Avascular necrosis of bone in systemic lupus erythematosus. The predictive role of precipitating autoantibodies.

The association between the type of precipitating autoantibodies and occurrence of avascular necrosis of bone (AVN) was examined. We prospectively analyzed clinical and laboratory findings of our 113 patients with SLE. Seven of 113 (6%) patients developed AVN. Anti-Ro (SS-A) and anti-RNP antibodies coexisted in 3 of 7 AVN patients. The same combination of these two antibodies were observed in 1 without AVN. Antibodies to topoisomerase I were detected in 2 other patients with AVN but not in any of the patients without AVN. The coexistence of the former two or the presence of the latter one is rare in SLE. However, these (combination of) antibodies can be useful as a local ischemic marker predicting the development of AVN.