Renal Amyloidosis Secondary to ANCA-Associated Vasculitis: A Case Report / 中国医学科学杂志(英文版)

Renal amyloidosis secondary to anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis is extremely rare. Here, we reported a 77-year-old woman with ANCA-associated vasculitis. Renal biopsy with Masson trichrome staining showed pauci-immune crescentic glomerulonephritis, and electron microscopy showed amyloid deposition in the mesangial area. Immunofluorescence revealed kappa light chain and lambda light chain negative. Bone marrow biopsy revealed no clonal plasma cell. Finally, she was diagnosed as ANCA-associated vasculitis with secondary renal amyloid A amyloidosis.

ANCA-positive vasculitis: Clinical implications of ANCA types and titers / Vasculite ANCA positiva: implicações clínicas dos tipos e dos títulos de ANCA

SUMMARY Introduction: Anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis is an autoimmune disease that can affect multiple organs, the kidney being one of the most affected. Apart from the diagnostics value of ANCA, they have also been advocated as biomarkers of the disease activity. Recently, the genetic changes found in polyangiitis associated with serine-protease proteinase 3 (PR3)-ANCA or myeloperoxidase (MPO)-ANCA raised the possibility of immune-pathogenic and therapeutic differences. Objective: To identify differences in the number of relapses, inflammatory markers, outcomes and renal histology related to the types of ANCA. To analyze the implications of ANCA titers in prognosis. Method: A retrospective observational study in a Portuguese tertiary hospital. Results: There were no differences in the progression of renal function, histological pattern and initial treatment with regard to ANCA subtypes. As for the evaluated parameters, there were no significant differences according to the types of ANCA, except for mean CRP values within the normal range, which was 6.3±1.3 mg/L for MPO-ANCA and 12.4±10.14 mg/L for PR3-ANCA (p=0.04). We found that 66.7% of the MPO-ANCA-positive showed no relapses versus 40% in the case of PR3-ANCA-positive. There was no correlation between the ANCA titers at presentation, during remission, and in the last evaluation, and the number of relapses. Conclusion: PR3-ANCA patients have a mean CRP value within the normal range significantly higher than that of MPO-ANCA patients (p=0.04), which seems to reveal greater inflammatory activity in the first.

RESUMO Introdução: a vasculite associada aos anticorpos anticitoplasma de neutrófilos (ANCA) é uma doença autoimune que pode acometer vários órgãos, sendo o rim um dos mais afetados. Além dos ANCA serem marcadores de diagnóstico, foram também defendidos como marcadores de atividade. Recentemente as alterações genéticas encontradas entre as poliangeítes serina-protease 3 da proteinase (PR3)-ANCA ou mieloperoxidase (MPO)-ANCA levantam a possibilidade de diferenças imunopatogênicas e terapêuticas. Objetivos: identificar diferenças quanto a número de recidivas, marcadores inflamatórios, desfechos e histologia renal relativamente aos tipos de ANCA. Analisar implicações dos títulos de ANCA no prognóstico. Método: estudo retrospectivo observacional em hospital terciário português. Resultados: não se verificaram diferenças quanto à evolução da função renal, ao padrão histológico e ao tratamento inicial relativamente aos subtipos de ANCA. Nos parâmetros analíticos avaliados, não se verificaram diferenças significativas relativas aos tipos de ANCA, à exceção do valor médio de PCR no intervalo que foi de 6,3±1,3 mg/L nos MPO-ANCA e 12,4±10,14 mg/L nos PR3-ANCA (p=0,04). Verificamos que 66,7% dos MPO-ANCA positivos não apresentaram recidivas versus 40% dos PR3-ANCA positivos. Não se verificou nenhuma correlação entre os títulos de ANCA à apresentação, durante a remissão e na última avaliação com o número de recidivas. Conclusão: os indivíduos PR3-ANCA apresentaram um valor médio de PCR nos intervalos superior aos indivíduos MPO-ANCA (p=0,04), o que parece evidenciar uma maior atividade inflamatória nos primeiros.

Renal histology in pauci-immune rapidly progressive glomerulonephritis: 8-year retrospective study.

Context: The need to perform reporting of renal biopsies of antineutrophil cytoplasmic antibodies (ANCA)-associated vasculitides in a more uniform manner required relook at our eight-year data. Aims: To document detailed renal histopathology of pauci-immune rapidly progressive glomerulonephritis (RPGN) and also to seek any significant differences in renal histology of C-ANCA-positive, P-ANCA-positive, and ANCA-negative patients. Materials and Methods: A detailed analysis of the histopathologic features of renal biopsies of 48 patients in whom a diagnosis of pauci-immune glomerulonephritis was concluded on renal biopsy and who presented clinically as rapidly progressive renal failure was done. Statistical Analysis Used: One-way ANOVA and Pearson Chi square tests. Results: Compared with ANCA +ve patients, the ANCA -ve patients were much younger (46.85 ± 16.12 years vs 34.28±15.94 years). No significant differences were found between renal lesions of C-ANCA, P-ANCA, and ANCA-negative patients, except for diffuse tubular atrophy which was more severe and more frequently present with P-ANCA positivity (P value=0.013). Conclusions: Pauci-immune RPGN (irrespective of ANCA status) is a relatively rare disorder in patients who are undergoing the renal biopsy at our institute, constituting 2% of all renal biopsies submitted. It is mandatory to have ANCA serology status during reporting of a kidney biopsy showing pauci-immune crescentic or necrotizing glomerulonephritis. Also, if a uniform reporting strategy is followed throughout the country, the studies from this vast country will be comparable.

Crescentic glomerulonephritis: A clinical and histomorphological analysis of 46 cases.

Background: Crescentic glomerulonephritis (CrGN), defined as crescents involving more than 50% of the glomeruli, includes pauci-immune, immune complex-mediated and anti-glomerular basement membrane disease. Objectives: The present study was aimed at evaluating the various clinical, biochemical and histological parameters in CrGN with respect to these categories and clinical outcome. Materials and Methods: Renal biopsies diagnosed as CrGN between Jan 2008 and Feb 2010 were included. Clinical and laboratory parameters were retrieved along with the therapeutic approach and clinical outcome, wherever available. Renal biopsy slides were evaluated for various glomerular, tubulo-interstitial and arteriolar features. Appropriate statistical tests were applied for significance. Results: A total of 46 cases of CrGN were included; majority (71.7%) of cases were pauci-immune (PI) while 28.3% were immune complex-mediated (IC). Among clinical features, gender ratio was significantly different between PI and IC groups (P = 0.006). The various histological parameters, including proportion of cellular crescents, tuft necrosis and Bowman's capsule rupture, were similar in both the groups. Four unusual associations, including idiopathic membranoproliferative glomerulonephritis (MPGN), multibacillary leprosy, acute lymphoblastic leukemia and C1q nephropathy were detected. Adequate follow-up information was available in 21 (46%) of the patients. Of these, 11 (52.4%) were dialysis-dependent at the last follow-up. Adult patients required renal replacement therapy more frequently than pediatric cases (P = 0.05). Presence of arteriolar fibrinoid necrosis also showed association with poor clinical outcome (P = 0.05). Conclusions: Crescentic glomerulonephritis remains one of the main causes of acute renal failure with histological diagnosis. Immunohistologic examination is essential for accurate classification into one of the three categories. This condition should be considered in rare causal associations like leprosy or MPGN with renal failure, to allow for timely performed renal biopsy and appropriate aggressive therapy.