Antiplatelet antibody testing in thrombocytopenic pregnant women.
OBJECTIVE
The purpose of the study was to attempt to distinguish pregnant women with gestational thrombocytopenia from those with idiopathic immune thrombocytopenia by eight different platelet antibody assays.


METHODS
Sera from pregnant women with presumed gestational thrombocytopenia (n = 160) and idiopathic immune thrombocytopenia (n=90) were prospectively tested for indirect and platelet-associated immunoglobulins G and M and complement C3, as well as for serotonin release. After the results were analyzed, a subset of patients were subsequently analyzed for circulating antiplatelet antibody directed against platelet membrane glycoprotein GPIIb/IIIa.


RESULTS
Indirect immunoglobulin G was significantly greater in the 85 women with idiopathic immune thrombocytopenia than in the 129 women with gestational thrombocytopenia (p<0.001). Platelet-associated immunoglobulin G was elevated in the majority of women, both those with gestational thrombocytopenia and those with idiopathic immune thrombocytopenia. There were also no statistically significant difference in the values for platelet-associated C3 or indirect immunoglobulin M and C3. Levels of platelet-associated immunoglobulin M showed a tendency to be higher in women with gestational thrombocytopenia (p=0.04), as did the values in the serotonin release assay (p=0.06).


CONCLUSIONS
Our data demonstrate that patients with gestational thrombocytopenia had surprisingly high levels of platelet-associated immunoglobulin despite mild thrombocytopenia. Comparison of a relatively large number of patients with idiopathic immune thrombocytopenia and gestational thrombocytopenia indicates that women with idiopathic immune thrombocytopenia cannot be distinguished from those with gestational thrombocytopenia by means of one or more of the prototypic platelet antiglobulin tests currently in use. Our preliminary data with glycoprotein-specific assays indicate that they may be more useful.
Lescale
K B
KB
Department of Obstetrics and Gynecology, New York Hospital-Cornell Medical Center, New York, NY 10021, USA.
Eddleman
K A
KA
Cines
D B
DB
Samuels
P
P
Lesser
M L
ML
McFarland
J G
JG
Bussel
J B
JB
D001323:Autoantibodies / Q000097:blood*; D001792:Blood Platelets / Q000276:immunology*; D003176:Complement C3 / Q000378:metabolism; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D007075:Immunoglobulin M / Q000097:blood; D016014:Linear Models; D019039:Platelet Glycoprotein GPIIb-IIIa Complex / Q000276:immunology; D011247:Pregnancy; D011250:Pregnancy Complications, Hematologic / Q000175:diagnosis / Q000276:immunology*; D011446:Prospective Studies; D016553:Purpura, Thrombocytopenic, Idiopathic / Q000175:diagnosis / Q000276:immunology; D013921:Thrombocytopenia / Q000175:diagnosis / Q000276:immunology*
D001323:Autoantibodies; D003176:Complement C3; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D019039:Platelet Glycoprotein GPIIb-IIIa Complex