Stages of IgA nephropathy：
1. Ⅰlevel of IgA nephropathy stage: The glomerular in this stage most are normal, sometimes occur mild mesangial broadening accompany with hyperplasia, kidney tubules and renal interstitium not change, this is the lightest stage of IgA nephropathy.
2. Ⅱ level of IgA nephropathy stage: In this IgA nephropathy stage, the glomerular will show focal mesangial proliferation and hardening (<50%), there is a rare small crescent, kidney tubule and renal interstitial without damage.
3.Ⅲ level of IgA nephropathy stage: In this IgA nephropathy stage, the glomerular present diffuse mesangial proliferation and broadening (sometimes occur focal segmental), sometimes occur small new month body ; kidney tubule and renal interstitial changes will present focal renal interstitial edema, sometimes see cellular infiltration, rarely seen renal atrophy.
4.Ⅳ level of IgA nephropathy stage: Glomerular lesions present serious diffuse mesangial proliferation and hardening, part or complete glomerular sclerosis can see crescent (<45%).Renal tubular atrophy, cellular infiltration, incidental renal interstitial foam cells.
5.Ⅴ level of IgA nephropathy stage: The character of glomerular lesions is similar to Ⅳ level, more serious, glomerular crescent formation >45% .In this stage of IgA nephropathy ,IgA nephropathy lesion is very serious, so it is difficult to cure, the treatment of IgA nephropathy is the same as Ⅳ level treatment, just need to strictly therapeutic schedule, or have a long-term treatment.