A perspective on the measurement of ADAMTS13 in thrombotic thrombocytopaenic purpura.
The recent discovery of the von Willebrand Factor (vWF) cleaving protease (ADAMTS13) and the association of its deficiency with thrombotic thrombocytopaenic purpura (TTP) has generated both enormous interest and considerable confusion. Ultra large von Willebrand Factor (UL vWF) multimers are present in the plasmas of patients with chronic relapsing TTP in remission but disappear during an attack. This observation led to the recognition that UL vWF multimers precipitate the thrombotic occlusion of arterioles, a feature that characterizes TTP. Multiple mutations in ADAMTS13 are associated with congenital TTP and neutralizing autoantibodies have been demonstrated in the acquired TTP syndrome. Although a number of functional assays for this enzyme have been described, the more rigorously evaluated assays are difficult to perform outside a research laboratory. There is also an enduring uncertainty about the specificity of ADAMTS13 deficiency for the diagnosis of acquired TTP and a perception that the result does not alter patient management. The cloning of the ADAMTS13 gene has also raised the prospect of recombinant enzyme therapy for the treatment of TTP, and this has heightened the need for a simple assay. In this review, we evaluate the value of measuring this enzyme in the management of TTP.
Pimanda
John E
JE
The University of New South Wales and The Department of Haematology, The Prince of Wales Hospital, Sydney, Australia. jpimanda@unsw.edu.au
Chesterman
Colin N
CN
Hogg
Philip J
PJ
D051722:ADAM Proteins; D000071120:ADAMTS13 Protein; D001323:Autoantibodies / Q000276:immunology; D001327:Autoimmune Diseases / Q000276:immunology; D017609:Barium Compounds / Q000494:pharmacology; D001704:Biopolymers; D001797:Blood Protein Electrophoresis; D002122:Calcium Chloride / Q000494:pharmacology; D019090:Case Management; D002712:Chlorides / Q000494:pharmacology; D004796:Clinical Enzyme Tests / Q000379:methods*; D004587:Electrophoresis, Agar Gel; D004591:Electrophoresis, Polyacrylamide Gel; D004789:Enzyme Activation / Q000187:drug effects; D018056:Hemorheology; D006801:Humans; D008666:Metalloendopeptidases / Q000097:blood* / Q000737:chemistry / Q000172:deficiency / Q000235:genetics / Q000276:immunology; D018715:Microscopy, Video; D020125:Mutation, Missense; D010446:Peptide Fragments / Q000097:blood; D010974:Platelet Aggregation; D011697:Purpura, Thrombotic Thrombocytopenic / Q000175:diagnosis* / Q000235:genetics / Q000276:immunology / Q000628:therapy; D012008:Recurrence; D014841:von Willebrand Factor / Q000032:analysis* / Q000378:metabolism
D001323:Autoantibodies; D017609:Barium Compounds; D001704:Biopolymers; D002712:Chlorides; D010446:Peptide Fragments; D014841:von Willebrand Factor; C024986:barium chloride; D051722:ADAM Proteins; D008666:Metalloendopeptidases; D000071120:ADAMTS13 Protein; C099604:ADAMTS13 protein, human; D002122:Calcium Chloride