A Preliminary Study On Adaptive Immune Cells Reconstruction Of β-Thalassemia Major After Transplantation

Objective:Constructing the fitting equation and curve of adaptive immune cell reconstitution in patients with severeβ-thalassemia after allogeneic hematopoietic stem cell transplantation.Objective to predict and simulate the process of adaptive immune cell reconstitution,and to explore the rules and influencing factors of adaptive immune cell reconstitution.Methods:observation index:Participants are the 86 patients withβ-thalassemia major after allogeneic hematopoietic stem cell transplantation from January 2018 to December2018 in Shenzhen Children’s Hospital.Collecting the basic information of patients and the information relevant to the transplantation,then selecting the 1st,3rd,6th,12th and the 18th month after transplantation as the monitoring time points for data collection to make 5 times measurements.Recording the absolute count of total T cells,CD4~+T cells,CD8~+T cells and B cells at those monitoring time points and recording the types and time of complications during the observation period.Analysis methods:SAS 9.4 software was used to construct the fitting equation of adaptive immune cell reconstruction in mixed effect model.The basic information of patients and common postoperative complications were included as independent variables,then analyzing the influencing factors of adaptive immune cell reconstitution by mixed effect model.The cumulative incidence rate of postoperative complications that affect the adaptive immune cells was calculated to describe their time distribution rule.Results:1.The equation and law of adaptive immune cell reconstruction:the equation of CD4~+T cells:y=89.1038+0.5989t+0.00181t~2(15≤t≤600),the expected value showed a monotonic increasing trend with time,which reached the reference range for the first time at the 284th day after transplantation and remained within the reference range until the end of the observation period;the equation of CD8~+T cells:y=527.2+0.00814t~2-0.00001t~3(15≤t≤600),the expected value increased first and then decreased with time,which reached the reference range at the beginning of the observation period and was higher than the reference range from the 367th day after transplantation to the end of the observation period;the equation of total T cells:y=684.08+0.01399t~2-0.00002t~3(15≤t≤600),the expected value first increased and then decreased with time,which reached the reference range at the 55th day after transplantation for the first time,reached the maximum at the 466th day after transplantation,within the reference range until the end of the observation period;the equation of B cells:y=125.24+1.1632t(15≤t≤600),the expected value increased monotonously with time,reaching the reference range at the beginning of the observation period and exceeding the reference range from the 422th day after transplantation to the end of the observation period.2.Influencing factors of adaptive immune cell reconstitution:The speed of CD4~+T cells reconstitution is relevant to the age of the patients and the donor source;The speed of CD8~+T cells reconstitution is relevant to engraftment syndrome and oral mucositis;The speed of B cells reconstitution is relevant to engraftment dysfuction.3.Implantation syndrome is more common in the first 21 days after transplantation,and the incidence rate is 55.81%.Oral mucositis is most commonly seen in 17 days after transplantation,the incidence rate is41.86%.Implantation dysfunction occurred within 1 years after transplantation,and the incidence rate was 9.3%in the first 3 month.Conclusion:1.We successfully constructed the fitting equation of T and B cells reconstitution,which can be used to predict the level of adaptive immune reconstitution inβ-thalassemia major children after transplantation.2.The reconstruction rate of T and B cells in children withβ-thalassemia after allogeneic hematopoietic stem cell transplantation is different,but it is generally earlier than that in adults,and can reach the normal level within one year after transplantation totally.3.The younger patients own the faster reconstruction speed.What’s more,the relative donor is beneficial to adaptive immune reconstitution after transplantation.4.The reconstitution speed of CD8~+T cells is related to implantation syndrome,and the reconstitution speed of B cells is related to implantation dysfunction.