POS1238 ANTIPHOSPHOLIPID ANTIBODIES AND COVID-19: TREND OVER TIME
Authors: S. Mancuso, S. Truglia, A. Capozzi, F. Pasquali, S. Recalchi, G. Riitano, F. R. Spinelli, M. Sorice, R. Misasi, C. Alessandri, C. M. Mastroianni, F. Conti
Journal: Annals of the Rheumatic Diseases (2021)

Background: Since the beginning of the SARS-CoV-2 outbreak, antiphospholipid antibodies (aPL), a known thrombotic risk factor, have been studied in COVID-19 patients, in whom thromboembolic events have been associated with poor prognosis. To date, the pathogenetic role of aPL and the trend over time is still unknown. Objectives: Aim of the study was to investigate whether aPL positivity was correlated with thrombosis in COVID-19 patients and whether it was a transient or persistent. Methods: We included all consecutive COVID-19 patients hospitalized at Policlinico Umberto I, Sapienza University of Rome from April 1, 2020 to June 7, 2020. In these patients, serum levels of anti-cardiolipin (aCL) IgM, IgG, IgA, anti-β2glycoprotein I (aβ2GPI) IgM, IgG were measured by enzyme-linked immunosorbent assay (ELISA) and Lupus Anticoagulant (LA) was detected with coagulatory tests in patients not in treatment with anticoagulant drugs. Results: Five out of 73 (6.8%) patients resulted positive for aCL IgM, 3 of them also tested positive for aβ2GPI IgM. aCL IgA were tested positive in 14 out of 46 patients (30.4%). Overall 18 patients resulted positive for at least one test. Seven (9.6%) patients developed thrombotic events during hospitalization, 3 of them resulting positive for aPL (Table 1. below). Table 1. Clinical and demographic features of the 7 Covid-19 patients that presented thrombotic events Features Patient 1 Patient 2 Patient 3 Patient 4 Patient 5 Patient 6 Patient 7 Age - yr 67 78 83 43 70 74 95 Sex female female female male male female male Medical History Malignancy, Hypertension Stroke Chronic obstructive pulmonary disease No medical history Chronic obstructive pulmonary disease, Hypertension Malignancy, Hypertension Initial findings Signs and symptoms Dyspnea Dyspnea Dyspnea Fever, ageusia/anosmia, chest pain Fever, cough Dyspnea Dyspnea HRCT chest: Bilateral ground glass opacity yes yes yes yes yes yes yes Baseline laboratory values Lymphocyte count, cells x 10 6 /L 220 210 2330 1580 1680 600 1390 Lactate dehydrogenase, U/L 223 321 199 227 226 349 199 Ferritin mcg/L 614 317 213 387 462 2455 197 D-dimer mcg/L 730 1213 2912 282 688 1298 1097 PaO2:FIO2, mm Hg 132 120 442 534 348 493 314 Anticoagulant therapy at the time of the thrombotic event Therapeutic dosage Prophylactic dosage Prophylactic dosage Not administered Therapeutic dosage Therapeutic dosage Therapeutic dosage Thrombotic events Stroke Pulmonary embolism Peripheral venous thrombosis Myocardial infarction Pulmonary embolism Myocardial infarction, peripheral arterial thrombosis, peripheral venous thrombosis Peripheral venous thrombosis Antiphospholipid antibodies negative Anti-cardiolipin IgM low title, anti-β2glicoprotein I IgM low title negative negative negative Anti-cardiolipin IgM low title, anti-β2glicoprotein I IgM low title Anti-cardiolipin IgA low title Outcome Exitus Exitus Suicide Discharged Discharged Discharged Exitus Antiphospholipid antibodies tested after at least 12 weeks NP NP NP NP NP Negative NP We observed that patients showing double positivity for aCL IgM and aβ2GPI IgM had a likelihood positive ratio of 6.3 for thrombotic events (p=0.012) and a likelihood positive ratio of 4.9 for increased D-dimer levels (p=0.027). aCL IgA, the most prevalent aPL in this cohort, was not associated with thrombosis. Of the 18 aPL positive patients, 5 died, 3 were lost to follow-up, and 10 were tested on a second occasion at least 12 weeks, two patients confirmed positivity without clinical signs suggestive of APS. Conclusion: These results suggest that double positivity for aCL and aβ2GPI IgM increases the risk of thrombosis in COVID-19 patients, unlike aCL IgA. APL positivity may be persistent and it is advisable to monitor it over time. Disclosure of Interests: None declared