The Characteristics Of Peripheral Nk Cells And Its Clinical Roles In Patients With Sj?gren's Syndrome And The Clinical Value Of Diffusion Weighted Imaging Of Mri For Evaluating The Parotid Gland Lesions In Patients With Sj?gren's Syndrome

Backgrounds:Sj?gren's syndrome?SS?is a systemic autoimmune disease that mainly invades the exocrine glands such as salivary glands and lacrimal glands.Its etiology and pathogenesis are still unclear.Early studies tended to focus on adaptive immunity,but recent studies have found that innate immunity also plays a role in the pathogeneses of SS.NK cells are a kind of cytotoxic lymphocytes,which are the key components of innate immunity.They can not only exert direct cytotoxic effects,but also secrete immunoregulatory cytokines and chemokines,linking innate immunity to adaptive immunity.Some studies have examined the proportion and absolute number of peripheral blood NK cells in patients with SS,but the results are not consistent.Up to now,only few studies analyzed the subpopulation variations as well as the clinical significance of NK cells in SS.Objective:To investigate the characteristics of peripheral blood NK cells and its clinical roles in patients with SS.Methods:We prospectively recruited 52 patients clinically suspected of having SS and collected the peripheral blood samples with informed content.These patients subsequently fulfilled the 2002 AECG criteria or 2012 ACR criteria for pSS and were compared to 20 healthy volunteers.We determined and compared the proportion,absolute counts,function and surface molecules of NK cells and their constituent CD56 subsets in peripheral blood samples using flow cytometry.The effects of treatment on NK cells were also investigated.The ROC curve was used to assess the diagnostic value of the ratio of CD56^brightNK to CD56^dimNK.Results:The proportion of peripheral blood NK cells and their CD56^dim subset and the absolute counts of peripheral blood NK cells and their constituent CD56 subsets were significantly decreased,while the proportion of CD56^bright subset and ratio of CD56^brightNK to CD56^dimNK were significantly increased in pSS patients compared to that in healthy controls.The expression of surface inhibitory receptor CD158b of CD56^dim subset was decreased and the ability of degranulation of NK cells was enhanced in pSS patients compared to that in healthy individuals.Decreased blood CD56^dimNK was rebounded in the pSS patients after treatment,with the decreased ESSDAI and serum IgG level.ROC curve analysis indicated that the area under the curve?AUC?of the peripheral blood CD56^brightNK/CD56^dimNK was 0.838,and the best diagnostic cut-off point was 0.0487for pSS patients.Conclusion:The proportion and the absolute counts of CD56^dim subset in peripheral blood of pSS patients were decreased.The ability of degranulation of CD56^dim subset was enhanced,which may be related to the decreased expression of surface inhibitory receptor CD158b.The absolute counts of CD56^dim subset of blood NK cells may have a certain feasibility in the evaluation curative effect of pSS patients.The ratio of blood CD56^brightNK to CD56^dimNK is valuable to identify the condition of pSS.Backgrounds:Sj?gren's syndrome?SS?is a multisystem involved autoimmune disease that mainly involves the exocrine glands such as salivary glands and lacrimal glands.Different classification criteria have been applicated for diagnosing SS,which require a combination of multiple examination results.However,in clinical practice,some difficulties still exist in the process of diagnosis of SS.Therefore,it is necessary to explore a safe and non-invasive methods to evaluate parotid gland lesions of SS.Diffusion-weighted imaging?DWI?is an emerging functional imaging technology that can be calculated as the apparent diffusion coefficient?ADC?for quantitative analysis.In recent years,the DWI has been used for parotid gland function assessment.However,there are few studies evaluating the clinical value of this index in parotid lesions in SS patients.Objective:To investigate the clinical value of DWI in the evaluation of parotid gland lesions in patients with SS.Methods:This study included SS?n=19?,non-SS?n=8?patients with oral and ocular dryness diagnosed by 2002 AECG criteria in Tongji Hospital from March 2015 to May 2017 and 32 health volunteers.DWI scan of parotid glands was performed and quantified by the apparent diffusion coefficient?ADC?.The ADC values were compared,and its correlation with disease activity index were analyzed.The ROC curve was used to assess the diagnostic value of ADC.We also compared the different value of DWI and SPECT imaging in the evaluation of severity of affected parotid glands in SS patients.Results:The ADC values of parotid glands were significantly higher in SS patients than those in healthy control group and non-SS group.The ADC value was positively correlated with EULAR Sj?gren's syndrome Disease Activity Index?ESSDAI?in SS group?r=0.535,p<0.05?.ROC curve analysis indicated that the AUC was 0.764,and the best diagnostic cut-off point of ADC value was 749×10-6 mm2/s for SS patients.The sensitivity,specificity,Youden index,and agreement rate of DWI were 100%,50%,0.5 and 84% while these indexes of ECT were 88.2%,37.5%,0.279,and 72%,respectively.Conclusion:DWI is valuable to reveal the parotid gland involvement in patients with SS,and its ADC value was positively correlated with the disease activity.Thus,DWI may have a certain feasibility in the evaluation of parotid gland lesions in SS patients.