A simplified one-step procedure for the simultaneous determination of complement receptor lymphocytes and lymphocytes with membrane-bound immunoglobulins.

A simple one-step procedure for the demonstration of complement receptor lymphocytes (CRL) with complement-coated bacteria (BC) as indicator particles is described. With this assay the percentage of CRL in normal peripheral blood ranged between 6 and 21% (mean 11%). In a separately performed combined assay for lymphocytes with membrane-bound immunoglobulins (M-Ig) and lymphocytes, which form rosettes with complement-coated bacteria (BC-RFC), four different fractions of lymphocytes could be detected: (M-Ig+-BC+, M-Ig+-BC-,M-Ig--BC+, M-Ig--BC-). These results suggest that the subpopulation of lymphocytes with complement receptor sites overlaps with, but is not totally identical with the lymphocyte subpopulation bearing Ig on the surface.