Аннотация:The spleen is the largest peripheral organ of the immune system. Thestandard volume of lymphodissection in stomach cancer during gastrectomyor proximal resection is D2, which implies splenectomy. Immunity disordersin patients after splenectomy primarily affect the B cell immune response.Peripheral blood B-lymphocytes subpopulations have been studied in patientswith gastric cancer. Group 1 - patients with gastrectomy, D2 lymphodissection,group 2 - patients with gastrectomy, D2-lymphodissection, splenectomy.Evaluation of the expression of antigens (CD20, CD21, CD23, CD38, HLA-DR,CD71, CD10, CD95, CD25, CD5, CD56, κ- and λ-light was performed in thegate of CD19+ cells. Among peripheral blood lymphocytes the presence ofCD19+CD5+ B cells (B1a cells), some of which express the activation antigensCD38 and CD23 is found; a small part of CD5+ B cells is CD25+CD38−. Thenumber of CD23+ cells ranged from 25 to 40% in different patients. A significantnumber of B cells with a low level of CD21+ expression were detected. Ingroup 2 after surgery, the percentage of cells with CD5+ expression significantlyincreased, the relative amount of CD19+ lymphocytes, CD19+CD21+ B cellsdecreased. Given data on B1 and BMZ populations, this can lead to a weakeningof both general and antitumor immunity.