Rheumatoid Arthritis In Patients With Serum Proteomics

Part one Discovery of New Rheumatoid Arthritis Biomarkers Using the Surface-Enhanced Laser Desorption/Ionization Time-of-Flight Mass Spectrometry Approach【Abstract】:Objective.To identify serum protein biomarkers specific for rheumatoid arthritis(RA),using surface-enhanced laser desorption/ionization time-of-flight mass spectrometry(SELDI-TOF-MS) technology.Methods.A total of 67 samples from RA patients and 50 samples from healthy controls were collected, frozen at -80℃until thawed specifically for SELDI-TOF-MS analysis.Proteomic fingerprinting of serum were identified and analyzed by Biomarker Wizard Software and Biomarker Patterns Software.A decision tree model that represented the highest sensitivity and specificity for differentiating RA patients from healthy controls was selected.Results.The most discriminative mass/charge(m/z) values serving as potential biomarkers for RA were identified in low molecular mass range and high molecular mass range respectively.From among several candidates,the following peaks were highlighted:m/z values of 5842.794,32013.67,11501.75,11716.16 were significantly elevated in RA group,and m/z values of 8569.756,3936.001,4155.924, 4173.434,46769.7 were significantly reduced in RA group.A decision tree model with 6 discriminative peaks was generated by Biomarker Patterns Software on the basis of lowest relative cost of misclassification.A new group of RA patients and healthy controls were introduced to verify the model,and a sensitivity of 93.75%and specificity of 85.71%were observed.Conclusions.Our discriminative model could recognize RA patients from healthy controls with satisfying sensitivity and specificity. Some peaks corresponded well with published similar studies.Verify the model against large samples would pave the way for its ultimate application in clinical practice;and further identification of the recognized proteins would benefit overall understanding of RA pathophysiology.Part two Use of SELDI-TOF-MS to Identify Protein Biomarkers of RA subgroups【Abstract】Objective.To identify a panel of candidate protein biomarkers of rheumatoid arthritis(RA) that can predict disease activity,responsiveness to MTX therapy,erosive disease and pulmonary interstitial disease of RA.Methods.Samples from part one were put into following subgroups if corresponding standards were met.①Patients who attained good improvement and moderate improvement based on DAS28 score during 5 month's follow-up were evaluated both at active and remissive state.Proteomic fingerprinting of both states were mapped,and potential protein biomarkers associated with disease activity were selected on basis of paired-t-test.②Proteomic fingerprinting of patients who had been responsive to MTX therapy and patients who had been irresponsive to MTX therapy were compared in search of potential predictor of MTX therapy responsiveness.③Proteomic fingerprinting of patients with RA pulmonary interstitial disease and patients without lung complications were compared in search of potential biomarkers of RA interstitial pulmonary disease.④Proteomic fingerprinting of patients with erosive disease and non-erosive disease were compared in search of potential biomarkers specific for RA erosive disease.Results.Six protein markers were identified to be significantly correlated with disease activity,which included m/z values of 10268.8,11716.1, 15128.9,28115.4,29063.6,and 44069.2.Several potential protein markers of MTX therapy responsiveness were recognized,some were up-regulated in the irresponsive group,like m/z values of 4172.623,3371.871,4151.792,3441.372,46858.87, 2739.228,15119.91,3157.822,9735.814,7569.996,24123;some were up-regulated in the responsive group,like m/z values of 5328.78,10275.08,4647.921,15927.04, 28116.22.Furthermore,m/z charges of 4303.191,5906.034,6111.997 were significantly up-regulated in erosive RA group,while m/z charges of 39439.3, 46669.33,23443.11,47862.89 were significantly elevated in non-erosive disease group.Candidates for biomarkers of RA pulmonary interstitial disease included those which were significantly higher in lung complication group(11381.34Da,45766.36Da) and those which were significantly higher in lung complication free group(6207.904Da,4094.38Da,4649.487Da,5220.168Da,5641.309Da).Conclusions. The efficacy of these candidates for subgroup biomarkers should be verified in large samples.Identification of key proteins could prompt us into further understanding of RA pathophysiology and may reveal new treatment target.