Biomed Pap Med Fac Univ Palacky Olomouc Czech Repub. 2023, 167(3):254-262 | DOI: 10.5507/bp.2022.003

Levels and avidities of antiphosphatidylethanolamine antibodies in patients with thrombotic events and immunologically-mediated diseases

Oliver Kuchar^{1, 2}, Milada Petrackova¹, Marta Kalousova¹, Libuse Noskova¹, Tomas Zima¹, Lenka Fialova^{1, 3}

¹ Institute of Medical Biochemistry and Laboratory Diagnostics, First Faculty of Medicine, Charles University and General University Hospital in Prague, Czech Republic

² Thomayer University Hospital, Czech Republic

³ Department of Health Care and Population Protection, Faculty of Biomedical Engineering, Czech Technical University in Prague, Czech Republic

Aims: Antiphosphatidylethanolamine antibodies (aPE) represent one type of antiphospholipid antibody (aPL) directed against the neutral phospholipids - phosphatidylethanolamines. The aim of this study was to evaluate levels and avidities of aPE in several groups of patients and compare them with conventional aPLs.

Methods: aPE were analysed in a cohort consisting of 68 hospitalized patients. The other cohort comprised 22 patients with immunologically-mediated diseases. The control group consisted of 20 healthy persons. ELISA methods were used for determination of aPL. Avidities of aPE were tested by modified ELISA with urea as a chaotropic agent.

Results: aPE IgG/IgM were significantly higher in the group of patients with venous thromboembolism than those with non-thrombotic internal disorders (P=0.02 for both Ig classes). aPE IgG/IgM elevated above cut-off values were found in 10.8% of patients with venous thromboembolism and as a single aPL in 6.5%. Levels of aPE IgG higher than our limit (>6 U/mL) were detected in 29% of patients with immunologically-mediated diseases with other positive aPL. Low-, intermediate- and high-avidity aPE IgG were found in patients of both cohorts. The avidities of aPE IgG differed from those of anticardiolipin antibodies IgG. Neither aPE IgG levels nor avidity dynamics significantly changed during follow-up.

Conclusion: aPE may be related to venous thromboembolism and may be part of the repertoire of aPL in immunologically-mediated diseases. There are patients with thrombosis negative for conventional aPL but positive for aPE. aPE IgG may have different avidities.

Keywords: anticardiolipin antibodies, antiphosphatidylethanolamine antibodies, avidity, ELISA, chaotropic agents, urea, thrombosis, systemic lupus erythematosus

Received: October 14, 2021; Revised: January 24, 2022; Accepted: January 25, 2022; Prepublished online: February 11, 2022; Published: September 21, 2023  Show citation