Improved flow cytometric method for HLA-B27 typing.

HLA-B27 is a cell marker of clinical interest because of its high association with certain diseases. The HLA-B27 antigen was detected on lymphocytes using a monoclonal antibody in an indirect immuno-fluorescence assay using a fluorescence flow cytometer. The considerable crossreaction of the monoclonal antibody with the HLA-B7 antigen was effectively suppressed by masking it by means of human anti-HLA-B7 antiserum. The flow cytometric method was evaluated by comparing the results with those obtained by the standard lymphocytotoxicity test and showed complete agreement in 107 selected patient samples.