Application of series of monoclonal antibodies against human white cell differentiation antigens and the common ALL antigen in the characterization of leukemia cells.

The specificity and the clinical usefulness of the hybridoma derived monoclonal antibodies raised against the differentiation antigens of granulocytes (VIM-D5, VIM-C6), monocytes (VIM-D2), B lymphocytes (VIB-C5, VIC-Y1), erythrocytes (VIE-G4) and CALLA (VIL-A1) was studied in leukemic cells isolated from peripheral blood and bone marrow of 41 adults with acute leukemia by using indirect fluorescence method. The VIL-A1 positivity was observed in 4/9 of ALL and in none of myeloid leukemia. It was accompanied in 3/4 of cases by VIB-C5 positivity and in one case by VIE-G4 positivity. It is important that 2 out 3 unclassifiable cases (PAS-) could be diagnosed as common ALL due to their VIL-A1 positivity. VIM-D5 like VIM-C6 reacted specifially with granulocytic cells only and gave positive results in 20/30 of acute myeloid leukemias. When classified according to the FAB scheme, the proportion of VIM-D5 + patients rose from M1 toward more mature subtypes, including M4/5. It allowed to identify as AML 2/6 of unclassifiable-Mo leukemias, VIC-Y1 appeared to be helpful in characterization of B cell malignancies and of myelomonocytic leukemias. It is concluded that the monoclonal antibodies of VI series are specific and allow a more precise definition of leukemia, thus helping in optimalization of treatment.