Italy and in addition, to investigate Ex as a marker predicting renal outcome.
  
  
  METHODS
  One hundred and seven patients were enrolled in this study. Clinical data of each patient were available at diagnosis and follow-up. The median age at diagnosis was 36.7 years; 72% of the patients were males. Histological parameters were those included in the MEST-score of the Oxford classification; in addition, Ex was also assessed.
  
  
  RESULTS
  Multiple linear regression models for survey were used. Statistical analysis showed a correlation between the progression of renal decline, in terms of estimated glomerular filtration rate (slope eGFR), and M, S, T. Differently from Oxford and VALIGA studies, no correlation was found with E, while Ex correlated with a decline of eGFR.
  
  
  CONCLUSIONS
  Our results suggest that Ex represents an additional independent variable associated with a faster decline of renal function in IgAN.
authors.affiliation: Nephrology and Dialysis Department, Belcolle Hospital, Viterbo, Italy.
authors.forename: Ilaria
authors.initials: I
authors.lastname: Serriello
authors.affiliation: Nephrology and Dialysis Department, Belcolle Hospital, Viterbo, Italy.
authors.forename: Rosaria
authors.initials: R
authors.lastname: Polci
authors.affiliation: Nephrology and Dialysis Department, Belcolle Hospital, Viterbo, Italy.
authors.forename: Sandro
authors.initials: S
authors.lastname: Feriozzi
authors.affiliation: Department of Clinical Medicine, Sapienza University of Rome, Rome, Italy.
authors.forename: Antonietta
authors.initials: A
authors.lastname: Gigante
authors.affiliation: Nephrology, Dialysis and Transplantation Department, San Camillo Hospital, Rome, Italy.
authors.forename: Salvatore
authors.initials: S
authors.lastname: Di Giulio
authors.affiliation: Nephrology, Dialysis and Transplantation Department, San Camillo Hospital, Rome, Italy.
authors.forename: Margherita
authors.initials: M
authors.lastname: Rosa
authors.affiliation: Nephrology and Dialysis Department, S. Pertini Hospital, Rome, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Galliani
authors.affiliation: Nephrology and Dialysis Department G.B. Grassi Hospital, Ostia, Rome, Italy.
authors.forename: Massimo
authors.initials: M
authors.lastname: Morosetti
authors.affiliation: Nephrology and Dialysis A Unit, Sapienza University of Rome, Rome, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Pugliese
authors.affiliation: Health Department, University Campus Biomedico, Rome, Italy.
authors.forename: Tommasangelo
authors.initials: T
authors.lastname: Petitti
authors.affiliation: Department of Medicine and Surgery, Pathology Unit, Campus Bio-Medico University of Rome, Rome, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Onetti Muda
authors.affiliation: Department of Radiology, Oncology, Radiology and Pathology, Sapienza University of Rome, Rome, Italy.
authors.forename: Konstantinos
authors.initials: K
authors.lastname: Giannakakis
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001706:Biopsy; D049109:Cell Proliferation; D018450:Disease Progression; D005260:Female; D005919:Glomerular Filtration Rate; D005922:Glomerulonephritis, IGA / Q000473:pathology* / Q000503:physiopathology; D006801:Humans; D007558:Italy; D007678:Kidney Glomerulus / Q000473:pathology* / Q000503:physiopathology; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D055815:Young Adult
keywords: Immunoglobulin A nephropathy; end-stage kidney disease; glomerulonephritis; immunopathology; renal biopsy