Idiopathic IgA Nephropathy with Diffuse Crescent Formation

Abstract

Objective: To investigate the clinicopathological features and outcome of idiopathic IgA nephropathy with diffuse crescent formation in Chinese patients. Methods: Twenty-five patients with diffuse crescentic IgA nephropathy (DCIgAN), 15 males and 10 females with median age of 28.5, and median disease duration of 5.1 months, were studied. Their clinical, laboratory and pathological features and outcome were investigated. Twenty-one were administered pulse immunosuppressive therapy, and 15 were followed up for more than 6 months. Results: 1.14% had total IgA nephropathy, and 16.4% total diffuse crescentic glomerulonephritis. Clinically, most of patients (88%) showed rapidly progressive glomerulonephritis associated with a high level of serum creatinine (418 ± 264 µmol/l). Gross hematuria was noted in 72%, hypertension in 64%, and nephrotic syndrome in 48%. Pathologically, except for diffuse crescent formation (a median 65% and range 50–95%), we observed segmental necrosis of glomerular capillaries in 60%, glomerular infiltrating cells in 48%, endothelial cells proliferation in 32%, and rupture of Bowmans’ capsule in 24%. Severe tubular interstitial damage was also found, tubular atrophy in 64%, interstitial fibrosis in 60%, diffuse interstitial infiltrating cells in 74%, and interstitial vasculitis in 40%. Immunopathologically, four phenotypes were observed; however, IgA associated with IgM deposition was higher than that in patients with general IgA nephropathy (IgAN). In addition, the infiltrating CD4+, CD8+, CD68+ and PCNA+ cells in renal tissue were significantly high compared with that in controls. In a follow-up study, 66.7% of patients had life-sustaining renal function, 4 of them had normal range of serum creatinine (<124 µmol/l), and only 5 were dialysis-dependent. Conclusions: The patients with crescentic IgA nephropathy mostly show rapidly progressive nephritis associated with more severe pathological changes including glomerular, tubular interstitial and vascular lesions than in patients with general IgAN. The infiltrates in glomeruli may contribute to the crescentic formation, and the intensive immune suppressing treatment is useful to improve renal damage in patients with DCIgAN.

Prediction of Outcomes in Crescentic IgA Nephropathy in a Multicenter Cohort Study

“…5 In another study with 25 Chinese patients who had IgAN with diffuse crescent formation, most of the patients exhibited rapid deterioration of kidney function. 8 With immunosuppressive therapy, approximately 67% of these patients maintained sufficient kidney function to avoid renal replacement therapy. However, the high incidence of loss to follow-up (10 of 25 patients) greatly limited the study results.…”

“…However, the high incidence of loss to follow-up (10 of 25 patients) greatly limited the study results. 8 Because of the small sample size and limited study power of the above studies, neither of them could assess the risk factors for crescentic IgAN. In the recent Oxford classification of IgAN, patients with rapidly progressive kidney failure were excluded, and thus, crescentic IgAN was not evaluated.…”

“…2,6 Crescentic IgAN affects only a minority of IgAN patients and has not been widely investigated, except in a few small studies. 5,7,8 The recent Kidney Disease: Improving Global Outcomes (KDIGO) guidelines for GN recommended that crescentic IgAN be treated using an immunosuppressive therapy regimen analogous to the regimen used for ANCA vasculitis. 6 Until now, most studies on crescentic IgAN have been case series or small studies with less than 30 patients.…”

“…6 Until now, most studies on crescentic IgAN have been case series or small studies with less than 30 patients. 7,8 Little is known about the long-term outcomes and risk factors that influence kidney recovery in patients with crescentic IgAN, 9 especially those patients who have undergone initial aggressive immunosuppressive therapy. We, therefore, examined the long-term outcomes of a large cohort of 113 patients who were diagnosed with crescentic IgAN using the criterion of crescents in more than 50% of glomeruli on biopsy specimens.…”

Idiopathic IgA Nephropathy

“…The incidence of extracapillary proliferation is also poorly documented. Tang et al (29) retrospectively examined 2186 biopsies from patients with IgA disease and documented that up to 2% of patients had cellular crescents in Ͼ50% of glomeruli. …”