Cyclic thrombocytopenia of apparent autoimmune etiology
JE Menitove, J Pereira, R Hoffman, T Anderson, W Fried and RH Aster
Blood Center of Southeastern Wisconsin, Milwaukee 53233.
Serial studies were performed in two patients with cyclic thrombocytopenia
to investigate the pathogenesis of this disorder. Mean life span of
autologous platelets when platelet levels were declining was subnormal (2.4
and 0.8 days), and megakaryocytes were abundant in the bone marrow during
thrombocytopenia. Megakaryocyte colony- stimulating activity could not be
detected in the serum of either patient at any point of their cycles. In
each patient, total platelet- associated IgG varied inversely with platelet
levels. Surface platelet- associated IgG was measured only in patient 2 and
was significantly elevated (greater than 1,280 IgG molecules per platelet)
at all stages of the cycle, even during thrombocytosis. However, the
highest values were observed during thrombocytopenia. Platelet-bindable IgG
in plasma declined to normal immediately before platelet levels began to
rise. IgG eluted from the platelets of this patient reacted strongly with
autologous and homologous platelets in contrast to a "mock eluate" prepared
from platelets of a normal subject. The eluate from the patient's platelets
reacted strongly with immobilized autologous and homologous glycoprotein
IIb/IIIa complex and weakly with GPIb but not with isolated GPIIIa alone.
In each patient the decline in platelet levels was significantly delayed
following administration of intravenous gamma globulin 0.4 g/kg body weight
for five days. These findings suggest that platelet-reactive autoantibodies
are of pathogenic significance in some patients with cyclic
thrombocytopenia.
Volume 73,
Issue 6,
pp. 1561-1569,
05/01/1989
Copyright © 1989 by The American Society of Hematology
