[The immunophenotypic analysis of CD7+ and (or) CD56+ acute myeloid leukemic stem cells and its applications in minimal residual disease detection].
OBJECTIVE
To explore the immunophenotypic characteristics of CD7 and/or CD56 positive acute myeloid leukemic stem cells, and the relationship between minimal residual disease (MRD) and the leukemic stem cells (LSC).


METHODS
The immunophenotype of leukemia cells from 51 CD34+ CD38+ CD7+ and/or CD34+ CD38+ CD56+ acute myeloid leukemia (AML) patients (exclude M3) at diagnosis was analyzed by using 4 - 6 panels of 4 color antibodies, and cells from 28 normal bone marrow (NBM) samples were served as control. The expression of CD7 and CD56 in the CD34+ CD38+ subpopulation was used as a leukemic cell marker for monitoring MRD of 53 samples from 26 CD7+ and (or) CD56+ patients.


RESULTS
In CD7+ and/or CD56+ AML patients at diagnosis, the average positivity of CD7 in CD34+ CD38+ subpopulation and CD34+ CD38- Lin- stem cells subpopulation was (77.39 +/- 20.71)% and (44.57 +/- 22.70)%, and that of CD56 was (56.71 +/- 32.56)% and (33.51 +/- 29.64)%, respectively, all significantly higher than that of NBM (P < 0.01 and P < 0.05). Compared with that of NBM, the expression of CD90 in AML patients was significantly lower in the CD34+ CD38- Lin- subpopulation (P < 0.01), the expression of CD123 was significantly higher than NBM (P < 0.01), and the expression of CD117 was no significant difference (P > 0.05). In follow up of CD7+ and (or) CD56+ patients, the expression rate of CD7 and (or) CD56 in the CD34+ CD38- Lin- subpopulation MRD+ group was significantly higher than that in the MRD- group. The actual rate for CD7 was 71% (15/21) and 16% (4/25) (P = 0.001), and its relative rate was 81% (17/ 21) and 24% (6/25) (P = 0.000), respectively. The actual rate of CD56 is 100% (4/4) and 12% (3/25) (P = 0.001), and its relative rate was 75% (3/4) and 20% (5/25) (P = 0.031), respectively. A high CD7+ CD34+ CD38- Lin- subpopulation frequency at diagnosis in CD7+ AML patients predicted a high frequency of positive MRD in later detection (P < 0.05).


CONCLUSIONS
CD7 and CD56 are expressed on the stem cells in CD7+ and/or CD56+ AMLs and a high frequency of CD7 and CD56 in the CD34+ CD38- Lin- stem cell subpopulation predicts a high frequency of positive MRD in later detection.
Cao
Hui
H
People's Hospital of Peking University, Beijing 100044, China.
Wang
Ya-Zhe
YZ
Wu
Hong-Hong
HH
Chang
Yan
Y
Hao
Le
L
Chen
Shan-Shan
SS
Huang
Xiao-Jun
XJ
Lu
Dao-Pei
DP
Liu
Yan-Rong
YR
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019011:Antigens, CD7 / Q000235:genetics; D019002:CD56 Antigen / Q000235:genetics; D002648:Child; D002675:Child, Preschool; D005260:Female; D005500:Follow-Up Studies; D006412:Hematopoietic Stem Cells / Q000276:immunology; D006801:Humans; D016130:Immunophenotyping; D015470:Leukemia, Myeloid, Acute / Q000175:diagnosis / Q000235:genetics / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D018365:Neoplasm, Residual / Q000175:diagnosis* / Q000235:genetics / Q000276:immunology; D014411:Neoplastic Stem Cells / Q000276:immunology*; D055815:Young Adult
D019011:Antigens, CD7; D019002:CD56 Antigen