Erythroid progenitors in adult chronic pure red cell aplasia: relationship
of in vitro erythroid colonies to therapeutic response
C Lacombe, N Casadevall, O Muller and B Varet
Twenty-two cases of idiopathic chronic pure red cell aplasia (PRCA) in
adults have been studied to evaluate their erythroid progenitors in vitro
using the plasma clot technique. Three types of culture growth patterns
were observed and classified as follows. Type I: showing a normal number of
autologous CFU-E; type II: CFU-E and BFU-E were detectable but constantly
decreased; type III: CFU-E and BFU-E were undetectable. The results were
reproducible when patients were studied on two or more occasions. A strong
correlation was found between the in vitro growth of autologous erythroid
colonies and the results of immunomodulating therapy in 18 evaluable
patients. A constant response to immunomodulating treatment was observed in
type I patients. A constant failure of treatment was observed in type III
patients, whereas results of therapy were unpredictable in type II
patients. Two patients with chronic PRCA associated with thymoma and three
with chronic myeloproliferative disorders were also studied. Patients with
PRCA and thymoma behaved in vitro like type I patients. Patients with
chronic myeloproliferative disorders exhibited very low numbers or no CFU-E
or BFU-E (type II or III). These data support the hypothesis that at least
two mechanisms are responsible for PRCA--one immunologically mediated and
the other resulting from a stem cell defect. Moreover, they suggest that
the study of erythroid progenitors in vitro might be useful in predicting
the immunosuppressive therapy effect in adult chronic PRCA.
Volume 64,
Issue 1,
pp. 71-77,
07/01/1984
Copyright © 1984 by The American Society of Hematology
