All issues > Volume 43(3); 2000

Original Article

J Korean Pediatr Soc. 2000;43(3):395-401. Published online March 15, 2000.

Study of Autoantibodies Against Platelet GP IIb/IIIa and GP Ib/IX in Childhood Chronic Idiopathic Thrombocytopenic Purpura

Chanwook CW Woo¹, Junghwa JH Lee¹, Kwangchul KC Lee¹, Soonkyum SK Kim¹

¹Department of Pediatrics, College of Medicine, Korea University, Seoul, Korea

Abstract

Purpose
: Chronic idiopathic thrombocytopenic purpura(CITP) is an autoimmune disease caused by autoantibodies reacting to certain antigens, and platelet glycoprotein(GP) IIb/IIIa and GP Ib/IX complexes are thought to be some of those antigens. However, the clinical significance of anti-GP autoantibodies in CITP patients is unknown. In this study, we investigated the clinical correlation between the presence of circulating autoantibodies against GP IIb/IIIa and GP Ib/IX, and disease activity.
Methods
: From December 1997 to June 1998, 20 CITP patients were enrolled in this study. Autoantibodies against GP IIb/IIIa and GP Ib/IX in patient`s sera during treatment were detected by immunoblotting, and their platelet counts at the initial evaluation and 6 month follow-up were compared according to the presence or the absence of antibodies.
Results
: Autoantibodies to GP antigens were found in 40%(8/20) of the patients. Seven patients were positive for GP IIb/IIIa; 4 for GP Ib/IX and 3 for both. GP autoantibody-positive patients had lower mean platelet counts than GP autoantibody-negative patients at initial evaluation (133,000/μL vs 172,000/μL, P>0.05) and at 6 month follow-up(154,000/μL vs 192,000/μL, P>0.05). Detection of GP autoantibodies related more with active disease than with remission at initial evaluation(45.5%(5/11) vs 33.3%(3/9), P>0.05) and at 6 month follow-up(50.0%(5/10) vs 30.0% (3/10), P>0.05). There was no detection of GP-specific antibodies in 3 splenectomized patients.
Conclusion
: It is hard to conclude on our data alone that the presence of GP autoantibodies correlates with disease status in CITP, although it seems to associate with lower platelet counts.

Keywords :Chronic Idiopathic Thrombocytopenic Purpura, Autoantibody, Glycoprotein IIb/IIIa complex, Glycoprotein Ib/IX complex