ADAMTS13 content and VWF multimer and triplet structure in commercially available VWF/FVIII concentrates

Area of Science:

• Biochemistry
• Hematology
• Protein analysis

Background:

• ADAMTS13 is a metalloproteinase crucial for cleaving von Willebrand factor (VWF) into smaller multimers.
• This cleavage influences VWF multimeric size and triplet band distribution, vital for VWF function.
• Understanding ADAMTS13 levels in VWF/FVIII concentrates is important for assessing product quality and clinical efficacy.

Purpose of the Study:

• To analyze ADAMTS13 content, VWF multimeric size distribution, and VWF triplet structure in five commercial VWF/FVIII concentrates.
• To investigate the correlation between ADAMTS13 levels and VWF structural characteristics in these concentrates.

Main Methods:

• Analysis of ADAMTS13 antigen and activity levels in VWF/FVIII concentrates.
• Assessment of VWF multimeric size distribution using electrophoresis.
• Densitometric quantification of VWF triplet band structure.

Main Results:

• ADAMTS13 antigen/activity ratios varied among concentrates, with Fanhdi® and Haemate HS® showing higher levels.
• ADAMTS13 levels did not correlate with high molecular weight VWF multimer content.
• A correlation was observed between higher ADAMTS13 content and an altered VWF triplet distribution (enhanced faster migrating band).
• Wilate®, Immunate®, and Willfact® exhibited plasma-like VWF triplet distribution with lower ADAMTS13 levels.

Conclusions:

• Commercial VWF/FVIII concentrates differ in their ADAMTS13 content and VWF triplet structure.
• Higher ADAMTS13 levels in Fanhdi® and Haemate HS® are associated with an altered VWF triplet structure.
• These findings suggest potential implications for the functional performance and clinical efficacy of VWF/FVIII concentrates.