Analysis of idiopathic thrombocytopenic purpura patients with antiglycoprotein IIb/IIIa or Ib autoantibodies.
We analyzed the immunological characteristics of patients with idiopathic thrombocytopenic purpura (ITP) and antiglycoprotein (GP) IIb/IIIa or GPIb autoantibodies. Among 101 ITP patients, 32 had anti-GPIIb/IIIa and 19 had anti-GPIb autoantibodies. Thrombocytopenia was more severe in patients with anti-GPIb autoantibodies than in patients without these autoantibodies, whereas ITP patients with anti-GPIIb/IIIa autoantibodies did not develop severe thrombocytopenia. Patients with anti-GPIb autoantibodies showed significant increases of platelet-associated IgM and platelet-associated C3 in comparison with patients without the autoantibodies, despite there being no significant difference in the platelet-associated IgG levels. The lymphocyte subsets and the blastogenic response in patients with anti-GPIb autoantibodies were also significantly different from those in the patients without these autoantibodies. Furthermore, severe purpura and a poor response to prednisolone were far more common in the patients with anti-GPIb autoantibodies. Activation of the complement system and/or functional abnormalities of lymphocytes thus appear to be involved in the development of thrombocytopenia in ITP patients with anti-GPIb autoantibodies, and such antibodies may be associated with a particularly severe form of ITP.
Nomura
S
S
First Department of Internal Medicine, Kansai Medical University, Osaka, Japan.
Yanabu
M
M
Soga
T
T
Kido
H
H
Fukuroi
T
T
Yamaguchi
K
K
Nagata
H
H
Kokawa
T
T
Yasunaga
K
K
D001323:Autoantibodies / Q000097:blood*; D001792:Blood Platelets / Q000276:immunology; D003176:Complement C3 / Q000378:metabolism; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D007075:Immunoglobulin M / Q000097:blood; D010976:Platelet Count; D010980:Platelet Membrane Glycoproteins / Q000276:immunology*; D016553:Purpura, Thrombocytopenic, Idiopathic / Q000276:immunology*
D001323:Autoantibodies; D003176:Complement C3; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D010980:Platelet Membrane Glycoproteins