Antiphospholipid antibodies. A prognostic factor in sarcoidosis?

Serum antibodies against five types of phospholipids, antiphospholipid antibodies (aPL), were determined by an enzyme-linked immunosorbent assay in 55 patients with sarcoidosis. Either IgG or IgM aPL were detected in 21 patients (38 percent). This positive rate was significantly higher than that (7 percent) of healthy control subjects (p < 0.001). In terms of immunoglobulin classes, 5 cases had IgG aPL only, 11 cases had IgM aPL only, and 5 cases had both classes of aPL. No correlation was observed between the occurrence of aPL and disease activity of sarcoidosis. A significant correlation was noted between the occurrence of aPL and many extrathoracic organ lesions or the persistence of abnormal chest x-ray film findings for periods of 2 and 5 years. Taken together, the presence of aPL in sarcoidosis is a useful index to judge the prolongation of the disease.