[Analysis of CD34+ cell amounts in normal and abnormal bone marrow cells of patients with paroxysmal nocturnal hemoglobinuria].
OBJECTIVE
To explore the contributive role of CD34+ cell amount in pathogenesis of clonal dominance in paroxysmal nocturnal hemoglobinuria (PNH).


METHODS
Bone marrow nuclear cells (BMNCs) were doubly labeled by PE-conjugated anti-CD59 monoclonal antibody (McAb) and FITC-conjugated anti-CD34 McAb, and CD34+ cells contained in different cell populations were determined by flow cytometry.


RESULTS
1. CD34+ cells mainly appeared in window A (containing mainly of lymphocytes) and window D (composed of blasts, other immature cells and monocytes) in both normal controls and PNH patients. 2. The numbers of CD34+ cells in normal controls were (3,701 +/- 896)/10(5) cells and (11,373 +/- 1,574)/10(5) cells in window A and window D, respectively. Compared with normal controls, PNH patients possessed significantly decreased number of CD34+ cells [(1,215 +/- 749)/10(5) cells and (6,420 +/- 2,337)/10(5) cells in window A and window D, respectively]. 3. In normal controls, nearly all CD34+ cells in windows A and D expressed CD59 antigen (99.2% +/- 1.0% in A and 98.7% +/- 0.8% in D), whereas in PNH patients, the CD34+ cells clearly showed two immunophenotypes of CD34+CD59+ and CD34+CD59- with the latter being predominant in both window A and window D(CD59- cells constituting 79.3% +/- 15.5% and 85.9% +/- 7.8% of CD34+ cells, respectively). 4. The amounts of CD34+ cells in CD59+ populations [(463 +/- 276)/10(5) cells in window A and (3,841 +/- 1,188)/10(5) cells in window D] reduced to a greater extent than that in CD59- population [(2,603 +/- 2,084)/10(5) cells in window A and (7,105 +/- 2,739)/10(5) cells in window D].


CONCLUSIONS
Hematopoietic stem/progenitor cells in BMNCs of PNH patients are markedly decreased. Reduction of CD34+ cells in CD59+ cell population is even more obvious than that in CD59- population. The dominance of the abnormal clone in hematopoiesis might be a relative one in the setting of severely impaired normal hematopoiesis.
Li
Q
Q
Department of Hematology, Peking Union Medical College Hospital, CAMS and PUMC, Beijing 100730.
Zhang
Z
Z
Liu
E
E
D018952:Antigens, CD34 / Q000032:analysis*; D001854:Bone Marrow Cells / Q000276:immunology / Q000473:pathology*; D018957:CD59 Antigens / Q000032:analysis*; D006410:Hematopoiesis; D006412:Hematopoietic Stem Cells / Q000473:pathology*; D006457:Hemoglobinuria, Paroxysmal / Q000276:immunology / Q000473:pathology*; D006801:Humans
D018952:Antigens, CD34; D018957:CD59 Antigens