International Journal of Cell Cloning, Vol 4, 447-463, Copyright © 1986 by AlphaMed Press
Complement-dependent cytotoxic factor to megakaryocyte progenitors in sera from patients with idiopathic thrombocytopenic purpura
Y Usuki, M Kohsaki, K Nagai, Y Ohe and H Hara
The influence of sera from patients with idiopathic thrombocytopenic
purpura (ITP) was examined on colony formation from megakaryocyte (M)
progenitors. Though incubation of marrow cells in Iscove's modified
Dulbecco's medium (IMDM) containing 50% sera from several ITP patients
stimulated M-colony formation in 8 of 13 cases, incubation in the sera from
the patients and in baby rabbit serum as a source of complement
significantly suppressed the colony formation. Experiments showed that sera
of immunoglobulin G from ITP patients had significant complement- dependent
cytotoxicity to M-progenitors in normal marrow cells or in the marrow cells
from corresponding patients, but not to CFU-e, BFU-e or CFU-gm. Cytospin
preparations of individually collected M-colonies from marrow cells treated
with ITP patients' sera and complement revealed a reduction of
megakaryocyte colonies containing cells of multilineages. These results
indicate that autoantibodies detected in ITP patients can bind not only to
platelets and megakaryocytes, but may also bind to M-progenitors.
