Renal biopsy in systemic lupus erythematosus: significance of glomerular thrombosis. Analysis of 108 cases.

We investigated the frequency and distribution of glomerular thrombosis (GT) in 108 renal biopsies of lupus patients and correlated this finding with the presence of anticardiolipin antibodies (ACLA). GT was present mainly in the diffuse proliferative form. The activity index was higher in those patients with GT (12.9 +/- 4.7 vs 5.4 +/- 4.1, P < 0.01). The more severe histologic features, necrosis and extracapillary proliferation were also related with GT. In 18 cases with repeated biopsy the best predictors for the subsequent development of glomerular sclerosis were fibrinoid necrosis (P < 0.01), glomerular infiltration (P < 0.01) and an activity index of 10 or more (P < 0.05). GT also showed to be an important prognostic factor for sclerosis, although no statistically significant. ACLA were investigated in 36 patients at the time of renal biopsy. There were nine positive cases and in three of them this finding was related to GT. We can conclude that GT is a relevant feature showing active lupus nephritis and that it is not related to the presence of ACLA.