Two types of autoantibody-mediated thrombocytopenia in patients with systemic lupus erythematosus.

Abstract

OBJECTIVES:

To determine whether autoantibodies to two platelet-specific antigens, glycoprotein IIb/IIIa (GPIIb/IIIa) and thrombopoietin receptor (TPOR), contribute to thrombocytopenia in patients with systemic lupus erythematosus (SLE).

METHODS:

Circulating B cells producing anti-GPIIb/IIIa antibodies and serum anti-TPOR antibodies were measured in 32 SLE patients with thrombocytopenia, 30 SLE patients without thrombocytopenia, 92 patients with idiopathic thrombocytopenia and 60 healthy controls. The megakaryocyte density in bone-marrow smears from all the patients with thrombocytopenia was evaluated.

RESULTS:

Anti-GPIIb/IIIa and anti-TPOR antibody responses were more frequent in SLE patients with thrombocytopenia than in those without thrombocytopenia (88 vs 17%, P<0.0001; and 22% vs 0%, P=0.01, respectively). The frequencies of these platelet-related antibodies were comparable between SLE patients with thrombocytopenia and patients with idiopathic thrombocytopenia. Twenty-nine (91%) SLE patients with thrombocytopenia had either anti-GPIIb/IIIa or anti-TPOR antibody, and six had both. In SLE patients with thrombocytopenia, the anti-TPOR-positive patients had significantly higher frequencies of megakaryocytic hypoplasia and poorer therapeutic responses to corticosteroids and intravenous immunoglobulin than did the anti-TPOR-negative patients, most of whom had the anti-GPIIb/IIIa antibody alone.

CONCLUSIONS:

Anti-GPIIb/IIIa and anti-TPOR antibodies are major factors contributing to SLE-associated thrombocytopenia, but the clinical presentations associated with these autoantibodies are different.

• Authors: M Kuwana, J Kaburaki, Y Okazaki, H Miyazaki, Y Ikeda
• Journal: Rheumatology (Oxford, England) (Rheumatology (Oxford)) Vol. 45 Issue 7 Pg. 851-4 (Jul 2006) ISSN: 1462-0324 [Print] England
• PMID: 16418192 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Autoantibodies
• Glucocorticoids
• Immunoglobulins, Intravenous
• Platelet Glycoprotein GPIIb-IIIa Complex
• Proto-Oncogene Proteins
• Receptors, Cytokine
• Receptors, Thrombopoietin
• MPL protein, human

Topics

• Adult
• Autoantibodies (blood)
• B-Lymphocytes (immunology)
• Female
• Glucocorticoids (therapeutic use)
• Humans
• Immunoglobulins, Intravenous (therapeutic use)
• Lupus Erythematosus, Systemic (complications, immunology, therapy)
• Male
• Megakaryocytes (pathology)
• Middle Aged
• Platelet Glycoprotein GPIIb-IIIa Complex (immunology)
• Proto-Oncogene Proteins (immunology)
• Receptors, Cytokine (immunology)
• Receptors, Thrombopoietin
• Thrombocytopenia (etiology, immunology, pathology)
• Treatment Failure