Blood, 1966, Vol. 28, No. 6, pp. 807-829.
© 1966 American Society of Hematology, Inc.
Classification and Evolution of Patterns of Erythropoiesis
in Polycythemia Vera as Studied by Iron Kinetics
M. POLLYCOVE 1,
H. S. WINCHELL 1,
J. H. LAWRENCE 1, and
N. Kusubov 1
1 Donner Laboratory, University of California, Berkeley, California.
1. Patients with polycythemia vera may be classified according to their
erythropoietic pattern. Erythropoiesis is abnormally increased in all classes.
Class I is characterized by normal red cell lifespan. Class II is characterized by
shortened red cell lifespan; in Class IIa the shortened red cell survival is related
to splenic sequestration of RBC; in Class IIb the markedly shortened red cell
survival is predominantly related to intramedullary hemolysis. Class III is
characterized by extramedullary erythropoiesis. Patients in Classes I and IIa
are in relatively earlier phases of their disease and frequently are found to
develop red cell kinetics of Class III as their disease progresses. Conversely,
patients in Classes IIb and III are generally late in the course of their disease
and have previous hematologic findings that suggest that they originally had
the red cell kinetic patterns of Classes I and IIa.
2. As the duration of their disease increases, patients with polycythemia vera
generally have a progressive shortening of red cell lifespan which is incompletely compensated by a progressive decrease in circulating red cell volume.
However, total blood volume remains elevated since the plasma volume increases. These changes occur whether or not the patient receives radiation
therapy. Similar changes may occur in white cell and platelet production and
functional survival. It is suggested that the natural history of the disease may
be characterized by progressive emergence of hematopoietic cell clones which
have a selective advantage for reproduction associated with altered functional
survival.
3. The results suggest the potential usefulness of iron, and occasionally of
splenectomy, in selected polycythemic patients with myeloid metaplasia (Class
III) and anemia, dependent upon the presence of the frequent finding of iron
deficiency or the occasional finding of splenic sequestration of red cells in
excess of splenic erythropoiesis.
Submitted on September 30, 1965
Accepted on March 6, 1966
