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Inhibitory Anti Adamts13 Antibodies with a New Rapid Fully Automated Clia Assay

1AO Ordine Mauriziano, Torino, Italy, 2Legnano General Hospital, Blood Transfusion Center, Legnano (Mi), Italy, 3AO San Giovanni Bosco, Center for Research of Immunopathology and Rare Diseases, Turin, Italy, 4AOU Città della Salute e della Scienza, Laboratory of the Regional Reference Center for Adult Thrombotic and Hemorrhagic Diseases, Turin, Italy, 5AO Ordine Mauriziano, SC Laboratory Analysis, Turin, Italy

Abstract Number: PB1887

Meeting: ISTH 2020 Congress

Theme: Thrombotic Microangiopathies » ADAMTS13 and TTP

Background: Thrombotic thrombocytopenic purpura (TTP) is a life-threatening disorder, characterised by severe deficiency of ADAMTS13 activity associated with autoantibodies to ADAMTS13. Noninhibitory and inhibitory autoantibodies can be detected with an enzyme-linked immunosorbent assay (ELISA); Bethesda Assay can identify the subset of inhibitory autoantibodies. Recently, a chemiluminescence (CliA) ADAMTS13 activity (HemosIL Acustar ADAMTS13 activity, IL, USA) because of its short turnaround time, full automation and good performances has been demonstrated to be the first choice for the diagnosis of TTP in emergency settings.

Aims: Aim of this study was to analyze the performances of CliA ADAMTS13 activity assay detecting inhibitory anti-ADAMTS13 antibody by using Bethesda Assay.

Methods: A method comparison study was performed on 32 samples stored by 4 Italian hospital between 2014 to 2019: 8 acute TTPs, 9 TTPs follow-up, 4 TTPs relapse, 1 congenital TTP, 4 HUS, 1 atypical HUS, 4 suspected but not confirmed TTPs. We retrived results of test previously run in ELISA for both activity and autoantibodies (Technozym Adamts13 Activity and INH, Technoclone Gmbh, Austria). We then rerun at the same time new tests on thawed frozen samples: ELISA and CliA activity, ELISA autoantibodies, and ELISA and CliA Bethesda assays.

Results: We found a very good correlation between ELISA and CliA activity assays results (r=0.96) and between archived ELISA and CliA activity results (r=0.93). Both correlation were better than the one obtained between historical and newly performed ELISA results (r=0.92). Agreement between the anti-ADAMTS13 assays performed ranged from moderate to very good (Table1).
Table 1. Kappa …

Conclusions: CliA and ELISA Bethesda assays showed very good agreement with samples run at the same time using ELISA anti-ADAMTS13 autoantibodies assay. CliA Bethesda assay allowed identification of inhibitory anti-ADAMTS13 within almost same turnaround time of ELISA, but with better automation; the only manual operations needed were sample mixing and two incubations.

  ELISA autoantibodies newly performed ELISA autoantibodies newly performed CliA Bethesda Assay
ELISA autoantibodies historical archive data – – –
ELISA autoantibodies newly performed 0.50 – –
CliA Bethesda Assay 0.68 0.86 –
ELISA Bethesda Assay 0.58 0.80 0.93

[Table 1. Kappa Cohen coefficients obtained by comparing anti-ADAMTS13 antibodies]

To cite this abstract in AMA style:

Montaruli B, Novelli C, Solfietti L, Valpreda A, Bazzan M, Beverina IL, Roccatello D, Cosseddu D. Inhibitory Anti Adamts13 Antibodies with a New Rapid Fully Automated Clia Assay [abstract]. Res Pract Thromb Haemost. 2020; 4 (Suppl 1). https://abstracts.isth.org/abstract/inhibitory-anti-adamts13-antibodies-with-a-new-rapid-fully-automated-clia-assay/. Accessed September 25, 2023.

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