The Phenotype And Function Of B Cells In Peripheral Blood Of Patients With Diffuse Large B Cell Lymphoma

Background Diffuse Large B-cell Lymphoma(DLBCL)is the most prevalent subtype of malignant lymphoma in adults,caused by the clonal proliferation of B cells.Changes in the phenotype and functions of B cells play a crucial role in the pathogenesis of DLBCL.Tumor staging and viral infections are important for the determination of therapies and the evaluation of prognosis in patients with DLBCL.The application of rituximab plus cyclophosphamide,doxorubicin,vincristine and prednisone(ie R-CHOP regimen)has significantly improved the survival of DLBCL patients,but the therapy may affect the immune status of the patients.It was reported that the number of peripheral blood B cells in DLBCL patients has significantly increased.However,the changes of various B cell subsets,especially those newly discovered,have not been fully elucidated in DLBCL patients with different states.In B cell malignancies,B cell functions can be changed,one of which is the change in the transduction of B cell receptor(BCR)signaling.Currently,we are not fully aware of the changes in the activation of different B cell subpopulations in DLBCL.This study aimed to analyze the B cell composition in peripheral blood of DLBCL patients,to compare the effects of disease staging or viral infection on the composition of peripheral blood B cell subsets,and to analyze the changes in B cell composition caused by R-CHOP therapy.At the same time,we investigated the activation of B cells in DLBCL patients by detecting early signaling transduction of BCR.Methods We collected intravenous anticoagulant blood samples from DLBCL patients and healthy donors,and sorted out the patients’ clinical information.We clarified the tumor stages of the patients,and checked their viral infections,as well as their therapies and treatment stages.Peripheral blood mononuclear cells(PBMCs)were separated.Then the phenotype of B cells was analyzed by multicolor flow cytometry.Ionomycin,anti-Ig M or anti-Ig M+anti-CD40 was added to stimulate peripheral blood B cells of the patients and healthy controls to detect calcium mobilization.Therefore,we can observe the activation of the BCR signaling pathway.Results Although there was no significant difference in the number of total B cells between DLBCL patients and healthy controls,B cell composition of the patients changed.In patients with DLBCL,the number of unswitched memory B cells decreased,while the number of switched memory B cells increased.The number of plasmablasts was elevated.Interestingly,the newly discovered atypical B cells also increased in the peripheral blood of patients.There were differences in B cell subsets in DLBCL patients with different tumor stages.Transitional B cells in DLBCL patients with hepatitis B virus(HBV)infection were lower than those of patients without HBV infection.R-CHOP therapy can cause changes in the composition of peripheral blood B cells in DLBCL patients.Studies on the activation function of BCR showed that the release of calcium from the endoplasmic reticulum of the patients’ naive B cells was higher than that of healthy controls.Conclusions In terms of phenotype,peripheral blood B cell subpopulations of DLBCL patients were different from those of healthy individuals.There were differences in B cell subsets of DLBCL patients with different tumor stages.Some peripheral blood B cell subsets of DLBCL patients with HBV infection had also changed.R-CHOP therapy can affect the composition of B cells in the patients’ peripheral blood.B cell phenotype may be of reference value for the choice of therapies and the evaluation of prognosis in patients with DLBCL,and may be suggestive for the assessment of the immune status of patients.Functionally,the activation of the BCR signaling pathway of peripheral blood B cell subsets in patients with DLBCL was abnormal,which may be important for understanding the role of BCR signaling in the pathogenesis of DLBCL.