Abstract Number: PB1932
Meeting: ISTH 2020 Congress
Theme: Thrombotic Microangiopathies » Antiphospholipid Syndrome
Background: Current laboratory classification criteria for definite Antiphospholipid syndrome (APS) require the demonstration of lupus anticoagulant (LA), and/or anticardiolipin (aCL) and/or anti-b2glycoprotein I (a-β2GpI) IgG or IgM antibodies detected by immune-sorbent method. Triple positivity (LA, aCL and a-β2GpI antibodies) is associated with high thrombotic risk.
Traditionally aCL and a-β2GpI antibodies were detected by enzyme linked immunosorbent assay (ELISA), but nowadays more advanced automated platforms with reduced interlaboratory variation are available: fluorescence enzyme immunoassay (EliA), luminex and chemiluminescence assays (CliA). As reported in the literature triple positivity identification is assay dependent.
Aims: Aim of our study was to investigate whether CliA Acustar (Instrumentation Laboratories, Bedford, Massachusetts, United States) have better performances than EliA ImmumnoCAP (Thermo Fisher Scientific Phadia, Upssala Sweden) assay in triple positivity aPL detection.
Methods: We collected and studied, 30 consecutive LA positive patient samples, in accordance with the revised three-step diagnostic strategy of the ISTH, on whom an aPL determination was requested coming from Clinical Immunology or Haematology Department. aCL and a-β2GpI IgG/M antibodies were determined by our in house platform EliA ImmunoCAP and by CliA Acustar.
Results: Clinical characteristics and results are reported in Table 1 and 2. By using CliA ACL Acustar assay the percentage of triple-positive cases increased significantly in all LA positive patients investigated [10/30 (33%) ImmunoCAP versus 17/30 (57%) Acustar, p< 0.05]. Table 1. Discr... Table 2. Discre...
Conclusions: In conclusion as reported in the literature our data shows that detection of triple-positivity was better with CliA than EliA assay. As triple-positivity APS patients have an increased risk of thrombotic recurrence, standardization in triple-positivity detection is urgently warranted.
| Clincal Characteristics of LA positive patients | Number | aCL IgG ImmunoCAP | aCL IgM ImmunoCAP | aB2GpI IgG ImmunoCAP | aB2GpI IgM ImmunoCAP | aCL IgG Acustar | aCL IgM Acustar | aB2GpI IgG Acustar | aB2GpI IgM Acustar |
| APS thrombosis | 13 | 5 (38%) | 6 (46%) | 5 (38%) | 6 (61%) | 10 (76%) | 9 (81%) | 11 (85%) | 8 (61%) |
| APSpregnancy morbidity | 1 | 1 (100%) | 1 (100%) | 1 (100%) | 0 | 1 (100%) | 1 (100%) | 1 (100%) | 1 (100%) |
| Non APS thrombosis | 5 | 0 | 0 | 0 | 1 (20%) | 0 | 0 | 0 | 0 |
| Autoimmune Disease | 11 | 1 (9%) | 2 (18%) | 0 | 5 (45%) | 2 (18%) | 2 (18%) | 2 (18%) | 2 (18%) |
| Total | 30 | 7 (23%) | 9 (30%) | 6 (20%) | 12 (40%) | 13 (43%) | 13 (43%) | 14 (46% | 11 (36%= |
[ Table 1. Discrepancies in solid phase immunoassay detection between ImmunoCAP EliA and ACL Acustar. (% of positive patients).]
| Clincal Characteristics of LA positive patients | Number | Triple positivity in agreement | Triple positivity ImmunoCAP alone | Triple positivity Acustar alone |
| APS thrombosis | 13 | 9 (69%) | 0 | 4 (30%) |
| APS pregnancy morbidity | 1 | 1 (100%) | 0 | 0 |
| Non APS thrombosis | 5 | 0 | 0 | 0 |
| Autoimmune Disease | 11 | 0 | 0 | 3 (27%) |
| Total | 30 | 10 (33%) | 0 | 7 (23%) |
[Table 2. Discrepancies in triple positivity detection between ImmunoCAP EliA and ACL Acustar. Number of triple-positives in (dis)agreement. (% of posi]
To cite this abstract in AMA style:
Montaruli B, Romito A, Guiotto C, Bertero T, Sivera P, Cosseddu D. CliA Immunoassay: Better Identification of High Thrombotic Risk Triple Positive Antiphospholipid Patients [abstract]. Res Pract Thromb Haemost. 2020; 4 (Suppl 1). https://abstracts.isth.org/abstract/clia-immunoassay-better-identification-of-high-thrombotic-risk-triple-positive-antiphospholipid-patients/. Accessed October 2, 2023.« Back to ISTH 2020 Congress
ISTH Congress Abstracts - https://abstracts.isth.org/abstract/clia-immunoassay-better-identification-of-high-thrombotic-risk-triple-positive-antiphospholipid-patients/