[Clinico-histopathological analysis of renal changes in MPO-ANCA-associated vasculitis]

The pathological and clinical findings, therapies and prognoses of MPO-ANCA-associated vasculitis, were investigated in cases who showed rapidly progressive nephritic syndrome and received renal biopsy.

Vasculitis activity was evaluated by BVAS(Birmingham Vasculitis Activity Score). The renal biopsy findings were evaluated by scoring glomeruli, interstitial and vascular lesions. The renal prognoses were studied by dividing the cases into a dialysis group, which went onto maintenance dialysis in one year and another group without dialysis, which maintained renal functions.

The average age was 58.6 +/- 13.9 years, and the 60s age bracket was the largest. Vasculitis activity was 14.8 +/- 3.2 on the average by BVAS. CRP was 1.2 +/- 1.4 for the kidney-located type group, and 12.6 +/- 10.5 for the multiorgan-damaged group respectively, which shows the former to be significantly lower (p = 0.0079). Serum creatinine at renal biopsy was 3.57 +/- 2.31 mg/dL in the dialysis-independent group, and this was significantly lower than the serum creatinine level of 9.10 +/- 2.6 mg/dL of the dialysis group (p = 0.000259). As for the renal pathological findings, the percentage of global sclerosis among all the glomeruli was 24.7 +/- 19.9% in the dialysis-independent group vs. 68.5 +/- 19.7% in the dialysis group, which shows the latter to be significantly higher (p = 0.002).

CRP was significantly higher in the multi-organ-damaged group relative to the kidney-located type group. The percentage of global sclerosis determined by renal biopsy and the amount of serum creatinine at the renal biopsy were key factors in determining the renal prognosis. The absence of a significant correlation between the percentage of crescentic formation and the renal prognosis suggests the possibility of suppressing progress to global sclerosis.