Multiple Arterial Thrombosis in Seronegative Antiphospholipid Syndrome: Need for New Diagnostic Criteria?

BACKGROUND: Antiphospholipid syndrome (APS) is defined as thromboembolic complications and/or pregnancy morbidity in the presence of persistent increased titres of antiphospholipid antibodies. Nevertheless, some patients with clinical signs suggestive of APS are negative for diagnostic antibodies and may be classified as having seronegative-APS (SN-APS). Among the ‘non-diagnostic’ antibodies, a few studies have suggested that the IgG anti-vimentin/cardiolipin antibodies (AVA/CL) may be associated with risk of thrombosis. AIMS: The aim of this case report is to encourage the assessment of non-conventional antibodies in APS. Patient and methods: We report the case of a 69-year-old male patient with rapid onset of apparently unexplained multiple exclusively arterial thrombotic events in both coronary and peripheral vascular beds. RESULTS: The patient did not meet the diagnostic criteria for APS but was positive for AVA/CL, which result persisted on further testing at 3 and 6 months. DISCUSSION: Ongoing research has revealed the existence of non-criteria antibodies which may be relevant for the diagnosis of SN-APS and should be included in the classification criteria for the disease. LEARNING POINTS: In patients with unexplained multiple thrombosis without the conventional antibodies of antiphospholipid syndrome, the assessment of non-conventional antibodies should be considered. IgG anti-vimentin/cardiolipin antibodies may be associated with risk of thrombosis. Arterial thrombosis could be the only manifestation of antiphospholipid syndrome.