Non-transient "self-sustaining" heparin-induced thrombocytopenia: 4-year persistence of a platelet-activating PF4/heparin-antibody status without heparin exposure.
The more we come to understand the pathophysiology of heparin-induced thrombocytopenia (HIT) syndrome, the more we realize that HIT is a rather unusual immune response. One peculiar feature of HIT is the transient character of the antibodies. After cessation of exposure to heparins, the antibodies tend to disappear after 40-100 days. If re-immunization occurs, it generally takes at least 4 days to redevelop antibodies (if they are formed at all). We report about a patient who most likely developed platelet-activating IgG-specific platelet factor 4 (PF4)/heparin antibodies after knee surgery, experienced a transient ischemic attack years later [when HIT was diagnosed by using PF4/heparin ELISA] and presented a high number of these antibodies even 4 years after this first diagnosis of HIT without further re-exposure to heparin.
Institute for Laboratory and Transfusion Medicine, Heart and Diabetes Centre, Ruhr-University Bochum , Bad Oeynhausen , Germany .
Ingvild
I
Birschmann
Jan
J
Gummert
Uwe
U
Schirmer
Cornelius
C
Knabbe
Ulrich J
UJ
Sachs
Andreas
A
Koster
D000368:Aged; D000906:Antibodies / Q000276:immunology*; D006493:Heparin / Q000009:adverse effects*; D006801:Humans; D008297:Male; D015539:Platelet Activation / Q000187:drug effects*; D010978:Platelet Factor 4 / Q000276:immunology*; D013921:Thrombocytopenia / Q000139:chemically induced*
D000906:Antibodies; D010978:Platelet Factor 4; D006493:Heparin
HIT; heparin; platelets