OBJECTIVETo understand the clinical and pathological characteristics of IgA nephropathy (IgAN) with crescentic formation in children.

METHODSClinicopathological data of 29 children with IgAN accompanied by crescents were analyzed. These patients were divided into two groups according to the percentage of glomeruli affected by crescents more or less than 50%, and their data were compared.

RESULTS(1) CLINICAL FEATURES: all the patients had hematuria and proteinuria, and macrohematuria (86%) and proteinuria were also common, protein excreted in urine was more than 1 g per day in 76% of the patients. The patients with edema, hypertension, and renal insufficiency were less than fifty percent. Nine patients in Group A (glomeruli affected by crescents > or = 50%) were crescentic IgAN. Significantly more cases in Group A had persistent macrohematuria, hypertension and renal failure than in Group B (glomeruli affected by crescents < 50%) (P < 0.05), with especially severe proteinuria (P < 0.01). It was easy to find nephritic syndrome in Group A, and asymptomatic hematuria combined with proteinuria in Group B. (2) Renal pathology: the glomeruli were affected by crescents from 5% to 85%. There were 52% to 85% in Group A, and 5% to 40% in Group B. Most crescents were cellular. All the cases had a diffuse mesangial proliferation and tubular-interstitial injury to different degree. Three cases had crescentic IgAN. Glomerulosclerosis was significantly more often seen in Group A (P < 0.05) and tuft adhesion was more frequently seen in Group B (P < 0.05). (3) Immunofluorescence: All the patients presented deposition of IgA, IgM and C3. There were 45% specimens combined with the deposition of IgG. Five cases showed 'full house' (17%), four of them were in Group A. None had IgA deposition alone.

CONCLUSIONThe main clinical feature of IgAN with crescentic formation were hematuria combined with proteinuria, especially persistent gross hematuria and severe proteinuria. All of them showed diffuse mesangial proliferation and tubular-interstitial injury in morphology of kidney. Most of them had tuft adhesion. The main type of immunofluorescence were IgA + IgM and IgA + IgM + IgG deposition. Some showed 'full house' phenomenon. The clinical manifestation and renal lesions of IgAN with diffuse crescentic formation were worse than IgAN with glomeruli affected by crescents < 50%.