von Willebrand factor mediates increased platelet retention in recurrent thrombotic thrombocytopenic purpura

• The plasma cryoprecipitate of two brothers with recurrent thrombotic thrombocytopenic purpura (TTP) was previously found to mediate increased platelet retention and contain ultra-large von Willebrand factor (vWF) multimers during remissions. We conducted this study to examine if vWF is involved in the increased platelet retention in TTP. Platelet retention decreased when the patients' plasma was incubated with a monoclonal antibody directed to the vWF epitope which interacts with the platelet receptor glycoprotein Ib or when incubated with a Fab-fragment directed to the platelet receptor glycoprotein IIb/IIIa. Replacement of patient vWF with an equivalent concentration of a factor VIII/vWF concentrate containing no ultra-large vWF multimers was accompanied by a normalization of platelet retention. These results indicate that vWF is involved in the increased platelet retention. Analysis of polymorphic markers in the vWF gene demonstrated that a recessive mutation in this gene is unlikely.

Subject headings

MEDICIN OCH HÄLSOVETENSKAP  -- Klinisk medicin -- Hematologi (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Clinical Medicine -- Hematology (hsv//eng)

MEDICIN OCH HÄLSOVETENSKAP  -- Klinisk medicin -- Pediatrik (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Clinical Medicine -- Pediatrics (hsv//eng)

Keyword

Adolescent

Adult

Antibodies, Monoclonal

Blood Platelets

Child

Child, Preschool

Cryoglobulins

Female

Freezing

Genes

Humans

Male

Pedigree

Plasma

Platelet Count

Polymorphism, Genetic

Purpura, Thrombotic Thrombocytopenic

Recurrence

Structure-Activity Relationship

von Willebrand Factor

Publication and Content Type

art (subject category)

ref (subject category)