Aberrant expression of HLA-G antigen in interferon gamma-stimulated acute myelogenous leukaemia

We have analysed the expression of HLA-G in 40 leukaemia samples of various subtypes [seven cases of acute lymphoblastic leukaemia (ALL), 28 cases of acute myelogenous leukaemia (AML), three cases of chronic myelogenous leukaemia (CML) and two cases of chronic lymphocytic leukaemia (CLL)] by flow cytometry using HLA-G-specific monoclonal antibody. No leukaemia samples expressed HLA-G without incubation with interferon (IFN)-gamma. However, six out of 28 (21%) AML samples expressed HLA-G upon incubation with IFN-gamma. These six samples derived from one out of seven M2, two out of eight M4 and three out of five M5. The results indicated that AML cells, especially myelomonocytic leukaemia samples, are capable of expressing the HLA-G molecule.