Antiphospholipid antibodies and retinal thrombosis in patients without risk factors: A prospective case-control study

PURPOSE: To determine the prevalence of antiphospholipid antibodies and oth er immunologic abnormalities in patients with occlusive retinal vascular ev ents, exempt from conventional risk factors of retinal thrombosis. METHODS: Forty patients with retinal vascular occlusion (26 with retinal ve in occlusions, eight with arterial occlusions, two with combined venous and arterial occlusions, and four with venous occlusions plus vasculitis), fre e of main accepted risk factors for retinal thrombosis, were prospectively screened for antiphospholipid antibodies (anticardiolipin-antibodies and lu pus anticoagulant) and other immunologic abnormalities. Fourteen patients w ere younger than 50 years. Prevalence and mean values of antiphospholipid a ntibodies (aPL) were compared with those in a homogeneous control group of 40 patients. RESULTS: The prevalence of antiphospholipid antibodies in the study group w as 22.5% (nine of 40), Comparison with control group prevalence (5% [two of 40]) showed a statistically significant difference (P = .04). Six patients in the study group disclosed positivity for IgG-anticardiolipin antibodies , one patient for IgM anticardiolipin antibodies, and two patients for both isotypes IgG and IgM anticardiolipin antibodies. The antibody assay for: l upus anticoagulant was negative for all patients. Three patients were diagn osed as having primary antiphospholipid antibody syndrome and are undergoin g systemic anticoagulant therapy. Relevant immunologic abnormalities were a lso found (27.5% with antinuclear antibodies, 35% with elevation of circula ting immune complexes, 35% with complement deficiency, 30% with positive rh eumatoid factor, and 17.5% with positive C-reactive protein). Thirteen pati ents (32.5%) had more than four-parameters altered, No significant associat ion was found between prevalence or mean values of anticardiolipin antibody and patients younger than 50 years. CONCLUSIONS: The high prevalence of anticardiolipin antibodies in patients with vaso occlusive retinopathy exempt from conventional risk factors, and the relevant diagnostic and therapeutic implications, lead us to recommend a systematic search for specific antiphospholipid antibodies in such patien ts. (C) 1999 by Elsevier Science Inc. All rights reserved.