Abstract: Objective To improve collecting efficiency , we investigated the changes of blood cells and influencing factors of collecting mononuclear cells from peripheral blood before CAR-T treatment. Methods MNC cells were collected from 23 Non Hodgkin's lymphoma patients and 22 healthy donors by using COM.TEC blood cell separator. Routine blood test was performed before and after MNC collection, including red blood cell (RBC), white blood cell(WBC), lymphocyte cell, mononuclear cell and platelet count. The changes of blood cells before and after collection were analyzed. At the same time, the age, height, weight, body mass index (BMI), collection time, white membrane pumping volume, single collection volume, circulation times, single circulation volume, total circulation volume and the final product mononuclear cell count（MNC）were analyzed by multiple linear regression. Results The blood cell count of healthy donors and non-Hodgkin's lymphoma patients decreased after MNC collection（all P<0.05）; Multiple linear regression analysis showed that the pre-collection MNC, single collection volume and cycle times were closely related to the final product MNC (all P<0.05). However, age, height, weight, BMI, systemic circulation blood volume, and flow rate, had no significant correlation with the final product MNC (all P>0.05). Conclusion sIn order to ensure the health level of patients and healthy donors, we should make individual collection plan for different recipients. The volume of single collection, the number of cycles and the count of pre-collection monocytes cells are the main factors for the efficiency of MNC collection.

Key words: Non Hodgkin's lymphoma, CAR-T treatment, COM.TEC Blood cell separator, Peripheral blood mononuclear cell