Anticardiolipin IgA as a Potential Risk Factor for Pregnancy Morbidity in Patients with Antiphospholipid Syndrome

Antiphospholipid syndrome (APS) is an autoimmune disorder that is characterized by venous or arterial thrombosis and/or obstetric morbidity in the constant presence of persistent antiphospholipid antibodies (aPLs). In patients with APS, the relationship between production of immunoglobulin (Ig)A antiphospholipid antibodies and adverse events in pregnancy is still unclear. As a result of massive trials, the clinical efficiency of IgA-aPLs is used to evaluate pregnancy outcomes in patients with APS.

We enrolled 381 female patients with APS and 93 healthy pregnant women. Silica clotting time ratio, dilute Russell viper venom time (dRVVT) ratio, and 6 aPLs, including IgA/IgG/IgM isotypes aβ2GPI and IgA/IgG/IgM isotypes anticardiolipin (aCL), were detected using commercial kits.

We found no significant differences in laboratory parameters between patients with APS and the control group. The total prevalence of aCL IgA was 2.9%; the prevalence of aβ2GPI IgA was 3.4%. Only 1.3% of the individuals who tested aCL-positive (5/381) had isolated aCL IgA. Similarly, isolated aβ2GPI IgA was present in only 0.8% (3/381) of the aβ2GPI-positive subjects. Meanwhile, aCL IgA showed the maximum area under the curve (AUC) of 0.666 (95% CI, 0.60-0.73; P < .001), followed by dRVVT ratio (AUC = 0.649; 0.58-0.72; P < .001).

Positive aCL IgA and aβ2GPI IgA ratios were extremely low for each isolated isotype of aPLs. For patients with APS who experienced fetal loss, aCL IgA may be utilized as a risk factor for pregnancy loss among patients with APS. Establishing a standardized diagnosis of IgA aPLs is also important for these patients.