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 micromol/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 micromol/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.