Diagnostic performance of aPS/PT antibodies in neuropsychiatric lupus and cardiovascular complications of systemic lupus erythematosus

Abstract

Background: Systemic lupus erythematosus (SLE) is associated with a constellation of complications affecting multiple organs, including neuropsychiatric manifestations (NPSLE) and ischaemic events, leading to increased long-term morbidity. Antiphospholipid antibodies (aPL) are a major determinant of vascular inflammation and thromboembolic risk. The diagnostic role of anti-phosphatidylserine/prothrombin (aPS/PT) antibodies in this setting is incompletely defined.

Aim: To verify whether aPS/PT add to diagnostics and disease stratification in patients with SLE with or without other aPL.

Methods: 131 consecutive patients were studied, including 20 patients with SLE and secondary antiphospholipid syndrome (APS). aPS/PT IgG and IgM were assessed through ELISA and patients were stratified based on the presence of other aPL, on their clinical and laboratory features at time of blood sampling and on their clinical history. Synthetic indices of disease activity, chronic damage and cardiovascular risk were calculated at time of venipuncture.

Results: Fifty-one (38.9%) patients with SLE had aPS/PT and 15 (11.5%) patients had aPS/PT as the only aPL (aPS/PT-only). aPS/PT-only patients had a significantly higher prevalence of NPSLE than quadruple aPL-negative patients (p = .007). Patients with aPS/PT were more likely to have a history of ischaemia, thrombocytopenia and Libman–Sacks’ endocarditis. The presence of aPS/PT also associated with previous accrual of at least one damage item (p = .043), but had limited predictive values for damage progression in the short term.

Conclusion: aPS/PT antibodies provide non-redundant information that could contribute to risk assessment and stratification of patients with SLE.

Keywords:

• Anti-phosphatidylserine/prothrombin antibodies
• lupus
• antiphospholipid
• neuropsychiatric
• cardiovascular risk
• ischaemia
• thrombocytopenia
• thrombosis
• endocarditis
• pregnancy

Acknowledgments

The authors are grateful to the B.I.R.D. Foundation Europe, Costozza di Longare (VI), Italy for its support to our School of Allergy and Immunology and to INOVA Diagnostic, Inc. San Diego, CA USA for the generous gift of the aPS/PT IgG and IgM assays. The work in the authors’ laboratory has been supported by the Italian Ministry for University and Research (MIUR; Prin 2017) and by the Italian Ministry of Health (Ministero della Salute, RF2013). All authors have read the journal's policy on disclosure of potential conflicts of interest and declare that there is no conflict of interest.

Disclosure statement

The authors declare that there is no conflict of interest.

Additional information

Funding

The work in the authors’ laboratory has been supported by the Italian Ministry for University and Research (MIUR; Prin 2017) and by the Italian Ministry of Health (Ministero della Salute, RF2013).