Abstract
Treatment of acute myeloid leukaemia (AML) cells with
differentiation agents leads not only to the acquisition of normal
phenotypes but also contributes to the understanding of special
immuno-haematology issues. For instance, induction of HLA-DR
antigens on human promyelocytic leukaemia HL-60 cells by
interleukin-4 (IL-4) is of pivotal importance in immunology not
only because class II expression is prerequisite to antigen
recognition and response but also because IL-4 participates in a
plethora of inflammatory or non-inflammatory reactions. At the same
time, the same observation coupled with an increase in Mac-1, mature
monocyte marker, is revealing ways to haematologists for converting
malignant cases to normal situations. Based on previous reports that
HLA-DR induction by IL-4 in the HL-60 system is mediated via the
G-protein system (