[Anti-cardiolipin antibody and renal microthrombi in lupus nephritis].

To evaluate the relationship between anticardiolipin (ACL) antibody and microthrombi in renal tissue, we examined sera and renal biopsies from 47 patients of systemic lupus erythematosus (SLE) with lupus nephritis (LN). ACL antibody was measured by an enzyme-linked immunosorbent assay (ELISA). Their renal tissues were examined for histological types of lupus nephritis according to the WHO classification and appearance of renal microthrombi. Positive ACL had been shown in 28 of 47 patients (60%) with LN and in 15 of 18 patients (83%) with WHO IV (diffuse proliferative LN: DPLN). Incidences of renal microthrombi were significantly higher in patients with DPLN (61%) than in patients with all LN (34%) (p less than 0.01). The prevalence of renal thrombosis in patients with ACL (46%) was significantly higher than without ACL (16%) (p less than 0.05). Incidence of positive ACL was 81% in the cases with renal microthrombi and 48% in the cases without them. These findings suggest that there is strong association between ACL and the renal microthrombi in active LN.