ANA-positive versus ANA-negative Antiphospholipid Antibody-positive Patients: Results from the Antiphospholipid Syndrome Alliance for Clinical Trials and International Networking (APS ACTION) Clinical Database and Repository (“Registry”)

Objectives: This study focused on the prevalence and impact of ANA in aPL-positive patients without concomitant systemic autoimmune rheumatic diseases (SARDs). Methods: Data from aPL-positive patients with or without Revised Sapporo APS classification criteria were retrieved from the Antiphospholipid Syndrome Alliance for Clinical Trials and International Networking (APS ACTION) Registry. Patients with concomitant SARDs were excluded. Results: A total of 430 aPL-positive patients were included in the analysis, 56% ANA-positive (ANA+) and 44% ANA-negative (ANA-). ANA positivity was significantly associated with history of haematologic manifestations (persistent autoimmune haemolytic anaemia, thrombocytopenia, leukopenia and/or lymphopenia) (16% of ANA+ vs 7% of ANA-, P = 0.006). Triple aPL-positivity was more frequent in the ANA+ subgroup (P = 0.02), along with low baseline C3 and C4 levels (P = 0.05 and P = 0.009, respectively), and higher frequency for ENA. Among aPL-positive patients with no APS classification, ANA+ patients showed a higher rate of arthritis (P = 0.006). Among female patients who have experienced at least one pregnancy, 113 were ANA+ and 96 were ANA-; ANA- patients had a higher number of pregnancies (P = 0.018), and number of live births (P = 0.014). A wider proportion of ANA+ patients were treated with HCQ (P < 0.001). Conclusion: When we analysed aPL-positive patients with no other SARDs, ANA status was not associated with thrombosis or pregnancy morbidity. Interestingly, ANA+ patients showed higher rates of systemic autoimmune features, including haematologic manifestations, multiple aPL positivity, lower complement levels, ENA positivity, and joint involvement, and were more often treated with HCQ. Finally, aPL-positive subjects who were ANA- had a higher rate of pregnancies and live births.