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Bcl‐2 and Bcl‐x expression in the CD34 + cells of aplastic anaemia patients: relationship with increased apoptosis and upregulation of Fas antigen
Author(s) -
Ismail M.,
Gibson F. M.,
GordonSmith E. C.,
Rutherford T. R.
Publication year - 2001
Publication title -
british journal of haematology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.907
H-Index - 186
eISSN - 1365-2141
pISSN - 0007-1048
DOI - 10.1046/j.1365-2141.2001.02810.x
Subject(s) - cd34 , apoptosis , antigen , biology , haematopoiesis , downregulation and upregulation , microbiology and biotechnology , cancer research , stem cell , cytotoxic t cell , immunology , in vitro , biochemistry , gene
Aplastic anaemia (AA) is a syndrome of haemopoietic failure involving increased apoptosis in stem cells. AA CD34 + cells often have upregulated Fas antigen, but this does not explain the increased apoptosis in all patients. To examine whether abnormal expression of the apoptotic modulators Bcl‐2 and Bcl‐x is involved in increased apoptosis in the CD34 + cells of patients, we examined cells from 19 AA patients and 18 normal controls by triple staining for CD34, Bcl‐2 or Bcl‐x, together with 7‐amino actinomycin D to determine viability or with staining for Fas antigen. We confirmed increased apoptosis of CD34 + cells in patients. All CD34 + cells in patients and controls expressed Bcl‐2 and Bcl‐x with no significant difference between the groups. In patients, viability of CD34 + /Bcl‐2 hi cells was similar to that of CD34 + /Bcl‐2 lo cells, but CD34 + /Bcl‐x hi cells were significantly more viable than CD34 + /Bcl‐x lo cells. CD34 + cells from AA patients expressed upregulated Fas antigen, but this did not correlate with Bcl‐2 or Bcl‐x expression. These results suggest a more significant role for Bcl‐x as an anti‐apoptotic regulator in CD34 + cells in AA than Bcl‐2. The induction of death by Fas antigen may bypass the anti‐apoptotic effect of Bcl‐2 and Bcl‐x in CD34 + cells in AA.