(P-HC-8) ADAMTS13 levels in liquid plasma: A potential therapeutic option for patients with thrombotic thrombocytopenic purpura

Sunday, October 20, 2024

12:00 PM - 1:00 PM

Presenting Author(s)

WC

Wenjing Cao, MD/PhD (she/her/hers)

Residency Program, Department of Pathology and Laboratory Medicine, University of Wisconsin Hospitals and Clinics
Madison, Wisconsin, United States

Background/Case Studies: Severe deficiency of ADAMTS13 activity is associated with thrombotic thrombocytopenic purpura (TTP), with thawed plasma (TP) being the primary product used in TTP management. Liquid plasma (LP), derived from whole blood donations and stored at 4 °C without freezing, shares the same expiration as the corresponding unit of whole blood. LP primarily serves as a bridge to TP for emergency transfusions. While the efficacy of coagulation profiles in TP and LP is well-documented, there is limited information on the stability of ADAMTS13 activity during the shelf life of these products.

Study

Design/Methods: Ten units of LP from distinct whole blood donations were collected on day 27. Ten units of TP from products frozen within 24 hours (PF24) were also collected on day 6. One unit of LP isolated from whole blood within 5 days of collection underwent longitudinal sampling until day 30, with the initial collection designated as day 0. Samples were stored at -80°C until ready for assays. ADAMTS13 activity was assessed using fluorescence resonance energy transfer (FRETS) assay with the cattle von Willebrand factor (VWF)-71 fluorogenic substrate, and a subset was repeated using a clinical ELISA-based assay. Data were presented as mean ± standard deviation (SD), and Student’s t-test was used for statistical analysis, with a p-value < 0.05 considered statistically significant.

Results/Findings:

The average level of ADAMTS13 activity in 10 LP units was 0.97 ± 0.14 IU/mL by FRETS assay, with a median of 0.967 IU/mL (range: 0.79 to 1.22 IU/mL). For 10 TP units, the average level of ADAMTS13 activity was 0.89 ± 0.13 IU/mL with a median of 0.91 IU/mL (range: 0.63 to 1.05 IU/mL). No statistically significant difference was observed between the two products regarding the ADAMTS13 activity on day 1 post-expiration (p=0.1717). ADAMTS13 activity in LP consistently remained stable without decline over the 30-day observation. ELISA results were consistent with FRETS assay findings.

Conclusions: Both liquid plasma and thawed plasma exhibit comparable and sustained ADAMTS13 activity throughout their shelf-life. ADAMTS13 activity in LP remains stable for up to 30 days of storage at 4°C, suggesting that LP may be a potential alternative to TP for treating thrombotic thrombocytopenic purpura.