Receptors for <em>Helix pomatia</em> A haemagglutinin on leukaemic lymphocytes from patients with chronic lymphocytic leukaemia (CLL).

Blood lymphocytes from thirteen patients with CLL were studied for surface-bound Ig (SIg), Fc receptors (EA rosettes), receptors for sheep erythrocytes (E rosettes) and receptors for Helix pomatia A haemagglutinin (FTP), a carbohydrate-binding protein with specificity for N-acetyl-D- galactosamine and related sugars. Fluorescein-labelled HP binds to subpopulations of human peripheral blood lymphocytes (PBL) treated with neuraminidase. In normal peripheral blood, HP binds to the T-lymphocytes while the majority of the B cells bearing surface-bound immunoglobulin do not have receptors for HP. In untreated CLL, HP binds to 90-100% of the neur-aminidase-treated PBL. Almost all of the SIg-positive cells in CLL patients also have receptors for HP. Two groups of patients were found: in one the total fraction of SIg&plus; cells was &les;50% and about 30% of these lost their Ig during incubation at 37° C. No such loss of Slig was revealed in the remaining patients where total SIg&plus;fraction was &ap;70%. These patients usually had higher blood lymphocyte counts, probably reflecting a more advanced disease. CLL patients in remission with low numbers of leukaemic cells also had low numbers of blood lymphocytes carrying both SIg and HP-receptors. It is concluded that leukaemic cells carry both HP receptors and SIg. Testing of this combination therefore provides a valuable new tool for monitoring patients with CLL. [ABSTRACT FROM AUTHOR]