Abstract
Assay systems with erythrocytes sensitized by three different human anti-Rh isoantibodies, anti-Rh Ri, Lor and 3360 have been compared for their sensitivity and specificity in detecting Fc receptor-bearing lymphocyte-like cells. When carefully standardized, all these test systems detected primarily the 'third lymphocyte-like cell type', different B and T lymphocytes as detectable by conventional membrane markers.