Enumeration of TG lymphocytes in B-chronic lymphocytic leukaemia (B-CLL) by a rapid double-rosetting technique.

T lymphocytes bearing the Fc receptors for IgG (E+ F c gamma + or TG cells) in 38 patients with B-cell chronic lymphocytic leukaemia (B-CLL) were quantified by a simple one-step double-rosette technique. This assay detects the TG lymphocytes from total peripheral blood mononuclear cells (MNC) on the basis of their capacity to bind simultaneously sheep red cells and chicken erythrocytes sensitized with anti-CRBC rabbit IgG. The data obtained were comparable to those evaluated by the more elaborate conventional two-step method, which requires initial T-cell purification. The double-rosette technique is specific for T cells and it may be adapted as a routine clinical laboratory assay for TG cells in B-CLL patients who have very low T/B cell ratio owing to clonal expansion of B cells.