Evaluation of the newly proposed simplified histological classification in Japanese cohorts of myeloperoxidase-anti-neutrophil cytoplasmic antibody-associated glomerulonephritis in comparison with other Asian and European cohorts

Abstract

The prognostic value of renal biopsy in anti-neutrophil cytoplasmic antibody (ANCA)-associated glomerulonephritis is widely recognized; however, there is no consensus regarding its pathological classification. Berden et al. proposed a new classification of glomerulonephritis in ANCA-associated vasculitis (AAV) categorized into focal, crescentic, mixed, and sclerotic classes and showed its prognostic value in 100 international multicenter cohorts for 1- and 5-year renal outcomes. In order to evaluate whether this new classification has predictive value and reproducibility in Japanese AAV cases, 87 cohorts with only microscopic polyangiitis in 3 limited centers in Japan were analyzed. In addition, those from Japan, Europe (Berden’s cohorts) and China were compared in a recent report.

The New Histopathologic Classification of ANCA-Associated GN and Its Association with Renal Outcomes in Childhood

“…One consistent finding, however, in contrast to the original study, has been that the mixed category confers better renal survival than does crescentic disease (5,19,20). We have a small number of children with mixed pathologic features in contrast to all the adult studies but a similar number with crescentic pathologic features (50%); this is more in keeping with the European and Chinese cohorts (47%-55%) and dissimilar to findings in Japan, where only 8% of the population had crescentic disease.…”

“…We have a small number of children with mixed pathologic features in contrast to all the adult studies but a similar number with crescentic pathologic features (50%); this is more in keeping with the European and Chinese cohorts (47%-55%) and dissimilar to findings in Japan, where only 8% of the population had crescentic disease. This could reflect varying disease processes as all the patients in the Japanese study had antibodies to myeloperoxidase (5,19). Although outcomes for patients with ANCA GN have improved substantially over the last decade, attributable to earlier diagnosis and better therapeutic strategies, renal involvement in AAV is common, occurring in about 88% of childhood cases and 80% of adult cases (2,20,22).…”

“…Several validation studies of the new pathologic criteria have been published and have demonstrated reliability in predicting outcomes for patients with focal or sclerotic disease in ANCA GN (18)(19)(20)(21). One consistent finding, however, in contrast to the original study, has been that the mixed category confers better renal survival than does crescentic disease (5,19,20).…”

Prognostic Value of Histologic Classification of ANCA-Associated Glomerulonephritis

“…Taking previous findings into account, they proposed four classes: sclerotic (.50% globally sclerotic glomeruli), focal (,50% affected glomeruli), crescentic (.50% active cellular crescents), and mixed (,50% normal/crescentic/sclerotic glomeruli). To our knowledge, this classification model has now been applied to 12 independent patient cohorts (8,(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20). Generally, in univariate analyses, investigators have correlated a favorable prognosis with the focal group and a poor prognosis with the sclerotic group.…”

Anti-Neutrophil Cytoplasmic Antibody-Associated Vasculitis in Mexican Population: Clinical Phenotype, Autoantibody Profile and Renal Characteristics

“…The distribution of the four renal histological categories is similar in Europe, Canada, India and China, with crescentic class being the dominant, whereas in Japan the focal class predominates, and in USA the mixed [7,23,[27][28][29][30][31][32][33]. The presence of impaired renal function, and the low percentage of normal glomeruli (<25%) in our population are factors known to be associated with poor renal outcome [25,34,35].…”