Histopathologic Analysis of the Repeated Renal Biopsies in the Course of Lupus Nephropathy

Yoo, Chong Woo; Lee, Hyun Soon

Abstract

Lupus nephropathy shows a variable clinical course including remission, relapse and progression to renal failure. To examine the clinical or morphological parameters which might be related to the progression of lupus nephropathy, we have analyzed renal biopsies of 19 patients (M : F=5 : 14), who underwent repeated renal biopsies by morphology and morphometry. The average age of the patients was 22.8+/-9.0 years. The mean interval between two biopsies was 34.5+/-13.3 months. The first renal biopsies of these patients were diagnosed with WHO class IV (74%), class II (11%), class I (5%), class III (5%), and class V (5%). According to the clinical data the patients were divided into 3 groups, static, relapsing and progressive. At the time of the first biopsies, the amount of proteinuria in both the static and relapsing groups was significantly higher than that in the progressive group (P<0.05). The volume density of the renal cortical interstitium of the first biopsies in the progressive group was significantly greater than that in the static and relapsing groups (0.14+/-0.07 micrometer3/micrometer3 vs. 0.05+/-0.02 micrometer3/micrometer3, P<0.05; 0.14+/-0.07 micrometer3/micrometer3 vs. 0.05+/-0.04 micrometer3/micrometer3, P<0.05). The activity index of the second biopsies in the relapsing group was significantly higher than that in the static group (2.7+/-0.6 vs 1.2+/-1.0, P<0.05). In the progressive group, the percentage of glomeruli with global sclerosis and the volume density of the renal cortical interstitium in the second biopsies was elevated over the first biopsies (P<0.05). Half of the patients in the static and relapsing groups underwent a morphologic transformation on the second biopsy. However, of the 7 patients in the progressive group, only one showed a transformation from WHO class IV to class III, suggesting that the transformation is not related to the progression of lupus nephropathy. These results suggest that interstitial expansion and heavy proteinuria at the time of the first renal biopsy may bode for poor prognosis in lupus nephropathy. Furthermore, they suggest that an increased histologic activity index could be related to the relapse of the disease.