Rosette formation with mouse erythrocytes by lymphocytes from normal donors and patients with various diseases

Rosette formation of human lymphoid cells with mouse erythrocytes has recently been proposed as a marker for a subpopulation of B lymphocytes. In this work we studied the percentage of mouse rosette forming cells (MRFC) in normal and pathological conditions and compared them to the percentage of sheep rosette forming cells (SRFC) a marker for T lymphocytes. Peripheral blood lymphocytes (PBL) from normal donors contained 6.2 +/- 1.1% (mean +/- 1 S.D.) MRFC. High percentages of MRFC were found in CLL patients, and a slight increase was observed in patients with systemic lupus erythematosus. MRFC were absent in Bruton's type agammaglobulinaemia, but were normally present in patients with T cell defects. Cryopreservation of lymphocytes in 10% DMSO did not significantly affect the mean percentages of SRFC and MRFC, though a slight increase of the former and a small reduction of the latter was observed. Double binding experiments on peripheral blood lymphocytes showed a predominant association of MRFC with cells staining for surface IgM and/or IgD. In all samples tested, we also observed a small population of MRFC negative for sIgM or sIgD and a few sIgM or sIgD positive cells that did not rosette with mouse erythrocytes.