Anti-alphavbeta3 antibodies in chronic immune thrombocytopenic purpura.
In chronic immune thrombocytopenic purpura (ITP), anti-GPIIb-IIIa (alphaIIbbeta3) autoantibodies have been detected in serum and/or platelet-associated IgG (PAIgG) and considered as one of the major causes. We examined whether anti-alphavbeta3 antibodies might be present in ITP cases because of the similarity between alphavbeta3 and GPIIb-IIIa (alphaIIbbeta3). Modified antigen capture ELISA (MACE) using human umbilical vein endothelial cells (HUVEC) showed the presence of serum anti-alphavbeta3 antibodies in 23 of 80 ITP patients (29%). Cross-adsorption studies between platelets and HUVEC demonstrated that most of anti-alphavbeta3 and anti-GPIIb-IIIa antibodies exclusively reacted with alphavbeta3 and GPIIb-IIIa, respectively. Platelet-associated anti-GPIIb-IIIa antibodies did not react with alphavbeta3, either. Interestingly, patients having anti-alphavbeta3 antibodies showed significantly lower platelet counts than negative patients. These results indicate the serum anti-alphavbeta3 antibodies are different ones from the classical anti-GPIIb-IIIa (alphaIIbbeta3) antibodies and would provide a new insight into the pathophysiology of ITP as well as the autoantigenic epitopes on beta3 integrins.
Kosugi
S
S
Department of Internal Medicine and Molecular Science, Graduate School of Medicine, Osaka University, Suita, Japan.
Tomiyama
Y
Y
Honda
S
S
Kashiwagi
H
H
Shiraga
M
M
Tadokoro
S
S
Kiyoi
T
T
Kurata
Y
Y
Matsuzawa
Y
Y
D001323:Autoantibodies / Q000097:blood; D001792:Blood Platelets / Q000378:metabolism; D003429:Cross Reactions / Q000276:immunology; D003601:Cytotoxicity Tests, Immunologic; D004730:Endothelium, Vascular / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D008297:Male; D010976:Platelet Count; D019039:Platelet Glycoprotein GPIIb-IIIa Complex / Q000276:immunology; D016553:Purpura, Thrombocytopenic, Idiopathic / Q000276:immunology*; D019030:Receptors, Vitronectin / Q000276:immunology*; D014471:Umbilical Veins / Q000166:cytology
D001323:Autoantibodies; D019039:Platelet Glycoprotein GPIIb-IIIa Complex; D019030:Receptors, Vitronectin