Normal levels of ADAMTS13 and factor H are present in the pharmaceutically licensed plasma for transfusion (Octaplas®) and in the universally applicable plasma (Uniplas) in development

Background and Objectives The pathomechanism of thrombotic thrombocytopenic purpura (TTP) and atypical haemolytic uraemic syndrome (aHUS) is associated with a severe deficiency of ADAMTS13 and factor H. The aim of this study was to quantify the levels of ADAMTS13 and factor H in the pharmaceutically licensed plasma for transfusion, Octaplas®, and the universally applicable plasma, Uniplas (development product, working title). Furthermore, Octaplas® batches of blood groups A, B, O, AB, and plasmas derived from different sources were compared. Materials and Methods Twenty-four Octaplas® and three Uniplas batches were selected for the study. ADAMTS13 activities were measured by fluorescence resonance energy transfer assay, ADAMTS13 antigen levels were quantified using enzyme-linked immunosorbent assay test kit, while factor H antigen levels were detected using radial immunodiffusion (RID) methods. In addition, von Willebrand factor (vWF) multimeric analyses were performed. Results Both Octaplas®, produced from US and European plasma of different blood groups, and Uniplas contain ADAMTS13 antigen and activity levels as well as factor H concentrations at normal levels without significant differences. In addition, Octaplas® and Uniplas show a vWF multimeric pattern comparable to normal plasma. Conclusion The study revealed that Octaplas® and Uniplas contain normal levels of ADAMTS13 at low batch-to-batch variations. Therefore, both products can substitute the missing or neutralized protease activity in TTP patients and thereby limit vWF-dependent (platelet-related) thrombosis. In addition, both plasma products contain factor H at a physiological level, and, thus can be used efficiently in the treatment of aHUS patients, which have been shown to benefit from plasma administration.