We use cookies to understand how you use our site and to improve your experience. This includes personalizing content and advertising. To learn more, click here. By continuing to use our site, you accept our use of cookies. Cookie Policy.

Features Partner Sites Information LinkXpress
Sign In
Advertise with Us
Abbott Diagnostics- Hematology Division

Download Mobile App




Events

ATTENTION: Due to the COVID-19 PANDEMIC, many events are being rescheduled for a later date, converted into virtual venues, or altogether cancelled. Please check with the event organizer or website prior to planning for any forthcoming event.
27 Oct 2021 - 29 Oct 2021

Pathogenic Antibodies Decline Over Time in VITT

By LabMedica International staff writers
Posted on 25 Sep 2021
Print article
Vaccine-induced immune thrombotic thrombocytopenia (VITT) has been described after vaccination with the adenoviral vector vaccines and can be confirmed by anti–PF4–heparin IgG enzyme-linked immunosorbent assay (Photo courtesy of Arne Müseler)
Vaccine-induced immune thrombotic thrombocytopenia (VITT) has been described after vaccination with the adenoviral vector vaccines and can be confirmed by anti–PF4–heparin IgG enzyme-linked immunosorbent assay (Photo courtesy of Arne Müseler)
Vaccine-induced immune thrombotic thrombocytopenia (VITT) has been described after vaccination with the adenoviral vector vaccines. A syndrome characterized by venous or arterial thrombosis, particularly at unusual sites including cerebral sinus venous thrombosis (CSVT)/splanchnic thrombosis, and mild to severe thrombocytopenia.

VITT is caused by platelet-activating anti–platelet factor 4 (PF4) IgG antibodies, the presence of which can be confirmed by anti–PF4–heparin IgG enzyme-linked immunosorbent assay (ELISA) in combination with PF4-enhanced washed-platelet–activation assays. Clinical and in vitro characteristics of acute VITT closely resemble (autoimmune) heparin-induced thrombocytopenia.

Medical Scientists at the Universitätsmedizin Greifswald (Greifswald, Germany) conducted a study involving 35 patients with serologically confirmed VITT (27 women and eight men; median age, 53 years [range, 18 to 77 years]). The patients’ clinical symptoms started between days five and 18 after vaccination. All the patients presented with thrombocytopenia, and 30 presented with thrombosis.

Anti-PF4 IgG antibodies were tested by PF4/heparin ELISA. The cut-off of the ELISA was defined as optical density (OD) 0.5; samples testing >0.5 - 1.0 were defined as positive, between >1.0 - 2.0 as strongly–positive; greater 2.0 OD were defined as very strongly positive. Platelet activation by the antibodies was tested in a PF4-dependent washed platelet assay. Negatively tested sera were repeated with a new panel of washed platelets on a different day. A positive result was defined as PF4-dependent activation of platelets (lag time, <30 min) of at least two of three different donors.

The scientists reported that results of the PF4-dependent platelet-activation assay became negative in 23 of 35 patients (66%). In 14 of the 15 patients (93%), with follow-up of more than 12 weeks the platelet-activation assay became negative within a median of 12 weeks. In addition, the median optical density on anti–PF4–heparin IgG ELISA declined by 53% between the first and last available blood samples (median optical density, 2.98 versus 1.39). However, full seroreversion to a negative ELISA result (i.e., an optical density of <0.5) was seen in only three patients. In one patient, PF4-dependent platelet-activating antibodies and ELISA optical density values of greater than 3.0 persisted for more than 12 weeks in association with recurrent episodes of thrombocytopenia.

The authors reported that to achieve full protection against coronavirus disease 2019 (Covid-19), a second vaccination is needed after a first dose of ChAdOx1 nCoV-19. On the basis of their small series of patients, subsequent vaccination with an mRNA vaccine appears to be safe after results of platelet-activation assays for VITT antibodies have become negative. When no platelet-activation assay is available, a substantial decline in the optical density on anti–PF4–heparin IgG ELISA may be used as a decision criterion. The study was published on September 8, 2021 in The New England Journal of Medicine.

Related Links:

Universitätsmedizin Greifswald

New
Gold Supplier
Pipette Tips
Sapphire Pipette Tips
New
Automated Urinalysis Solution
DxU Iris Workcell
New
Gold Supplier
BMP Whole Blood Analyzer
GEM Premier ChemSTAT
New
Clinical Chemistry Reagents
SEKURE Clinical Chemistry Reagents

Print article

Channels

Hematology

view channel
Image: Psoriatic plaques, showing a silvery center surrounded by a reddened border (Photo courtesy of Jane Bianchi, BA)

Hematological Parameters Compared in Psoriasis Patients

Psoriasis is a chronic, immune-mediated disorder that can involve the skin and/or joints. Four clinical types of psoriasis are currently recognized: psoriasis vulgaris (PsV), pustular psoriasis (PP), erythrodermic... Read more

Microbiology

view channel
Illustration

Sysmex Inostics Launches New Ultra-Sensitive Leukemia Blood Test for Early Detection of Cancer Cells Following Initial Therapy

Sysmex Inostics (Baltimore, MD, USA) has developed a new CLIA-validated liquid biopsy test for the detection of Minimal Residual Disease (MRD) in Acute Myeloid Leukemia (AML) to better help in the fight... Read more

Technology

view channel
Image: QIAreach QuantiFERON-TB (Photo courtesy of QIAGEN N.V.)

Qiagen Launches Novel Tuberculosis Blood Test That Marks Quantum Leap from Traditional TB Skin Test

QIAGEN N.V. (Venlo, Netherlands) has announced the launch and CE marking of QIAreach QuantiFERON-TB test for tuberculosis (TB) infection, in order to help achieve global TB elimination targets by increasing... Read more

Industry

view channel
Image: GastroPanel Quick Test (Photo courtesy of Biohit Healthcare)

Biohit’s Innovative GastroPanel Quick Test Receives CE Mark

Biohit Healthcare’s (Helsinki, Finland) GastroPanel Quick Test, the latest innovation in its unique GastroPanel product family, is now CE marked. The GastroPanel Quick Test is intended for diagnosing... Read more
Copyright © 2000-2021 Globetech Media. All rights reserved.