| Objective:In this study,we compared the changes in peripheral immune cells and their correlation with neuropsychological scales in patients with Alzheimer’s disease（AD）,mild cognitive impairment（MCI）,and control group（CG）;and Combined with 18F-Fluorodeoxyglucose(18F-FDG)and 18F-AV45(18F-florbetapir)PET-CT test results to further explore the correlation between peripheral immune cells and glucose metabolism（FDG）and the degree of beta-amyloid（Aβ）load in AD pathology（A+）and non-AD pathology（A-）,in order to investigate the role of peripheral immunity in the involvement of AD pathology and the possibility of peripheral immune cells as biomarkers for early clinical diagnosis and disease assessment.Materials and Methods:This was a retrospective study and the study was approved by the hospital ethics committee.The study population was divided into the AD group,MCI group,and CG.Patients were selected from the Department of Neurology of the First Affiliated Hospital of Dalian Medical University from April 2015 to November 2022.According to the inclusion and exclusion criteria,70 patients with AD were selected,and 34 cases underwent 18F-FDG PET-CT and 18F-AV45 PET-CT scans respectively(18F-AV45 PET-CT was numerically normalized using cerebellar brain regions as the reference brain regions,and each region of interest（ROI）radioactivity was determined as positive compared to the database.（1.65 standard deviations higher than the mean value of each ROI in the database was judged as positive performance）,including 23 cases of A+patients and 11 cases of A-patients;a total of 26 cases of MCI patients,including 8 cases of 18F-FDG PET-CT scans;and 50 cases of CG.All patients with AD and MCI underwent detailed clinical data,neurological examination,peripheral blood immune cell index,and neuropsychological scale examination.These included age,sex,disease duration,education,white blood cell count（WBC）,neutrophil count（NEU）,lymphocyte count（LY）,monocyte count（MONO）,neutrophil to lymphocyte ratio（NLR）,neutrophil count%（NEU%）,lymphocyte count%（LY%）,eosinophil count（EO）,eosinophil count%（EO%）,eosinophils-lymphocyte ratio（ELR）,eosinophils%-lymphocyte%ratio（EO%/LY%）;The neuropsychological scales included Mini-Mental State Examination（MMSE）,Montreal Cognitive Assessment（Mo CA）,and Activity of Daily Living Scale（ADL）.The PET-CT images were analyzed using Neuro Q software.Statistical analysis was performed using SPSS 26.0 software,and P<0.05 was set to be statistically significant.Results:1.Comparison of general information of AD group,MCI group,and CG:There was no statistical difference between the three groups in terms of age of attendance,gender,and education level（all P values>0.05）;there was no statistical difference between the AD and MCI groups in terms of age of onset,age of attendance,gender,education level,and duration of disease（all P values>0.05）;the MMSE and Mo CA scale scores in the AD group were smaller than those in the MCI group,and the ADL scale scores in the AD group were higher than those in the MCI group,and the difference was statistically significant（all P values 0.000）.The differences were statistically significant（all P values were 0.000）.2.Comparison of peripheral immune cells in the AD,MCI,and CG groups and diagnostic efficacy:The differences in NEU%and NLR in the AD group and MCI group,and NEU%,NLR,LY,and LY%in CG were statistically significant（P value<0.05）,with NEU%and NLR in the AD group being higher than those in the MCI group and CG（P values 0.012,0.019,0.000,0.000,respectively）,and LY and LY%in the AD group were lower than CG（both P values 0.000）,and there were no statistically significant differences in WBC,NEU,MONO,EO,EO%,ELR,and EO%/LY%（P value>0.05）;there were no significant differences in peripheral immune cells in the MCI group compared with CG（P values>0.05）.The AUC for identifying NLR and NEU%in AD group and MCI group was 0.704 and 0.687,respectively（P value 0.002 and 0.005,respectively）.3.Correlation between peripheral immune cells and neuropsychological scales in AD and MCI patients:There was no correlation between NEU%,NLR,LY,and LY%and MMSE score,Mo CA score,and ADL score in the AD and A+groups（all P values>0.05）,positive correlation between NLR and NEU%and MMSE score in the A-group（r=0.661,P=0.027,r=0.735,P=0.010）,negative correlation between LY%and MMSE score（r=-0.691,P=0.018）,and no correlation between LY and MMSE score,Mo CA score,and ADL score（all P values>0.05）.LY and LY%were negatively correlated with MMSE scores（r=-0.440,P=0.025,r=-0.526,P=0.006）,and NLR and NEU%were positively correlated with MMSE scores in the MCI group（r=0.501,P=0.009,r=0.453,P=0.020）,and LY,LY%,NLR,NEU%did not correlate with Mo CA scores and ADL scores（all P values>0.05）.4.Correlation between peripheral immune cells and the degree of FDG metabolism in functional brain areas in the AD group:LY in the AD group,LY and LY%in the A-group correlated with the degree of FDG metabolism in 2 brain functional areas,respectively;LY,NEU%,LY%,and NLR in the A+group all correlated with the degree of FDG metabolism in multiple brain functional areas（all P values<0.05）.5.Correlation between peripheral immune cells and the degree of FDG metabolism in functional brain areas in the MCI group:LY,NEU%,LY%,and NLR in the MCI group all correlated with the degree of FDG metabolism in multiple functional brain regions（all P values<0.05）.6.Correlation between peripheral immune cells and the degree of Aβload in functional brain areas in the AD group:LY,NEU%,LY%,and NLR in the AD and A+groups correlated with the degree of Aβloading in the bilateral thalamus and bilateral caudate nucleus,respectively（all P values<0.05）.NEU%,NLR,LY,and LY%in the A-group did not correlate with the degree of Aβloading in each functional brain region（all P values>0.05）.Conclusion:1.There were significant differences in NEU%,NLR,LY,and LY%compared with AD,MCI,and CG,and this difference may contribute to the differential diagnosis of AD and MCI,with NLR having better diagnostic efficacy.2.NEU%,NLR,LY,and LY%were not significantly correlated with neuropsychological scales scores in AD patients and were significantly correlated in MCI patients,suggesting that NEU%,NLR,LY,and LY%may have a greater impact on early cognitive impairment.3.NEU%,NLR,LY,and LY%correlated with Aβload in several brain regions in A+patients,and did not correlate with Aβload in all brain regions in A-patients,presumably NEU%,NLR,LY,and LY%may be related to Aβdeposition. |
