To observe the clinical and pathological features of primary IgA nephropathy with glomerular crescents formation, and to analyze its response to treatment with corticosteroids and cyclophosphamide.

From August 1997 to April 2015 in the First Hospital Affiliated to Baotou Medical College, a total of 80 patients of primary IgA nephropathy with crescents formation confirmed by renal biopsy were divided into group A (area ratio of crescents to involved glomeruli ≥50%) (n=28) and group B (area ratio of crescents to involved glomeruli <50%) (n=52). Glomerular mesangial proliferation and renal tubular interstitial lesions were quantified with scores by the Katafuchi criteria. And the clinical and pathological features were also compared. Treatment plan: both group A and group B were divided into corticosteroids subgroup, and corticosteroids plus cyclophosphamide subgroup. Follow-up was made in group A and group B with 24 cases each. And statistical analysis was made with the SPSS software.

Microscopic hematuria and proteinuria occurred in 32 patients (40%); 76 patients (95%) had proteinuria no less than 2 g/24 h; 32 patients (40%) had macrohematuria; edema, hypertension, and abnormal kidney function were found in more than 50% of the patients. In group A, proteinuria was significantly higher than in group B (t=1.890, P<0.05), while serum albumin and glomerular filtration rate were significantly lower than in group B (t=2.681, t=3.014; P<0.05). The area percentage of the crescents over the affected glomeruli was 5.92%-88.9% totally, 52.6%-88.9% in group A, and 5.92%- 48.9% in group B. Compared with group B, group A had more serious renal tubular damage (P<0.05). After treatment with corticosteroids plus cyclophosphamide, quantitative proteinuria was significantly reduced in both group A and group B (χ²=4.010, χ²=4.902, P<0.05). After the corticosteroids therapy, the reduction of serum creatinine was more significant in group A than in group B (χ²=5.882, P<0.05). After followed-up for 2-4 years, 8 cases had elevated serum creatinine that met the dialysis indications, and 1 case died in group A; 2 cases had increased serum creatinine (one case with slight baseline elevation, and the other with new elevation of serum creatinine).

In the patients with IgA nephropathy, with increase of the proportion of crescents area over the affected glomeruli, the renal tubulointerstitial pathological damage and clinical manifestation gradually aggravated with poor prognosis. In the primary IgA nephropathy with big crescents formation, the corticosteroids therapy could decrease proteinuria and might be able to improve the renal function.