A Modified Dithiothreitol Protocol for Eliminating Daratumumab Interference

Nazia Akhtar, Henriette Lorenzen, Vibeke Juul Ljørring, Maria Nielsen, Lea Svendsen

    Publikation: Konferencebidrag uden forlag/tidsskriftPosterForskningpeer review

    Abstract

    Background:
    Daratumumab (DARA) is a monoclonal antibody directed against the glycoprotein CD38, used as treatment for
    patients with Multiple Myeloma. DARA causes interference in serological antibody testing, complicating the detection of clinical
    significant alloantibodies prior to blood transfusion. The interference is eliminated by using dithiothreitol (DTT)-treated reagent red
    blood cells (RBCs). However, a disadvantage of the DTT-method is the time-consuming procedure and the hemolysis observed
    during long-term storage of DTT-treated reagent RBCs.
    To overcome this challenge, the Department of Clinical Immunology, Herlev University Hospital, has developed a modified protocol
    for DTT treatment that improves stability of reagent RBCs by 33 days without any visual hemolysis and ensures detection of
    alloantibodies. This protocol is a modification of AABB´s technical manual due to a reduced amount of DTT used for the treatment
    of reagent RBCs.
    The purpose of the modified protocol was to enable preparation of DTT-treated reagent RBCs in conjunction with regular reagent
    RBCs in order to improve laboratory efficiency and to reduce turnaround time for antibody detection.

    Aims:
    The aim of this study is to validate the modified protocol for DTT treatment of reagent RBCs, and to measure the reduced time
    spent on detection of alloantibodies.

    Methods:
    DTT treatment of reagent RBCs was performed, with DTT supplied by the manufacturer Sigma Aldrich, according to
    AABB´s technical manual except for a RBC:DTT ratio of 30:25 (vol:vol). Multiple batches of DTT-treated reagent RBCs were
    continuously prepared and distributed to three transfusion services in The Capital Region and Region Zealand of Denmark from
    February 2017 to February 2018. Antibody screening tests were performed, at all three study sites, with untreated and DTT-treated
    reagent RBCs on plasma samples from DARA-treated patients (n=50) and on plasma samples (n=60) from patients with known
    clinically significant alloantibodies (n=70). Antibody screening tests were performed using Column Agglutination Technology with
    Coombs anti-IgG ID Cards (BioRad Laboratories).
    Analysis time was measured and compared using both immediately and in advance prepared DTT-treated reagent RBCs.

    Results:
    The outcome of the study showed that DARA interference was eliminated in all 50 samples from DARA-treated patients.
    55 of 70 alloantibodies were detected and the remaining 15 alloantibodies within the Kell system were negative, using the modified
    protocol for DTT-treated reagent RBCs.
    DTT-treated reagent RBCs prepared in advance provided antibody screening test results within 37 minutes compared to 90 minutes
    with immediately prepared DTT-treated reagent RBCs.

    Summary / Conclusions:
    Validation results show, that the modified protocol for DTT-treatment of reagent RBCs eliminates
    DARA interference and detects alloantibodies examined except for alloantibodies within the Kell system.
    DTT-treated reagent RBCs, prepared in advance, reduce antibody detection time by 53 minutes.
    The present study show that a central preparation of DTT-treated reagent RBCs and distribution to transfusion services ensures
    quality, improves laboratory efficiency and therefore prevents delayed blood transfusions.
    OriginalsprogEngelsk
    Publikationsdato2 jun. 2018
    StatusUdgivet - 2 jun. 2018
    Begivenhed35th International Congress of the International Society of Blood Transfusion - Metro Toronto Convention Centre, Toronto, Canada
    Varighed: 2 jun. 20186 jun. 2018
    Konferencens nummer: 35th
    http://www.isbtweb.org/toronto/

    Konference

    Konference35th International Congress of the International Society of Blood Transfusion
    Nummer35th
    LokationMetro Toronto Convention Centre
    Land/OmrådeCanada
    ByToronto
    Periode02/06/1806/06/18
    Internetadresse

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