Quantification of platelet-associated IgG for differential diagnosis of patients with thrombocytopenia.
Immune thrombocytopenia is due to platelet destruction by circulating glycoprotein-specific antibodies and is found in various disorders. Methods for the detection of platelet-associated IgG (PAIgG) are generally sensitive but unspecific, whereas glycoprotein-specific assays are highly specific but less sensitive. Usefully, a sensitive screening method for PAIgG detection would also provide information for differential diagnosis. We developed a quantitative direct Platelet Immunofluorescence Test (PIFT) by flow cytometry and studied 79 thrombocytopenic patients with immune thrombocytopenia and other disorders. The sensitivity of the assay was 94%, its specificity 66% for the detection of a clinically obvious immune thrombocytopenia. PAIgG levels of patients with immune thrombocytopenia differed significantly from those of other patients with low platelet counts (p <0.001). The quantitative PIFT proved to be a sensitive method for PAIgG detection and should therefore be used as a screening method. In addition, it could be helpful for differential diagnosis in marked thrombocytopenia where a MAIPA is not feasible.
Hagenström
H
H
Institute of Immunology and Transfusion Medicine, University of Lübeck School of Medicine, Germany. hagenstroem@immu.mu-luebeck.de
Schlenke
P
P
Hennig
H
H
Kirchner
H
H
Klüter
H
H
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001323:Autoantibodies / Q000097:blood / Q000276:immunology; D001792:Blood Platelets / Q000276:immunology*; D003937:Diagnosis, Differential; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D016553:Purpura, Thrombocytopenic, Idiopathic / Q000097:blood / Q000175:diagnosis* / Q000276:immunology
D001323:Autoantibodies; D007074:Immunoglobulin G