Correlation among WHO classes, histomorphologic patterns of glomerulonephritis and glomerular immune deposits in SLE

In addition to the conventional World Health Organization (WHO) classificat ion of lupus glomerulonephritis (GN), various concomitant approaches have b een introduced in the evaluation of renal biopsies of patients with systemi c lupus erythematosus (SLE) in order to increase the impact of biopsies on the decision concerning the most appropriate therapy as well as for establi shing the prognosis. Three hundred and seventy kidney tissue samples from 267 SLE patients were analysed using standardised light, electron and immunofluorescence microsco pic techniques. In 155 patients, a comparative clinical follow-up study and statistical analysis were performed. The study highlighted the heterogenei ty of WHO classes IV and III, which include 5 and 6 different conventional histomorphologic types of GN, respectively. Mixed membranous and proliferat ive GN associated with "full-house" mesangial-transmembranous immune deposi ts, demonstrated in more than one third of our SLE cases, appears to be dia gnostically most characteristic. Immune deposits distributed in the glomeru li in five different patterns, obviously play a major role in the pathogene sis of various WHO classes and histomorphologic types of lupus GN. Addition al mechanisms related to the occurrence of antiphospholipid antibodies and antineutrophil cytoplasmic antibodies are suggested to contribute to the hi stomorphologic heterogeneity of WHO class III and IV lupus GN, particularly to the development of thrombotic, necrotising and crescentic glomerular le sions. In the present study, a statistically significant association was demonstra ted between increasing mean values of the activity index and glomerular dep osit distribution patterns labeled by subendothelial deposits. Furthermore, a significant correlation was established between an increasing risk of de veloping renal failure and increasing mean values of the chronicity index. Differences in the increasing risk of developing renal failure between grou ps with different histomorphologic types of GN and different immune deposit distribution patterns were not statistically significant. The surprisingly high renal survival rate of more than 80% noted in lupus patients with pre dominantly necrotising crescentic GN during the mean follow-up period of 40 months appears to be related to the more aggressive treatment of those pat ients. Our study confirmed a significant role of the WHO classification of lupus GN in the decision concerning the most appropriate treatment and prog nostication. An increasing risk of irreversible renal failure in patients w ith WHO class IV lesions in contrast to those of WHO class III and in contr ast to those of the category incorporating all other WHO classes was shown to be statistically significant.