Anticardiolipin antibodies are associated with pulmonary hypertension in patients with mixed connective tissue disease or systemic lupus erythematosus.

Anticardiolipin antibodies (aCL) were studied in relation to pulmonary hypertension (PH) in 22 patients with mixed connective tissue disease (MCTD) or systemic lupus erythematosus (SLE). The mean pulmonary arterial pressure (mPAP) values were similar in the 12 MCTD and 10 SLE patients: 26 +/- 11 and 25 +/- 11 mm Hg, respectively. However, the frequency of PH was higher in SLE (60%) than in MCTD patients (33%). The titers of aCL were significantly higher in SLE (38 +/- 27 IU/ml) than in MCTD (17 +/- 7 IU/ml; p < 0.02). Two SLE patients with high titers of aCL had multiple cerebral infarction and transverse myelitis, and deep vein thrombosis, respectively. A significant correlation between the titers of aCL and mPAP was observed in patients with MCTD (p < 0.05), but not in patients with SLE.