The Clinical Study About Short-Term Influence Of Chest Radiography In Anteroposterior Position On Pneumonic Neonatal Immune Functions

Background and ObjectivesThe viewpoint that radiography unavoidably brings on damage to the subjects, especially the immune organs such as thymus,spleen and lymph node has dominated most people for a long period of time.They also hold the viewpoint that radiography is dangerous to the neonate since the immune system of the neonate is immature and is sensitive to the radioactive ray.All the above have restricted the application of radiography in the neonate.However,the incident dose of chest radiography in anteroposterior position for the neonate is less than 1 mGy,which is presumed to be low dose irradiation(LDR).Cumulative researches has revealed that suitable LDR has the potential to induce immunopotentiation(i.e.,irradiation hormesis).The goal of this study is to investigate the short-term impact of chest radiography in anteroposterior position on pneumonic neonates' immune functions through detecting T cell subset,immunoglobulin and Dipeptidyl Peptidaseâ…£/CD26(DPPâ…£/CD26)and to provide scientific proof for appropriate selection of chest radiography and for the clinical utilization of LDR.MethodsFrom September 2006 to May 2007,a total of 64 neonates with pneumonia who were admitted by Department of pediatrics in Qilu Hospital of Shandong University were selected.All the neonates were divided randomly into either the experimental or the control group.The experimental group consisted of 19 boys and 16 girls while in the control group 18 were male and 11 were female.There were no obvious statistical differences between the two groups in sex,gestation age,age,weight and the period from the onset of pneumonia to being admitted(P＞0.05).The neonates in the experimental group were tested by chest radiography in anteroposterior position on the second day after they were admitted.Serum samples were collected from all the neonates on the 1^st,3^rd,7^thday after the admission and 42^ndafter birth from femoral vein.The flow cytometry,rate nephelometry assay and colorimetric method were employed to detect the T-lymphocyte subpopulation(CD3⁺T%,CD4⁺T%,CD8⁺T%, CD4⁺T/CD8⁺T),humoral immunity indexes(IgG,IgM,IgA)and DPPâ…£/CD26 separately.Results1.Comparing the control group,the CD3⁺T%and CD4⁺T%of the experimental group before and 1 day after the chest radiography(1 and 3 days after the admission)had no statistical significance(P＞0.05),but both increased 5 days after the chest radiography(7 days after the admission)and 42 days after birth(P＜0.05).The CD8⁺T%and CD4⁺T/CD8⁺T did not show obvious differences at all the time points(P＞0.05).The tendencies of CD3⁺T%and CD4⁺T%in the experimental group were different from the control group.2.Comparing the control group,the immunoglobulin(IgG,IgM)of the experimental group changed little(P＞0.05).The statistical analysis of IgA was not carried out on account of too many missing.3.Comparing the control group,the DPPâ…£/CD26 level of the experimental group before the chest radiography had no statistical significance(P＞0.05).The DPPâ…£/CD26 level decreased significantly 1 day after the radiography(P＜0.05), and increased significantly 42 days after birth(P＞0.05).The tendency of DPPâ…£/CD26 in the experimental group was different from the control group. Conclusions1.The chest radiography in anteroposterior position has obvious stimulation effect on the cellular immune indexes(CD3⁺T%,CD4⁺T%)of the neonate with pneumonia in a short period of time,which can promote T lymphocyte in peripheral blood to mature and differentiate.2.The chest radiography in anteroposterior position has no obvious effect on humoral immunity indexes(IgG,IgM)of the neonate with pneumonia in a short period of time3.The chest radiography in anteroposterior position has inhibition-stimulation effect on the DPPâ…£/CD26 levelof the neonate with pneumonia in a short period of time.