PO:14:205 | Primary antiphospholipid antibody syndrome: association between new classification criteria manifestations and a higher-risk disease phenotype

Sara Ferrigno¹, Vittorio Forte², Marco Panetta¹, Sergio Lisena¹, Giorgia Ranucci², Luigi De Marco¹, Elisabetta Greco¹, Alberto Bergamini¹, Maria Sole Chimenti¹, Paola Conigliaro¹. | ¹Rheumatology, allergology and clinical immunology, Department of Systems Medicine, University of Rome Tor Vergata, Rome, Italy; ²Hematology, Department of Biomedicine and Prevention, University of Rome Tor Vergata, Rome, Italy.

Background. The 2023 ACR/EULAR classification criteria for primary antiphospholipid antibody syndrome (PAPS) included new disease manifestations contributing to the definition of the syndrome. However, their prognostic role and association with clinical and serological features have yet to be well elucidated. Aim of the study was to evaluate prevalence of new criteria manifestations both in a PAPS and in an antiphospholipid antibodies (aPL) carrier cohort. Additionally, we investigated their associations with PAPS clinical and serological characteristics.

Methods. We enrolled a cohort of PAPS patients meeting the Sapporo classification criteria. Demographic, clinical and serological data were retrospectively collected, including type of first thrombotic/obstetric event, recurrence, presence of traditional cardiovascular (CV) risk factors (hypertension, dyslipidemia, diabetes, chronic kidney failure), serologic profile, ongoing treatments. The presence of the new manifestations included in the 2023 ACR/EULAR classification criteria was also evaluated. Same parameters were collected from a cohort of aPL carriers. Patients with autoimmune diseases were excluded. Categorical variables were compared using the 2 test, continuous variables were compared using t-test or Mann-Whitney U test. Variables with statistical significance were further tested in a binary logistic regression model.

Results. 65 PAPS patients, 41 with thrombotic, 16 with obstetric syndrome, 8 with both, and 66 aPL carrier were enrolled (Table 1). PAPS patients showed significantly higher prevalence of new classification criteria manifestations compared to aPL carriers, as expected. Moreover, PAPS patients had higher prevalence of CV risk factors compared to carriers, but similar aPL serologic profiles. Among the PAPS cohort, 19 patients had at least one New classification Criteria manifestation in their clinical history (NC-PAPS). Particularly, 2 patients had cardiac valve thickening, 9 livedoid vasculopathy and 10 thrombocytopenia. Our results showed that NC-PAPS have higher prevalence of thrombotic PAPS, while the other group showed higher prevalence of obstetric syndromes. Looking at thrombotic PAPS, NC-PAPS patients showed significantly higher prevalence of arterial events and higher prevalence of recurrences. They also showed higher prevalence of Lupus Anticoagulant, anti-cardiolipin (ACLA) IgG and triple positivity (Table 2). Traditional CV risk factors were comparable between the two groups. Finally, NC-PAPS patients were more likely to be under hydroxychloroquine treatment compared to PAPS. In a multivariate analysis including arterial events as dependent variable, NC-PAPS and triple positivity as covariates, NC-PAPS patients resulted to have 5-times higher probability to have history of arterial events, independently of triple aPL positivity (OR 5.2, 95%CI 1.5-17.6).

Conclusions. New classification criteria manifestations seem to be more prevalent in PAPS patients with history of arterial events, thrombotic recurrence and in patients with LA, ACLA-IgG and triple positivity, suggesting their correlation with a higher-risk disease phenotype.