The Study Of N-glycans In Serum Immunoglobulin Of Autoimmunity Disease Patients

Objective:In our study,an advanced and sensitive method based on ESI-MS was employed to profile N-glycans in serum immunoglobulin of autoimmunity disease patients and healthy controls.The aim was to analyse the aberrant N-glycosylation and the value of diagnosis for autoimmunity disease,and reveal the roles of N-glycans in immune system.Methods:?1?Acquiring the total Ig and IgG from SS,SLE,RA patients and healthy controls by saturated ammonium sulfate and Protein G,respectively;?2?Extraction and purification of N-glycans with PNGase F;?3?Quantitative and qualitative analysis of N-glycans by Mass Spectrometry;?4?Statistically analyse the changes of N-glycans in total Ig and IgG,and the correlations between the aberrant N-glycans with corresponding autoantibodies,and then analyse the value of diagnosis.Results:?1?The aberrant N-glycans in IgG:31 N-glycans were identified.We found G0 and Core fucosylated N-glycans increasing significantly while Sialylated N-glycans decreasing in all three AIDs,and Highmannose decreasing in SS and RA.The N-glycans changed more obviously in corresponding patients with positive autoantibodies.And the values of AUC were all over 8.0 which showed the resultful value for AID diagnosing.?2?The aberrant N-glycans in total Ig:38 N-glycans were identified.We found G0increasing significantly while Sialylated and Bifucosylated N-glycans decreasing in both SS and SLE.Core fucosylated and Highmannose N-glycans increased only in SS.MSⁿ analysis showed the sialic acid linked by?2,6 while the structures of Bifucosylated N-glycans contained with Lewis X and H2,and the value of AUC of Bifucosylated was0.825.Conclusion:N-glycosylation played a important role in structure maintenance and activity regulation of immunoglobulin,there were some new discoveries about N-glycans in our study.Core fucosylated N-glycans increased while?2,6-Sialylated decreased in patients,and the N-glycans changed in different levels in the three autoimmunity diseases.In additional,the Bifucosylated N-glycans with structures of Lewis X and H2 decreased significantly in patients.ROC analysis showed a high value of these aberrant N-glycans for AID diagnosing.In conclusion,with previous studies,the aberrant N-glycosylation could influence the affinity between Ig and FcR,and was important for anti-inflammatory and pro-inflammatory activity.Our study was of great significance for the mechanism research and clinical diagnostic of autoimmune disease.