The clinical significance of non-criteria antiphospholipid antibodies in atypical antiphospholipid syndrome

OBJECTIVES: To analyse the correlation between non-criteria antiphospholipid antibodies (non-criteria aPLs) and clinical symptoms (recurrent miscarriage) in patients with seronegative antiphospholipid syndrome (SNAPS). METHODS: Ninety-four SNAPS patients who were treated in the First Affiliated Hospital of Soochow University from May 2022 to May 2024 were included. Chemiluminescence immunoassay was used to detect anti-β2 glycoprotein I antibody, anti-cardiolipin antibody, and lupus anticoagulant. Enzyme-Linked Immunosorbent Assay (ELISA) was used to detect the levels of anti-annexin A5 (ANXA5), anti-phosphatidylethanolamine antibody (aPE), anti-prothrombin Immunoglobulin G (IgG) antibody (aPT IgG), anti-prothrombin Immunoglobulin M (IgM) antibody (aPT IgM), anti-phosphatidylserine/prothrombin IgG antibody, and anti-phosphatidylserine/prothrombin IgM antibody. The correlation between non-criteria aPLs and clinical events was analysed. RESULTS: Compared with the non-criteria antibody-negative group, the positive group had a higher rate of positive antinuclear antibodies (P < .05). The proportion of recurrent miscarriage in the positive non-criteria antibody group was significantly higher than in the negative group (P = .002). Compared with the negative group, patients with positive ANXA5 antibody and aPT IgM were more likely to have recurrent miscarriage (P < .05). Compared with the aPE-negative group, those with aPE-positive were more likely to experience early miscarriage (P = .039). Both aPT IgM subtype (P = .004) and ANXA5 (P = .013) antibodies were the risk factors for recurrent miscarriage. Patients with positive ANXA5, anti-prothrombin IgG, and aPT/PS IgM antibodies showed a significant decrease in antibody titers after treatment (P < .05). CONCLUSIONS: Detection of non-criteria aPLs contributes to improving the diagnosis of SNAPS, assessing its development trends, and intervening promptly to prevent recurrent miscarriage.