ANCA-associated glomerulonephritis: Relationship of main ANCA subtypes to renal outcome, age and sex of the patients

Sex disparities in clinicopathological features and outcomes of patients with myeloperoxidase-ANCA-associated vasculitis: a retrospective study of 366 cases in a single Chinese center

There are a few studies that reported sex disparities in clinical features, pathological features and outcomes among ANCA-associated vasculitis (AAV) patients, but studies focusing on sex-specific differences of myeloperoxidase (MPO)-AAV patients are scarce. Therefore, the purpose of this study was to analyze sex differences in clinicopathological features and outcomes of MPO-AAV. Patients diagnosed with MPO-AAV in Xiangya Hospital from January 2010 to June 2021 were included in the study and separated into female and male groups. The differences in clinical manifestations, laboratory parameters, pathological features and prognosis between the two groups were retrospectively analyzed. Three hundred and sixty-six patients were included and divided into female group (n = 176) and male group (n = 190). The age of the male group was 62.41 ± 10.49 years, significantly higher than that of the female group (58.69 ± 16.39, p = 0.011). Compared with the female group, the male group had a shorter duration of disease, higher levels of hemoglobin, eosinophil count, proteinuria, serum C4, and lower levels of serum globulin, serum IgG and serum IgM (p < 0.05). No significant differences in kidney pathological features were observed between the two groups. During a median follow-up of 37.6 months, there was no significant difference in renal survival and patient survival between the two groups, but male patients had a worse composite outcome of renal and patient survival compared with the female patients (p = 0.044). This study found that male patients with MPO-AAV had a higher age of onset, shorter duration of disease, higher levels of hemoglobin, eosinophil count, proteinuria, serum C4, and lower levels of serum globulin, serum IgG and serum IgM. Male patients fared worse than female patients in terms of the composite outcome of renal and patient survival.

Histopathological classification of pauci-immune glomerulonephritis and its impact on outcome

Rapidly progressive renal failure is a common but severe feature of antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis. A histopathological classification for ANCA-associated pauci-immune glomerulonephritis was developed for prognostication of these patients. The present study aims to classify patients of pauci-immune glomerulonephritis according to this classification and its impact on outcome. Eighty-six subjects with pauci-immune glomerulonephritis between July 2006 and October 2012 were included in the study. Their renal biopsies were reviewed and classified into focal, crescentic, sclerotic and mixed class as per the new classification. The outcomes were analyzed after 6 months of treatment. Of the 86 subjects, 34 (39.53 %) were granulomatosis with polyangiitis, 36 (41.86 %) microscopic polyangiitis, 1 eosinophilic granulomatosis with polyangiitis, while the rest (17.44 %) were unclassifiable. Thirteen (15.5 %), 43 (51.2 %), 12 (14.3 %) and 16 (19 %) patients were classified as focal, crescentic, sclerotic and mixed class, respectively. The mean serum creatinine at baseline was 280.23, 659.46, 573.72 and 542.78 µmol/L in focal, crescentic, sclerotic and mixed class, respectively. The probability of improvement in renal functions at 6 months decreased from focal to crescentic to mixed to sclerotic class, while the probability of death was highest in the sclerotic class followed by the mixed class. This difference in outcome was maintained irrespective of the clinical diagnosis or the Birmingham Vasculitis Activity Score. Our study has shown that the histopathological classification can be used to predict the severity of renal dysfunction as well as the treatment outcomes in pauci-immune glomerulonephritis.

Introduction to, and classification of, the systemic vasculitides

This overview serves as an introduction to the systemic vasculitides, which are a group of heterogeneous disorders sharing a common pathophysiological mechanism leading to blood vessel inflammation and tissue necrosis. Our lack of understanding of the aetiology for most forms of vasculitis has resulted in the development of a classification system, which is primarily based on vessel size. Such a system assists in the grouping together of similar conditions for the purposes of multi-centre studies. Difficulties arise in classification of the vasculitides due to considerable overlap of clinico-pathological features; for example, microscopic polyangiitis (MPA), Wegener's granulomatosis (WG) and Churg-Strauss syndrome (CSS) may all cause the identical renal lesion of necrotizing glomerulonephritis. The rationale for treatment often depends on the type of vasculitis and on the extent of organ involvement. Treatment may be similar for different types of disease. The lack of validated diagnostic criteria has, however, resulted in the application of classification criteria in their place, and has highlighted the limited usefulness of classification criteria in clinical practice. Classification systems should assist in the determination of therapy and prediction of outcomes, but have many limitations, which are discussed further in this review.