Fractional Exhaled Nitric Oxide Levels In Rheumatoid Arthritis Associated Interstitial Lung Disease

Rheumatoid arthritis(RA)is a major involvement of joints,but also can cause cartilage and bone,symmetry and erosive destruction of systemic autoimmune diseases,in addition to involving in many organs,such as heart,lung,gland and skin etc.The study showed that the prevalence of extra-articular manifestations of disease was 40%.Lung involvement is particularly common,with potential effects on serosal,airway,and/or parenchymal tissue.While the most common and concealed,also the most destructive is interstitial lung disease,age of onset is usually at the age of 50-60.Rheumatoid arthritis associated with interstitial lung disease is often occult,that is an irreversible lung disease.The quality of life in advanced patients is very poor.Studies have shown that nitric oxide is associated with the pathogenesis of pulmonary fibrosis.In addition,the level of nitric oxide in early pulmonary inflammation is elevated.And it was found that the levels of nitric oxide,nitrite and nitric oxide synthase in patients with rheumatoid arthritis were higher than those of normal people.Fractional exhaled nitric oxide(FeNO)as a new means for detection of airway inflammation,has the advantages of simple and practical,rapid,reproducible,has been widely used in asthma and chronic obstructive pulmonary disease,pneumoconiosis,connective tissue disease among a variety of interstitial lung disease,pulmonary artery hypertension and so on,this study aims to analyze fractional exhaled nitric oxide levels in rheumatoid arthritis related changes of interstitial lung disease,to identify whether it can be used for early identification and monitoring of the disease,and to provide help for the clinical work.Objective: To investigate the relationship between fractional exhaled nitric oxide and the occurrence and development of interstitial lung disease associated with rheumatoid arthritis,and to clarify its clinical value.Methods: There are seventy-two patients with rheumatoid arthritis.All patients performed the high resolution CT,Doppler echocardiography,pulmonary function,blood gas analysis and inspection.The DAS28-ESR scoring system was used to assess the condition of the disease.The degree of pulmonary interstitial lesions was evaluated according to the CT performance.According to whether the patients with interstitial lung disease(ILD)or not,with pulmonary hypertension(PAH)or not,they were divided into simple rheumatoid arthritis group(RA group),rheumatoid arthritis with interstitial lung disease group(RA-ILD group),rheumatoid arthritis complicated with interstitial lung disease and pulmonary hypertension group(RA-ILD-PAH group).At the same time,20 healthy persons who were admitted to our hospital in the same period were selected as the control group.All subjects underwent fraction exhaled nitric oxide detection.All the data were statistically analyzed with SPSS19.0 software.Results:1 Fractional exhaled nitric oxide levels were significantly higher in RA patients with ILD than RA patients,RA patients with ILD and PAH,control subjects(P<0.05),significantly higher in RA patients than RA patients with ILD and PAH,control subjects(P<0.05),lower in RA patients with ILD and PAH than control subjects(P>0.05).2 The alveolitis score in RA patients with ILD was higher than that in RA patients with ILD and PAH patients(P<0.05),the pulmonary fibrosis score in the two groups was the opposite(P<0.05).3 There was a positive correlation between fractional exhaled nitric oxide levels and alveolitis score in RA patients with ILD(including with PAH)(P<0.05).4 There was a positive correlation between fractional exhaled nitric oxide levels and DAS28-SER score(P<0.05).5 There was a significant inverse correlation between fractional exhaled nitric oxide levels and pulmonary arterial systolic pressure(r=-0.452,P<0.05).Conclusions:1 The dynamic monitoring of fractional exhaled nitric oxide can assist the early diagnosis of rheumatoid arthritis with interstitial lung disease and the patient's condition monitoring.2 Fractional exhaled nitric oxide levels can be used as a clinical indicator for assessing the degree of disease activity in rheumatoid arthritis.3 Fractional exhaled nitric oxide levels may become a monitoring and evaluation index of the pulmonary arterial hypertension.