THE EXPRESSION
OF IMMUNOPROTEASOME SUBUNITS�� AND PRO-TEASOME
ACTIVATORS AND THEIRS RELATION TO LINICAL AND BIOLOGICAL CHARACTERISTICS IN
CHILDHOOD ACUTE LEUKEMIA
Xie J-J1, Hu Y-M1,
Lu Y-Y2, Li W-M2, Gong W-Y1, Li J1
1 Beijing Children's Hospital, Beijing,
China
2 Clinical College of Tumor, Beijing
University, Beijing, China
Objective: To 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 50 inpatients with
childhood AL were collected. And then mononuclear cells were separated. (2)
Western Blotting was performed for the detection of LMP2(low-molecular mass
polypeptide), LMP7, TAP1(transporter1 associated with antigen processing),
PA28�� and PA28��(proteasome activator) expression.
Results: (1) The ratios of intensively positive, weakly
positive and negative expression of LMP7 in AL were 23.3%, 38.9% and 44.4%
respectively, and were significantly different from those in control
(p<0.05). d Negative expression of LMP7 was seen in 70% of inpatients
with relapsed AL, which was significantly different from that in 18.8% of
inpatients with de novo AL;
(2)The expression of LMP2, TAP1, PA28��and
PA28��in AL were not
significantly different from those in control (p>0.05); (3)The decrease
or loss of LMP7 expression was related to relapse (p<0.05).,and the
expressions of LMP2, PA28��, PA28�� and TAP1 were not related
to clinical and biological characteristics (p>0.05).
Conclusion: (1) Decreased generation of endogenous antigen
pepetide resulting from LMP7 deficiency exits in
leukemic cell, which will possibly be related to the escape of leukemic
cells from immune surveillance in childhood AL. (2) Decrease or loss of
LMP7 expression is possibly related to relapsed leukemia.