Frequency of vascular and pregnancy morbidity in patients with low vs. moderate-to-high titers of antiphospholipid antibodies

Abstract

Antiphospholipid syndrome (APLS) is an autoimmune hypercoagulable syndrome characterized by thrombotic and obstetric manifestations. We sought to determine the rate of APLS feature in patients tested positive for antiphospholipid antibodies (APLA) regardless of the serum level of anticardiolipin (ACL) and/or anti-β2-glycoprotein I (β2GPI) antibodies. An inception cohort of individuals who were tested positive for ACL and/or β2GPI IgG/IgM antibody, and/or lupus anticoagulant (LAC) on two occasions of at least 12 weeks apart. A total of 243 patients were included; their mean age was 40.1 ± 15.9 years. Thrombotic vascular events occurred in 118 patients (48.5%) of the entire cohort, of which 62 patients (25.5%) suffered from an arterial event and 56 patients (23%) from thrombotic venous events. Obstetrical morbidity occurred in 106 female patients (43.6%). In our cohort, we found no difference in the frequency of thrombotic or obstetric manifestations of APLS between patients with ACL IgG/IgM of low serum antibody level (<40 U) and medium-to-high level (≥40 U) and/or anti-β2GPI IgG, IgM higher than the 99th percentile vs. lower (>20 U). We suggest that in 'real life' the diagnosis of APLS should not be excluded because of low titer of APLA.

The European Registry on Obstetric Antiphospholipid Syndrome (EUROAPS): A survey of 1000 consecutive cases

“…There is evidence that APS is the most frequently treatable acquired cause during pregnancy [14], although it is known that the classic form and the obstetric one have different rates of thrombosis [15], response to treatment [16] or follow-up [17]. Those incomplete forms (by meeting neither the clinical nor the laboratory criteria) represent a special challenge for the clinician [18], as there is increasing evidence that patients with low aPL titers can experience poor pregnancy outcomes similarly to high-titer patients [19]. In the same way, women with incomplete clinical forms benefit from treatment, having better prognosis than women without treatment [20].…”

The association between antiphospholipid antibodies and late fetal loss: A systematic review and meta‐analysis

“…Some authors suggest that the APLA titer is of clinical interest, especially in APLA‐related pregnancy complications where low‐to‐medium antibody titer has been suggested to be of clinical relevance . At the same time, there is increasing evidence that patients with low APLA titers can experience poor pregnancy outcomes similarly to high‐titer patient . These observations suggest that low titer APLA can play a significant role in obstetric APS and that the actual classification criteria do not include all the obstetric APS cases .…”

“…41 At the same time, there is increasing evidence that patients with low APLA titers can experience poor pregnancy outcomes similarly to high-titer patient. [41][42][43] These observations suggest that low titer APLA can play a significant role in obstetric APS and that the actual classification criteria do not include all the design as its main selection criterion. We focused on case-control, prospective and retrospective cohort, and cross-sectional studies because of the varying but complementary information about the types of APLA and the risk of late fetal loss.…”

Obstetric Anti-phospholipid Syndrome: State of the Art

“…Risk factors associated with adverse pregnancy outcomes include: high number of previous pregnancy losses [53] As for the antibody titer, conflicting results exist. Even though high positive antibody titers are associated with adverse pregnancy outcome [60, 61], there is increasing evidence that patients with low-titer aPL can experience poor pregnancy outcomes similarly to high-titer aPL patients [69][70][71][72][73]. These observations suggest that in contrast to thrombotic events, low-titer aPL can play a significant role in ob-APS and that the current classification criteria may not allow to include all the ob-APS cases.…”