Nefropatia por IgA: análise histológica e correlação clínico-morfológica em pacientes do Estado de Minas Gerais / IgA nephropathy: histological analysis and clinicomorfological correlation in patients from Minas Gerais State

INTRODUÇÃO: A Nefropatia por IgA (NIgA) é a glomerulopatia primária mais comum. OBJETIVO: Classificar a NIgA segundo a nova proposta de Classificação de Oxford. MÉTODOS: Foram analisadas biópsias do Serviço de Nefropatologia da UFTM, no período de 1996 a 2010, com diagnóstico de NIgA. Foram avaliados gênero, idade, presença de hematúria, padrões/intensidade das lesões, deposições de IgA, IgG, IgM, Kappa, Lambda, C3, C1q e fibrinogênio. Histologicamente, as biópsias foram caracterizadas conforme a Classificação de Oxford, e realizou-se a correlação clínico-morfológica. RESULTADOS: Das 164 biópsias avaliadas, houve predomínio do gênero masculino (53,7%) e adulto (93,3%). Caracterizando os pacientes conforme a classificação de Oxford, obtivemos predominância M0 (85,3%), S1 (53,1%), E0 (65,2%) e T0 (70,1%). À correção clínico-morfológica, observamos maior proteinúria M1 em relação a M0 (p < 0,008), menor taxa de filtração glomerular estimada (p < 0,001) e maior frequência de hipertensão (p < 0,001) comparando-se T0,T1 e T2. À imunofluorescência, predominância de IgA (100% dos casos), com codeposição de C3 (99,37% dos casos), Kappa (96,25%), Lambda (91,25%) e IgM (76,92%). Foi observada correlação entre a intensidade de deposição de IgA com C3, Kappa e Lambda. CONCLUSÃO: No presente estudo, a NIgA foi predominante em homens, mais comuns foram os padrões M0, S1, E0 e T0, com maior proteinúria e aumento da hipercelularidade mesangial, além de maior prevalência de hipertensão/pior função renal conforme a gravidade das repercussões túbulo-intersticiais.

INTRODUCTION: IgA nephropathy (IgAN) is the most common primary glomerulopathy. OBJECTIVE: Classify IgAN according to the new Oxford's classification. METHODS: We analyzed the renal biopsies from the Nephropathology Service of UFTM, among 1996 to 2010, with a diagnosis of IgAN. We assessed gender, age, presence of hematuria, patterns/intensity of the lesions, deposition of IgA, IgG, IgM, Kappa, Lambda, C3, C1q and fibrinogen. Based on the histological alterations, the biopsies were characterized according to the Oxford Classification, and the clinicomorfological correlation was made. Significative results for p < 0,05. RESULTS: A total of 164 cases biopsies, predominantly male (53.7%) and adults (93.3%). We characterized the patients according Oxford Classification, there was a predominance of the pattern M0 (85,3%), S1 (53,1%), E0 (65,2%) e T0 (70,1%). About the clinicomorfological correlation, we observed more severe proteinuria comparing M1 to M0 (p < 0,008), low estimated GFR (p < 0,001) and more frequent hypertension (p < 0,001) comparing T0, T1 e T2. On immunofluorescence, there is a predominance of IgA (100% of cases), with codeposition of C3 (99.37% of cases), Kappa (96.25%), Lambda (91.25%) and IgM (76.92%). Correlation was found between IgA intensity and C3, Kappa and Lambda. CONCLUSION: In this study, IgA nephropathy was predominant in males, the more frequent patterns were the M0, S1, E0 and T0, with more severe proteinuria and the enhance of mesangial hypercellularity, besides larger prevalence of hypertension/worse kidney function according the tubulo-interstitial injuries.

Validation of the Oxford Classification of IgA Nephropathy: A Single-Center Study in Korean Adults

BACKGROUND/AIMS: The recently published Oxford classification of IgA nephropathy (IgAN) proposed a split system for histological grading, based on prognostic pathological features. This new classification system must be validated in a variety of cohorts. We investigated whether these pathological features were applicable to an adult Korean population. METHODS: In total, 69 adult Korean patients with IgAN were analyzed using the Oxford classification system at Soonchunhyang University Hospital, Seoul, Korea. All cases were categorized according to Lee's classification. Renal biopsies from all patients were scored by a pathologist who was blinded to the clinical data for pathological variables. Inclusion criteria were age greater than 18 years and at least 36 months of follow-up. We excluded cases with secondary IgAN, diabetic nephropathy combined other glomerulopathies, less than 36 months of follow-up, and those that progressed rapidly. RESULTS: The median age of the patients was 34 years (range, 27 to 45). Mean arterial blood pressure was 97 +/- 10 mmHg at the time of biopsy. The median follow-up period was 85 months (range, 60 to 114). Kaplan-Meier analysis showed significant prognostic predictions for M, E, and T lesions. A Cox proportional hazard regression analysis also revealed prognostic predictions for E and T lesions. CONCLUSIONS: Using the Oxford classification in IgAN, E, and T lesions predicted renal outcome in Korean adults after taking clinical variables into account.

IgA nephropathy: an update on pathogenesis and classification

IgA nephropathy is a primary glomerulopathy characterized by deposition of IgA containing immune deposits in the kidney. Its diagnosis is based on histopathologic and immunoflourescence studies on renal biopsy. The disorder is poorly understood. This review is focused on updates regarding its pathogenesis and discussion on a new proposed histopathological classification of IgA nephropathy

Glomerulonefrítis Mesangial por depósitos de IgA (Enfermedad de Berger)

La nefropatía mesangial IgA o nefropatia IgA, fue descrita primero por Berger en 1968 y puede ser identificada por la localización mesangial glomerular del IgA, con una localización meangial menos intensa de IgG o IgM, o ambos y C3. La etiologia y la patogénesis de la nefropatía IgA son desconocidas. Su frecuente asociación con las infecciones no estreptocócicas del tracto respiratorio superior sugieren que una nefropatía IgA puede representar una nefritis por complejo inmune en la cual, la infección de la mucosa provee un antígeno exógeno, posiblemente viral, que se combina con IgA para producir un complejo que se localiza en el mesangio. Existe muy poca información para evaluar la utilidad de la terapia en la nefropatía IgA.