Leu-10 (HLA-DC/DS) antigen distribution in human leukaemic disorders as detected by a monoclonal antibody: correlation with HLA-DR expression.

Reactivity of the monoclonal antibody anti-Leu-10 that detects the human equivalent of the murine 1-A subregion antigen(s) was studied and correlated with anti-HLA-DR expression on 83 cases of acute and chronic leukaemias, leukaemic non-Hodgkin's lymphomas (NHL) and seven human cell lines. Peripheral blood and/or bone marrow leukaemic cell suspensions were stained by indirect immunofluorescence for both monoclonal antibodies and analysed by flow cytometry. Leu-10, like HLA-DR, was absent from T-cell acute lymphoblastic leukaemia (ALL) (two cases). It was expressed on: 33% of TdT +, CALLA + ALL cases (8/24); 27% (4/15) of acute non-lymphocytic leukaemia (ANLL); 85% (24/28) of HLA-DR + B-cell chronic lymphocytic leukaemia (CLL); and on 9/14 (64%) B-cell NHL cases. There were no differences in clinical characteristics between Leu-10 + and Leu-10--patient subgroups. We were able to induce Leu-10 expression on 'Josh' cell line by culturing it with 12-0-tetra-decanoylphorbol-13-acetate (TPA). Our data indicate that Leu-10 expression on leukaemic cells is more restricted than HLA-DR and is likely to be differentiation related, since it can be induced to be expressed at a later stage than HLA-DR.