Comparison of some lymphocyte markers in B-cell chronic lymphocytic leukaemia and systemic lupus erythematosus (the B lymphocyte subset).

Spontaneous mouse red-cell rosette formation (M-rosette), Leu 1 (CD 5) monoclonal antibody binding, ecto-nucleotidase enzyme reactions and mitogen responses of peripheral blood lymphocytes in 10 patients with B-cell chronic lymphocytic leukaemia (CLL), in 8 with systemic lupus erythematosus (SLE) and in 10 controls were studied. The numbers of Leu 1 (CD 5) positive B lymphocytes in CLL and SLE were higher than in controls. These are called "autoregulatory" B lymphocytes, which are thought to be independent of T-cell regulatory effects. A significant increase of mouse rosette forming cells (MRFCs) was found in CLL, while in SLE and in controls their number was low. Compared to the B lymphocytes of SLE patients and controls, those of CLL patients showed diminished responses to pokeweed mitogen stimulation parallel to their decreased level of 5'-nucleotidase. Correlations between these markers and the features of isolated M-rosette positive CLL B lymphocytes are discussed.