Endogenous erythroid colony assay in patients with polycythemia vera and its clinical significance.
BACKGROUND
Polycythemia vera (PV) is a malignant disorder of hemaopoietic stem cells which is characterized by clonal hyperproliferation and a low rate of apoptosis. This study was to assess endogenous erythroid colony (EEC) formation in the bone marrow of PV patients and determine its clinical significance.


METHODS
The bone marrow mononuclear cells of 26 patients with PV, 2 patients with secondary erythrocytosis (SE), and 19 normal controls were cultured by Marsh's method for EEC evaluation, and the clinical significance was evaluated.


RESULTS
EECs appeared in 25 patients with PV but not in 2 patients with SE and 19 normal controls. The number of EECs and the EEC ratio [EEC/erythropoietin (EPO)-dependent colony forming unit-erythroid (CFU-E)] in PV patients positively correlated with hemoglobin (Hb) levels. Their EEC number did not correlate with white blood cell (WBC) counts, platelet (PLT) counts, or leukocyte alkaline phosphatase (LAP) scores. Their EEC did not correlate with serum EPO levels. Fifteen patients with PV were treated with hydroxyurea (Hu) and/or interferon-alpha (IFN-alpha). Their EEC ratio before treatment positively correlated with the treatment time required for complete remission (CR) and negatively correlated with the time before relapse. The EEC numbers of 7 PV patients treated with Hu/IFN-alpha decreased after the blood cell counts dropped to normal levels. There was a positive correlation between the EEC ratio and the incidence of attacks of vascular thrombosis in PV patients. The numbers of apoptosised bone marrow mononuclear cells in PV patients were lower than those in normal controls. The EEC numbers of PV patients negatively correlated with the rate of apoptosis of bone marrow mononuclear cells.


CONCLUSIONS
EEC formation is characteristic in PV patients. EEC number in PV patients positively correlates with Hb levels, the time required for CR, and the incidence of attacks of vascular thrombosis. EEC number negatively correlates with the time before relapse. Bone marrow suppressive treatment might decrease EEC number. Thus, EEC number is a sensitive and specific parameter reflecting the abnormal hematopoietic clone burden induced by polycythemia vera. EEC number is an important diagnostic parameter for PV patients.
Bai
Jie
J
Department of Clinical Hematology, Blood Diseases Hospital, Chinese Academy of Medical Sciences, Peking Union Medical College, Tianjin 300020, China.
Shao
Zong-hong
ZH
Liu
Hong
H
Shi
Jun
J
He
Guang-sheng
GS
Cao
Yan-ran
YR
Cui
Zhen-zhu
ZZ
Wu
Yu-hong
YH
Sun
Juan
J
Tian
Zheng
Z
Jia
Hai-rong
HR
Qian
Lin-sheng
LS
Yang
Tian-ying
TY
Yang
Chong-li
CL
D000328:Adult; D000368:Aged; D017209:Apoptosis; D003114:Colony-Forming Units Assay; D015672:Erythroid Precursor Cells / Q000502:physiology*; D004920:Erythropoiesis; D004921:Erythropoietin / Q000097:blood; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011087:Polycythemia Vera / Q000097:blood* / Q000628:therapy; D013927:Thrombosis / Q000453:epidemiology
D004921:Erythropoietin