Specific quantification of heparin-dependent antibodies for the diagnosis of heparin-associated thrombocytopenia using an enzyme-linked immunosorbent assay.
In order to specifically detect heparin-dependent antibodies in patients with suspected heparin-associated thrombocytopenia (HAT), an adapted ELISA test was developed. Serum-platelet bindable IgG (SPb-IgG) were measured in the absence and in the presence of heparin in the sera from a/ 25 normal controls, 25 patients treated by heparin without thrombocytopenia, 29 thrombocytopenic patients not receiving heparin and b/ 12 patients with confirmed HAT. In the absence of heparin, the 12 HAT sera showed normal or elevated SPb-IgG levels (range = 10.4-36 Arbitrary Units or AU) as compared to healthy controls (8-17.1 AU). After coincubation of HAT sera with heparin (0.25, 0.50, 0.75, and 1 IU/ml), SPb-IgG levels were consistently elevated (range = 22.8-150 AU), and this increase in IgG binding (equal in mean to 200%) was always inhibited with 5 IU/ml of heparin. In contrast, a mean maximum increase in SPblgG levels of only 20% was registered in all control groups whatever the tested heparin concentration. Thus, this ELISA allows the specific diagnosis of HAT by demonstrating a serum IgG binding on platelets only in the presence of therapeutic concentrations of heparin.
Gruel
Y
Y
Laboratoire d'Hématologie, Faculté de Médecine, Tours, France.
Rupin
A
A
Darnige
L
L
Moalic-Reverdiau
P
P
Poumier-Gaschard
P
P
Binet
C
C
Bardos
P
P
Leroy
J
J
D000368:Aged; D000369:Aged, 80 and over; D000906:Antibodies / Q000097:blood*; D001792:Blood Platelets / Q000276:immunology; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D005069:Evaluation Studies as Topic; D005260:Female; D006493:Heparin / Q000009:adverse effects / Q000276:immunology*; D006801:Humans; D007074:Immunoglobulin G / Q000032:analysis; D008297:Male; D013921:Thrombocytopenia / Q000175:diagnosis* / Q000209:etiology / Q000276:immunology
D000906:Antibodies; D007074:Immunoglobulin G; D006493:Heparin