Antivinculin antibodies in sera of patients with immune thrombocytopenia
and in sera of normal subjects
Y Tomiyama, R Kekomaki, J McFarland and TJ Kunicki
Blood Center of Southeastern Wisconsin, Milwaukee 53233.
We have characterized a 120-Kd antigen that frequently reacts with serum
antibodies from patients with immune thrombocytopenia or normal subjects.
Immunoblots made after two-dimensional nonreduced/reduced sodium dodecyl
sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) or two-dimensional
isoelectric focusing/SDS-PAGE demonstrated that this 120-Kd protein has the
same molecular weight under nonreduced or reduced conditions, is not a
surface protein, and has an isoelectric point (pl) of 6.4 to 6.5. From
these data, one likely candidate is the intracellular platelet protein,
vinculin. Monoclonal antivinculin antibody reacts with this 120-Kd protein,
and purified human platelet vinculin is bound by antibodies that recognize
the 120-Kd protein. Therefore, we conclude that this 120-Kd protein is
identical to vinculin. Data obtained from a sensitive enzyme-linked
immunosorbent assay demonstrate the presence of naturally occurring
antivinculin antibodies in many normal sera. However, the incidence of
antivinculin antibodies in patient sera (67%; 55 of 82 sera) is
significantly (P less than .01) higher than that in normal sera (40%; 32 of
80 sera), and there is a significant difference (P less than .05) between
the mean levels of antivinculin antibodies in patient and normal sera.
Whereas the levels of these antibodies in patient and normal sera overlap,
2 of 82 sera from patients with thrombocytopenia express unusually high
levels of such antibodies. The pathologic significance of these antibodies
remains to be determined.
Volume 79,
Issue 1,
pp. 161-168,
01/01/1992
Copyright © 1992 by The American Society of Hematology
