Analysis of risk factor for patients and renal survival in anti-myeloperoxidase antibody (MPO-ANCA) associated glomerulonephritis

Abstract

We investigated the clinical and histological features and the outcome of 15 patients with antimyeloperoxidase antibody(MPO-ANCA) associated glomerulonephritis. The patients were divided into two groups on the basis of renal functional outcome: Group 1 consisted of 7 patients where an initial deterioration in renal function was improved at the final observation. Group 2 included 8 patients who had a progressive deterioration in renal function leading to end stage renal disease or chronic dialysis, or who died. We compared the clinical and histological features at renal biopsy and the outcome following steroid therapy between the two groups. Group 1 patients had significantly lower levels of serum creatinine and UN, and higher values for creatinine clearance (Ccr) than Group 2 patients(1.9 +/- 0.6 vs. 6.7 +/- 4.7 mg/dl, 29 +/- 7 vs. 73 +/- 39 mg/dl, 30 +/- 9 vs. 10 +/- 5 ml/min, p < 0.05, respectively). Histologically, Group 1 patients had a significantly lower percentage of crescent formation than Group 2 patients(41 +/- 6 vs. 74 +/- 4%, p < 0.05), whereas there was no significant difference in tubulo interstitial damage between the 2 groups. Moreover, in 4 patients of Group 1 where a second renal biopsy was performed two months after steroid therapy, marked attenuation in acute tubulo-interstitial changes was observed in association with a rapid improvement of renal function. These results suggest that diffuse tubulo-interstitial inflammatory changes despite a relatively low frequency of cellular crescent formation may be a prognostically important histological feature showing a good response to steroid therapy.