Prevalence of Antiphospholipid Antibodies Negativisation in Patients with Antiphospholipid Syndrome: A Long-Term Follow-Up Multicentre Study

Abstract

Objective This article aims to analyse the rate of antiphospholipid antibodies (aPL) negativisation in patients with antiphospholipid syndrome (APS), and to evaluate potential new clinical manifestations after negativisation and/or aPL fluctuations in a long-term follow-up. Methods Inclusion criteria are (1) any patients with an APS diagnosis according to the current Sydney criteria and (2) patients in whom aPL negativisation occurred. aPL negativisation was defined as repeated aPL measurements on at least two consecutive occasions at least 12 weeks apart, with a follow-up of at least 1 year since aPL first turned negative. Results Out of 259 APS patients, a total of 23 patients (8.9%) met the inclusion criteria for persistent aPL negativisation. Patients were followed-up for 14.4 ± 8.1 years, experienced aPL negativisation after a mean of 5.3 ± 3.5 years and were followed-up after experiencing the aPL negativisation for a mean of 7.6 ± 5.8 years. Seventeen patients (73.9%) presented with thrombotic APS, 2 with pregnancy morbidity (8.7%) and 4 (17.4%) with both. Most of the patients (18; 78.3%) had a single aPL positivity, 5 (21.7%) double, while no triple aPL positivity was observed. At the time of data collection, after aPL negativisation, anticoagulation was stopped in 8 patients with previous thrombotic venous event (8/21, 38%) according to the treating physicians' judgements. None of the patients experienced any recurrent thrombotic event during the follow-up period after their aPL negativisation. Conclusion In our patient cohort consisting of 259 patients with definitive APS, we observed over a mean observation period of > 5 years, that aPL negativisation occurred in approximately 9% of patients. Negativisation occurred most often in patients who were previously found to be positive for only one aPL.

Systematic review of observational studies reporting antiphospholipid antibodies in patients with solid tumors

“…aPL antibodies are well known as an acquired immune-mediated risk factor for thromboembolic events 1,2,73 ; however, the exact mechanisms mediating the development of aPL antibodies in cancer are poorly understood. Conceivably.…”

Clinical Delphi on aPL Negativization: Report from the APS Study Group of the Italian Society for Rheumatology (SIR-APS)

“…4 5 28 29 30 The rates of patients who experience aPL negativization and the aPL profile of seroconverted patents are also a matter of debate. Recent studies report rates of aPL negativization in APS patients from 8.9% 5 to as high as 29.1%. 30 With regard to the aPL profile of seroconverted patients, 29 31 reported data range from 23 to 78% in the case of single aPL positivity, from 22 to 38% in the case of double positivity, while triple aPL seroconversion is reported in Zen et al's cohort to be as high as 38%, even though most of the reported positivity cases were at low titer (20–40 U/mL).…”

“…When it comes to titer, negativization is noted for aPL tested in solid-phase assays that range from low to medium–high titer values. 4 5 30…”

Thrombosis and Haemostasis 2019 Editor's Choice Papers

“…36 Aside from ready known risk factors, the authors identified endometriosis and recurrent pregnancy loss as novel independent risk factors for VTE. For its part, the long-term observational follow-up study from Radin et al 37 shed light on the ill-investigated anti-phospholipid antibodies seroconversion in anti-phospholipid syndrome patients. The present study gave new cues to a difficult clinical scenario, and should help physicians to take a decision on continuation of OAC in this specific case.…”