Lymphocyte subpopulations in chronic lymphocytic leukemia detected by lectin binding and flow cytometry

Flow cytometry was used to compare binding of wheat germ agglutinin (WGA) and Lens culinaris lectin (Lcl) to peripheral lymphocytes (PBL) from normal subjects and 26 patients with chronic lymphocytic leukemia (CLL). As defined by the interactions of WGA and Lcl with cell surface receptors, normal unfractionated PBL and purified B‐cells were heterogeneous, containing subclasses that bound to WGA (WGA⁺Lcl⁻), Lcl (WGA⁻Lcl⁺), both (WGA⁺Lcl⁺), or neither (WGA⁻Lcl⁻). By contrast, in 25 of 26 CLL patients, PBL were homogeneous with approximately 90% of cells binding one or both lectins. Apparent monoclonal tumor cell populations were identified in these patients corresponding to the normal lectin defined cell subclasses: WGA⁻Lcl⁻ in 18 patients; WGA⁻Lcl⁺ in four patients; WGA⁺Lcl⁺ in three patients. Ten patients were studied sequentially on more than one occasion at intervals of five to 15 months. Lectin binding patterns remained stable within this time frame. These findings demonstrate that lectin binding may detect several CLL subclasses corresponding to lectin‐defined subsets of normal PBL. Lectins can serve as useful tools for dissecting the heterogeneity of human lymphoproliferative diseases.