Immunogenicity and the vascular risk of oral contraceptives.

Data concerning circulating immune complexes were obtained for women who had had a pulmonary embolism, myocardial infarction, or cerebral thrombosis, and for 224 healthy controls. In women with pulmonary embolism who had used oral contraceptives concentrations of circulating immune complexes were significantly higher than in healthy controls (regardless of oral contraceptive use), or in those with pulmonary embolism who had never used these preparations. Concentrations of circulating immune complexes were not raised in myocardial infarction, but these women had major risk factors for ischaemic heart disease. The group of patients with cerebral thrombosis without risk factors tended to have high concentrations of circulating immune complexes. The data provide some confirmation that immunological mechanisms may play a role in thrombotic episodes associated with oral contraceptives, especially when they occur in the absence of risk factors for vascular disease.