PB0093 - Antiphospholipid antibodies in convalescent plasma of donors recovered from mild COVID-19

Sunday, June 25, 2023

18:30 – 19:30 ET

Room: Exhibition

Presenting Author(s)

DB

Dorit Blickstein, MD (she/her/hers)

Senior Physician, Thrombosis and Hemostasis Service
Hematology, Shamir Medical Center
zerifin, Tel Aviv, Israel

Co-Author(s)

MI

Marina Izak

Senior Physician
Magen David Adom National Blood Services
Ramat Gan, Tel Aviv, Israel
TF

Talia Filipovich- Rimon

deputy director
Hematology laboratory, Shamir Medical Center, Israel
Zerifin, Tel Aviv, Israel
OG

Osnat Garach- Jehoshua Garach- Jehoshua

Director
Hematology laboratory, Shamir Medical Center, Israel
Zerifin, Tel Aviv, Israel
NR

Naomi Rahimi- Levene

Director
Blood bank, Shamir Medical Center, Israel
Zerifin, Tel Aviv, Israel
ES

Eilat Shinar

Director
Magen David Adom National Blood Services, Ramat Gan, Israel
Ramat Gan, Tel Aviv, Israel
RA

Ramzia Abu Hamad

Director
Clinical Chemistry Laboratory, Shamir Medical Center, Israel
Zerifin, Tel Aviv, Israel
AB

Adina Bar- Chaim

Director
Clinical laboratories, Shamir Medical Center, Israel
Zerifin, Tel Aviv, Israel
MK

Maya Koren-Michowitz

Director
Department of Hematology, Shamir Medical Center, Israel
Zerifin, Tel Aviv, Israel

Background: Passive immunization by the infusion of convalescent plasma (CP) obtained from patients who have recently recovered from COVID-19, thus having antibodies to SARS-CoV-2, is a potential strategy to reduce the severity of illness. High prevalence of antiphospholipid antibodies (APLA) in patients with COVID-19 has been reported during the pandemic, raising a concern whether the use of CP could increase the risk of thrombosis in transfused patients.

Aims: To evaluate the prevalence of APLA in COVID-19 CP (CCP) in order to assess the potential prothrombotic influence of transfused CCP to COVID-19 patients.

Methods: We studied the prevalence of APLA in 122 CCP samples collected from healthy donors who recovered from mild COVID-19, at 2 time periods: September 2020 to January 2021 (defined as "early period" samples) and April to May 2021 (defined as "late period" samples). Thirty-four healthy subjects unexposed to COVID-19 were used as controls.

Results: APLA were present in 6% of CCP samples compared to 18% in controls, p=0.026. In the CCP group, one donor had anti-β2GP1 IgG, one anti-β2GP1 IgM and five had LAC SCT, all in "late period" donors. In the control group one subject had anti-β2GP1 IgG, two LAC dRVVT and four LAC SCT (both LAC SCT and LAC dRVVT in one subject). The repeated test in the control group done after 3-5 months demonstrated a much lower prevalence (3.22%).

Conclusion(s): The low prevalence of APLA in CCP donors reassures the safety of CCP administration to patients with severe COVID- 19, in terms of thrombosis inducing risk. Using CCP from younger donors might be preferable because of a trend for higher prevalence of APLA in older compared to younger CCP donors. The higher prevalence of APLA in healthy controls is intriguing and should be further investigated.