[Two-color flow cytometric analysis on human peripheral blood T-lymphocytes using monoclonal antibody BM-1 directed to Le(Y) determinant structure].

We developed a new assay method for the evaluation of Le(Y) antigen expression on human peripheral T-lymphocytes using the monoclonal antibodies BM-1, CD4 and CD8 by two-color flow cytometry. Le(Y) antigen expressed on human peripheral T-lymphocytes was stained with fluorescein isothiocyanate (FITC)-labelled BM-1 (anti Le(Y) monoclonal antibody). Le(Y) positive cells were simultaneously stained with phycoerythrin (PE)-labelled CD4 or CD8, then analyzed by flow-cytometer. Coefficients of variations in this double staining assays were 4.2% for BM-1 in CD4 and 5.3% for BM-1 in CD8, respectively. In 124 healthy volunteers 0.2-13.1% of CD4 and 2.5-12.5% of CD8 positive cells were BM-1 positive. Lymphocytes from 200 patients with acute or chronic viral hepatitis showed marked increase in BM-1 expression of CD8 positive cells during the acute phase and exacerbation of the disease. Moreover, BM-1 expression of CD4 cells was positively related with the course of the chronic hepatitis and the prognosis of each patients. Therefore, this new assay using BM-1 and CD4, CD8 monoclonal antibodies would reflect progression of viral hepatitis and its related immunological condition.