[Participation of bonth splenic CD(5)(+) and CD(5)(-) B lymphocytes in production of platelet glycoprotein-specific autoantibodies in chronic ITP].
OBJECTIVE
To investigate the percentage of splenic CD(5)(+) B lymphocytes in chronic idiopathic thrombocytopenic purpura (IT) and the impact of splenic CD(5)(+) and CD(5)(-) B lymphocytes on the production of platelet glycoprotein (GP)-specific autoantibodies.


METHODS
Splenic CD(5)(+) B lymphocytes were identified by two-color flow cytometric analysis in eight patients. Four of the eight patients displayed plasma autoantibodies against both GPIIb/IIIa and GPIb/IX, and their splenic B lymphocytes were separated by Ficoll-Hypaque density gradient and sheep erythrocyte, and further purified by magnetic activate cell separation (MACS). Purified CD(5)(+) and CD(5)(-) B lymphocytes were cultured separately with or without staphylococcus aureus cowan I (SAC). GP specific autoantibodies in culture supernatants were measured by modified monoclonal antibody immobilization of platelet antigen assay (MAIPA).


RESULTS
The percentage of splenic CD(5)(+) B lymphocytes in ITP patients was slightly higher than that in control with no statistical significance. MACS purified splenic CD(5)(+) and CD(5)(-) B lymphocytes from three out of four ITP patients produced high levels of anti-GPIIb/IIIa and anti-GPIb/IX antibodies. Culture supernatants of CD(5)(+) B lymphocytes from the other patient showed positive reaction only in GPIb/IX MAIPA. Culture supernatant of CD(5)(-)B lymphocytes from the same patient were double positive in both GPIIb/IIIa and GPIb/IX MAIPA.


CONCLUSIONS
Both splenic CD(5)(+) and CD(5)(-) B lymphocytes produce platelet GP-specific autoantibodies in chronic ITP with similar antibody spectrum and titer, and may all play a role in the autoimmune pathogenesis of ITP.
Lu
Baojun
B
Department of Haematology, Qilu Hospital of Shandong University, Jinan 250012, China.
Hou
Ming
M
Lu
Lu
L
Shi
Yan
Y
He
Qingsi
Q
Ma
Daoxin
D
Zhang
Maohong
M
D000293:Adolescent; D000328:Adult; D001323:Autoantibodies / Q000096:biosynthesis*; D001402:B-Lymphocytes / Q000276:immunology*; D018956:CD5 Antigens / Q000032:analysis*; D002908:Chronic Disease; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D019039:Platelet Glycoprotein GPIIb-IIIa Complex / Q000276:immunology*; D019038:Platelet Glycoprotein GPIb-IX Complex / Q000276:immunology*; D016553:Purpura, Thrombocytopenic, Idiopathic / Q000276:immunology*; D013154:Spleen / Q000166:cytology
D001323:Autoantibodies; D018956:CD5 Antigens; D019039:Platelet Glycoprotein GPIIb-IIIa Complex; D019038:Platelet Glycoprotein GPIb-IX Complex