Effect of conditioned media of acute myeloid leukemia blast cells on complement synthesis by cultured human cells of monocyte and hepatocyte origin.
The effect of conditioned media of 3-day cultures of blast cells from peripheral blood of 5 patients with acute myeloid leukemia (CM-AML) was studied on the synthesis of C2, factor B (Bf) and C1 esterase inhibitor (C1-INH) by human monocyte-macrophage cultures and HepG2 hepatoma cell line. The level of C2 in the culture supernatants was measured by immune hemolysis, those of Bf and C1-INH by ELISA. CM-AML was added to the monocyte cultures on day 3 and replaced by culture fluid on day 6. Compared to the control cultures, CM-AML significantly increased C2 and Bf levels and slightly decreased C1-INH levels in the culture fluids on day 6. On day 9, Bf synthesis enhancement still could be observed but C2 and C1-INH levels did not significantly differ from those of the control. CM-AML significantly increased the synthesis of factor B by the HepG2 cells too. A strong correlation was found between the results of the Bf protein and RNA determinations, which means that the supernatants of AML blasts affect the gene expression of factor B at a pretranslational level. The selective complement synthesis modifying effect of CM-AML was not due to interferons (IFN) because neither IFN-alpha nor IFN-gamma could be detected in these conditioned media. The present findings indicate that the hypercomplementemia observed in AML patients can be due to unknown factor(s) produced by leukemic blast cells.
Gyapay
G
G
National Institute of Hematology and Blood Transfusion, Budapest, Hungary.
Schmidt
B
B
Válay
M
M
Falus
A
A
Anh-Tuan
N
N
Pánya
A
A
Kókai
M
M
Onody
K
K
Mód
A
A
Füst
G
G
D001773:Blood Cells / Q000276:immunology*; D015152:Blotting, Northern; D002478:Cells, Cultured; D003175:Complement C2 / Q000096:biosynthesis; D011415:Complement Factor B / Q000096:biosynthesis; D003165:Complement System Proteins / Q000096:biosynthesis*; D003470:Culture Media / Q000494:pharmacology; D004306:Dose-Response Relationship, Immunologic; D006801:Humans; D066298:In Vitro Techniques; D016898:Interferon-alpha / Q000032:analysis; D007371:Interferon-gamma / Q000032:analysis; D007951:Leukemia, Myeloid / Q000276:immunology*; D008099:Liver / Q000378:metabolism*; D008264:Macrophages / Q000378:metabolism; D009000:Monocytes / Q000378:metabolism*
D003175:Complement C2; D003470:Culture Media; D016898:Interferon-alpha; D007371:Interferon-gamma; D003165:Complement System Proteins; D011415:Complement Factor B