Antiphosphatidylethanolamine antibodies as the only antiphospholipid antibodies. I. Association with thrombosis and vascular cutaneous diseases.

OBJECTIVE: To detect antiphosphatidylethanolamine antibodies (aPE) as the only antiphospholipid antibodies (aPL) in 122 patients we investigated for aPL and to correlate the presence of aPL with clinical manifestations.
METHODS: Patients with autoimmune diseases (n = 41), thromboembolic episodes (TEE) (n = 34), livedo reticularis (LR) without (n = 17) or with (n = 14) thrombosis or recurrent fetal losses (RFL), systemic vasculitides (n = 10), and miscellaneous disorders (n = 6) were investigated for antibodies directed against 4 anionic phospholipids (PL) (cardiolipin, phosphatidylserine, inositol, phosphatidic acid) and lupus anticoagulant (LAC) and then for aPE by modified ELISA.
RESULTS: 15 patients had aPE and no antibodies to anionic PL including LAC. 7 had IgM, 4 had IgG plus IgM, and 4 had IgG. These aPE were significantly more often associated with TEE alone, with TEE and LR, or with LR alone (p = 0.004) than with autoimmune diseases.
CONCLUSION: The detection of aPE as the sole aPL in one patient with mesenteric infarcts and RFL led to the diagnosis of primary antiphospholipid syndrome. Followup of 3 patients showed that aPE cannot be considered as transient autoantibodies. Therefore, patients whose clinical symptoms suggest antiphospholipid syndrome but whose sera are negative for antibodies to cardiolipin or another anionic PL should be screened for aPE, particularly patients with thrombosis, RFL, and/or LR.