28 3Focal segmental glomerulosclerosis in IgA nephropathy with regard to Oxford classification: Does it matter? 
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Portuguese Journal of Nephrology & Hypertension

 ISSN 0872-0169

COSTA, Rui M; VAZQUEZ-MARTUL, Eduardo; REBOREDO-MOSQUERA, Juan    RIVERA, Constantino. Transplant glomerulopathy and post-transplant de novo thrombotic microangiopathy: common features and pathologic mechanisms. []. , 28, 3, pp.219-230. ISSN 0872-0169.

^len^aAim: Comparison between transplant glomerulopathy (TG) and de novo thrombotic microangiopathy (TMA) in renal allograft biopsies in a 10 -year retrospective analysis. Results: Out of a total of 627 biopsies, TG (6.2%) was diagnosed at a later stage (6.9 ± 5.9 vs. 3.5 ± 6.5 years, p = 0.01) and presented higher proteinuria (4.0 ± 3.6 vs. 2.3 ± 1.6 gr/24h, p = 0.02), advanced glomerulosclerosis, interstitial fibrosis/tubular atrophy and interstitial plasma cells (30.8% vs. 0%, p = 0.02). De novo TMA (2.2%) was associated to worse graft disfunction (sCr 4.9 ± 1.8 vs. 2.7 ± 0.2mg/dl, p < 0.01), older donors (53 ± 10 vs. 41 ± 17 years, p = 0.04), PRA levels ≥ 25% (16.7% vs. 3.1%, p = 0.07) and previous rejection events (21.4% vs. 5.3%, p = 0.08). Diffuse glomerular lesions were observed in all TMA cases, with capillary congestion (100 vs. 35.1%, p < 0.01), microthrombi (50% vs. 5.4, p = 0.01), schistocytes (42.8% vs. 7.7%, p = 0.01) and mesangiolysis (85.7% vs. 29.7%, p < 0.01). Positive C4d in de novo TMA cases was similar to TG (71.4% vs. 53.8%, p = ns) but presented arteriolar C4d deposition (35.7 % vs. 8.7%, p = 0.042). Donor -specific antibodies detection was equally found (TG: 41.6%; TMA: 57.1%, p = ns), mainly anti-HLA Class II. In ultrastructural analysis only TG cases presented glomerular basement membrane (GBM) multilayering. Graft loss was similar, but de novo MAT cases had worst first year survival (73.3% vs. 97%, p = 0.013). Conclusion: Both pathologies belong within the spectrum of microcirculatory injury: TG results from subclinical lesion, presenting chronic cyclic accommodation, de novo TMA represents severe form of lytic endothelial lesion^lpt^aObjectivo: Comparação retrospectiva entre a glomerulopatia de transplante (GT) e microangiopatia trombótica (MAT) de novo num período de 10 anos de biópsias de enxertos renais. Resultados: No total de 627 biopsias, GT (6,2%) foi diagnosticada mais tardiamente (6.9 ± 5.9 vs. 3.5 ± 6.5 anos, p = 0.01), com maior grau de proteinúria (4.0 ± 3.6 vs. 2.3 ± 1.6 gr/24h, p = 0.02), glomeruloesclerose, fibrose intersticial e atrofia tubular mais severas e presença de plasmócitos intersticiais (30.8% vs. 0%, p = 0.02). Os casos de MAT de novo >(2,2%) apresentavam disfunção do enxerto mais severa (sCr 4.9 ± 1.8 vs. 2.7 ± 0.2mg/dl, p < 0.01) e associação com dadores mais velhos (53 ± 10 vs. 41 ± 17 anos, p = 0.04), níveis de PRA ≥ 25% (16.7% vs. 3.1%, p = 0.07) e episódios prévios de rejeição aguda (21.4% vs. 5.3%, p = 0.08). Lesões glomerulares difusas foram detectadas em todos os casos de MAT, especialmente com congestão capilar (100% vs>. 35.1%, p < 0.01) e predomínio de presença de microtrombos (50% vs>. 5.4 %, p = 0.01), esquizócitos (42.8% vs. 7.7%, p = 0.01) e mesangiólise (85.7% vs. 29.7%, p < 0.01). Positividade para C4D em MAT de novo e TG foi semelhante (71.4% vs. 53.8%, p = ns) mas a deposição arteriolar de C4d foi mais frequente em MAT de novo (35.7 % vs. 8.7%, p = 0.042). A detecção de anticorpos anti -dador foi similar entre os dois grupos (GT: 41.6%; MAT: 57.1%, p = ns) e constituído maioritariamente por anticorpos anti-HLA Classe II. Apenas a GT apresentava multilaminação da membrana basal glomerular na microscopia electrónica. A perda do enxerto foi semelhante entre as duas patologias mas MAT de novo apresentou pior sobrevida renal ao primeiro ano (73.3% vs>. 97%, p = 0.013). Conclusão: GT e MAT de novo são expressões histológicas que se incluem num espectro de lesão da microcirculação: a GT resulta de lesão subclínica, apresentando acomodação crónica cíclica e a MAT de novo expressa uma forma severa de lise endotelial

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