[Leukemic dendritic cells in patients with acute myeloid leukemia]

To determine surface and intracellular expression of ACE antigen and Bip shaperon on leukemic dendritic cells (LDC); to study expression of ACE genes and Bip, Calnexin, calreticulin shaperons in LDC at diagnosis of acute myeloid leukemia (AML) under standard and stress cultivation.

Expression of ACE antigens and Bip was studied with immunophenotyping and flow cytometry using monoclonal antibodies to shaperon Bip and to CD143), expression of genes of ACE and shaperons Bip, Calnexin, Calreticulin--with polymerase chain reaction (RT-PCR). Dendritic cells (DC) were obtained by culturing of a monoclonal fraction of donor peripheral blood and AML patients in the presence of 180 ng/ml calcium ionophor A23187 (Sigma) for 4 days in parallel at 37 degrees C and 33 degrees C in the atmosphere of 5% CO2. The trial included 9 patients (5 males and 4 females) aged 39-53 years (median 43 years). The control group consisted of 8 healthy donors.

Lowering of cultivation temperature did not increase ACE expression. Intracellular shaperon Bip rose insignificantly (1.3-fold) in DC of the controls. ACE and Bip shaperon expression on LDC membrane increased 15- and 11-fold, respectively, while the level of intracellular ACE and Bip decreased 11- and 2-fold, respectively. Expression of the genes was investigated in cultivation temperature lowering from 37 to 33 degrees C and was presented as a logarithmic scale. Changes in expression of the genes Bip, Calnexin, Calreticulin in LDc and DC of the controls were insignificant. ACE expression in LDC significantly differed from ACE gene expression in DC (p = 0.05).

LCD and DC of healthy donors are cells which differ by genetic and functional characteristics. Therefore, LDC may response inadequately in development of antitumor immune response. The phenomenon of ACE antigen expression normalization on cell membrane in stress open new opportunities for regulating functional activity of LDC.