THE EXPRESSION OF IMMUNOPROTEASOME
SUBUNITS¦ÂAND TAP AND THEIRS RELATION TO CLINICAL AND
BIOLOGICAL CHARAC-TERISTICS IN CHILDHOOD ACUTE LEUKEMIA
Xie
J-J1, Hu Y-M1, Lu Y-Y2, Li W-M2,
LI Z-G2, Gong W-Y1
1 Beijing
Children's Hospital, Beijing, China
2 Clinical
College of Tumor, Beijing University, Beijing, China
Objective: To further investigate whether the function of
antigen processing and presentation is deficient and related to clinical
and biological characteristics in childhood acute leukemia (AL).
Methods: (1) The clinical and biological data and
anti-coagulated bone marrow from 23 inpatients with childhood AL were
collected. Mononuclear cells were separated from bone marrow. (2) Reverse
transcription-polymerase chain reaction (RT-PCR) analysis was performed for
the detection of LMP2(low-molecular mass polypeptide), LMP7, LMP10, TAP1
and TAP2 mRNA expression .
Results: (1) The ratios of "++","+" and
"-" for LMP7 expression were 17.4%, 34.8% and 47.8% respectively
in AL,and the corresponding values for LMP10 expression were 39.1%, 8.7%
and 52.1% respectively, and were significantly different from those of
control (p<0.05); (2) The decrease or loss of LMP7 mRNA expression was
related to relapsed leukemia (p<0.05). (3) The decrease or loss of LMP10
mRNA expression was related to abnormal cytogenetics (p<0.05). The level
of LMP2 expression was not related to clinical and biological
characteristics in childhood AL. (3) The expression of TAP2 mRNA was
significantly different in AL from control (p<0.05).
Conclusion:
The defect of processing and presentation associated with endogenous
antigen pepetide exists in leukemic cells in childhood AL, resulting in the escape of leukemic cells from immune surveillance
in childhood AL. (3) Decrease or loss of LMP7 expression is possibly
related to relapsed childhood AL, and decrease or loss of LMP10 expression
is possibly related to abnormal cytogenetics in childhood AL.