Anti-phosphatidyl-serine/prothrombin (aPS/PT) antibodies are superior predictors of LAC presence and APS diagnoses: A single center study

• Published in: Clinica chimica acta 2024-02, Vol.554, p.117761-117761, Article 117761
• Main Authors: Saadalla, Abdulrahman, Nandakumar, Vijayalakshmi
• Format: Article
• Language: English
• ISSN: 0009-8981; 1873-3492
• DOI: 10.1016/j.cca.2024.117761

•aPS/PT titers are higher in the presence of LAC and criteria antibodies.•aPS/PT IgM showed the highest combined sensitivity and specificity for APS diagnosis.•aPS/PT antibodies are more specific indicators of LAC presence than aB2GPI or aCL antibodies. Several non-criteria (NC) anti-phospholipid antibodies (APLA) have been proposed as candidates for antiphospholipid antibody syndrome (APS) diagnosis. The objectives of this study were 1) to determine the association of five different NC-APLA with positivity for Lupus anti-coagulant (LAC) and the criteria antibodies anti-cardiolipin (aCL) and anti-beta glycoprotein (aB2GPI), and 2) to assess the ability of NC-APLA to predict LAC presence and clinical APS diagnoses. Results from 486 patients tested for LAC and APLA were retrieved. Patients were grouped according to LAC and serology positivity into three groups: Single-positives (SP) for LAC, aCL or aB2GPI; Double-positives for aCL and aB2GPI; Triple-positives (TP) for LAC, aCL and aB2GPI. NC-ALPA titers were compared between LAC-positive and negative and APS and non-APS patients. Forty-two of 486 patients were LAC-positive and 28 were diagnosed with APS. All criteria and NC-APLA titers were significantly higher in TP than SP patients. ROC analyses based on LAC status showed highest area under the curve (AUC, 95% CI) for aPS/PT IgG (0.75, 0.65–0.85) and aPS/PT IgM (0.73, 0.63–0.82). Based on APS diagnosis, aPS/PT IgM achieved highest AUC (0.87; 0.79–0.95). Anti-phosphatidyl-serine/prothrombin (aPS/PT) antibodies are superior predictors of LAC presence and APS diagnoses.