[Prevalence of antiphospholipid antibodies in Horton's disease and in polymyalgia rheumatica].

Purpose: Antiphospholipid antibodies (APL) are frequently observed in the course of giant cell arteritis and polymyalgia rheumatica. However, their role and relationships with potential ischemic events are still debated.

Methods: To determine the prevalence of APL in relation with ischemic events, 62 patients with giant cell arteritis and/or polymyalgia rheumatica were retrospectively studied.

Results: Before corticosteroid treatment 41% of the 51 patients with giant cell arteritis and 64% of the 11 patients with isolated polymyalgic rheumatica had high IgG ACL levels, with a frequency significantly higher than that (15.6%) of the control group which was composed of healthy elderly. IgM ACL were found in only two patients with giant cell arteritis. There was no correlation between the occurrence of an ischemic event (22 ischemic events in the 51 patients with giant cell arteritis) and the presence of ACL, even though the latter were more frequently observed in the giant cell arteritis group (52% versus 41% in non ischemic patients). The prevalence of ACL increased, reaching 59% if lupus anticoagulant was associated, but the difference was not significant. ACL disappeared soon after corticosteroid therapy had been initiated.

Conclusion: Though ACL are frequently seen in giant cell arteritis and/or polymyalgia rheumatica, they are not related to ischemic events and disappear rapidly after corticosteroid treatment.