Glycobiom Lymphocytes Surface Study of Patients with B-Cell Chronic Lymphocytic Leukemia

Abstract

The purpose of the study was to investigate the intensity of exposure of peripheral blood lymphocyte surface glycans in patients with B-cell chronic lymphocytic leukemia by measuring the density of lectin- or antigen-positive epitopes under antitumor therapy in order to evaluate it for a more reasonable selection of qualitative and quantitative composition of therapy. Materials and methods. The objects of the study were blood lymphocytes of patients with chronic lymphocytic leukemia (n=15) aged 58-66 years before and after a course of standard chemotherapy according to the COP scheme. The control group consisted of healthy volunteers (n=15) aged 55 to 65 years. Isolation of lymphocytes was performed by a modified method of A. Boyum. Polyclonal antibodies to α1-acid glycoprotein and fibronectin were used. Exposure to Tn antigen and CD43 on blood lymphocytes was determined with secondary antibodies to mouse immunoglobulins conjugated to FITC (Millipore, USA). To study the exposure of glycans on the surface of lymphocytes, we used a set of seven lectins labeled with FITC. Data recording was performed on a Beckman Flower EPICS flow cytometer. Processing of the results was done using the program FCS3 Express. Results and discussion. Compared with the group of hematologically healthy donors on the surface of lymphocytes in patients with chronic lymphocytic leukemia, a 20-fold increase in the density of exposure to ConA epitopes, 10 times – UEAI- and SNA-positive epitopes were shown; MAA II epitope, Tn, and CD43 antigen densities were increased 100-fold (p <0.01). Exposure densities of MAA II-, Tn-, and CD43-positive epitopes on the plasma membrane of lymphocytes in patients with chronic lymphocytic leukemia receiving alkylation therapy decreased 10-fold relative to treatment data, but remained 10-fold higher than in the group of healthy hematologists. Conclusion. On the plasma membranes of lymphocytes in patients with chronic lymphocytic leukemia, the density of exposure of mannose and neuraminic acid residues was significantly increased. COP therapy reduced the density of these epitopes to control values. A significant increase in the density of carcinogenesis markers – Tn- and CD43-antigens on the plasma membranes of lymphocytes in patients with chronic lymphocytic leukemia has been shown. COP therapy provided only a partial decrease in their density, which indicates the insufficient effectiveness of COP therapy, its inability to completely stop the oncological process in patients with chronic lymphocytic leukemia