The Clinical Significance Of Anti-CCP Antibody Detection In Patients With Rheumatoid Arthritis-associated Interstitial Lung Disease

Objective To investigate the expression level and clinical significance of anti-cyclic citrulline peptide(CCP)antibody in serum of patients with rheumatoid arthritis(RA)complicated with lung interstitial lesion(ILD).Methods A total of 126 patients diagnosed with RA who were hospitalized in the department of rheumatology and immunology of Ningxia hui autonomous region people's hospital from June 2016 to June 2019 and 52 healthy patients who underwent physical examination in our hospital during the same period were collected.Clinical data and laboratory examination results were collected and divided into RA-ILD group,pure RA group and healthy control group according to high-resolution CT(HRCT)results,of which 50 cases were in the RA-ILD group,76 cases in the pure RA group and 52 cases in the healthy control group.Clinical indicators and laboratory examination results of each group were compared.Through binary Logistic analysis and ROC curve,the correlation between anti-CCP antibody and RA-ILD was analyzed and obtain the sensitivity and specificity corresponding to the optimal cut-off value,and the diagnostic value was evaluated according to the area under the curve(AUC)size.Results1.There were 50 patients in the RA-ILD group,including 17 males and 33 females,aged 35-78 years,with an average age of(60.82±8.90)years.There were 76 cases in the RA group alone,including 23 males and 53 females,aged 20-78 years,with an average age of(48.97±12.74)years.The healthy control group included 52 cases,including 15 males and 37 females,aged 18-71 years,with an average age of(46.87±13.94)years.2.The serum anti-CCP antibody level in the RA-ILD group was 163.50(41.13,220.00)U/ml,the serum anti-CCP antibody level in the RA group alone was 52.20(1.65,220.00),and that in the healthy control group was 0.25(0.25,0.68),The difference of the anti-CCP antibody level among the three groups was statistically significant(P =0.00<0.05).The serum anti-CCP antibody of the RA-ILD group was significantly higher than that of the pure RA group,and the difference between the two groups was statistically significant(P=0.016<0.017).The difference between the serum anti-CCP antibody of the RA-ILD group and the healthy control group was statistically significant(P= 0.00<0.05).The difference between the serum anti-CCPantibody of the pure RA group and the healthy control group was statistically significant(P= 0.00<0.05).3.There was no statistically significant difference in anti-ccp antibody level between the gender groups of RA-ILD patients(U=-0.83,P=0.41).4.There was no statistically significant difference in anti-CCP antibody level in the course group of RA-ILD patients(U=-0.38,P=0.71).5.Age,course of disease,number of tender joints,number of swollen joints,ESR,CRP,DAS28 score,and anti-CCP antibody in the RA-ILD group were significantly different from those in the simple RA group(P<0.05),P=0.00,P=0.036,P=0.005,P=0.018,P=0.004,P=0.045,P=0.001,P=0.016,respectively.There was no significant difference in gender,RF,ANA between the RA-ILD group and the RA group.Binary Logistic regression analysis showed that age,DAS28 score and anti-CCP antibody were independent risk factors for RA-ILD(P<0.05).6.By drawing ROC curve,the optimal cut-off value of anti-CCP antibody in RA-ILD was 86.85,corresponding specificity was 59.20%,sensitivity was 66.00%,area under the curve(AUC)was 0.623,95%CI was 0.525-0.721,according to the judgment criteria,0.5<AUC<0.6,indicating low diagnostic value.7.No significant correlation was found between anti-ccp antibody and age,course of disease,number of tender joints,number of swollen joints,ESR,CRP,DAS28,and RF in RA-ILD patients.Conclusion1.The level of anti-cyclocitrullinated peptide(CCP)antibody in rheumatoid arthritis-associated interstitial lung disease(RA-ILD)was statistically significant compared with that of pure RA.The ROC curve of anti-ccp antibody in ra-ild was plotted,and the area under curve(AUC)was 0.623,between 0.5 and 0.7,which was considered to be of low diagnostic value according to the evaluation criteria.However,in this study,anti-CCP antibody level was significantly increased in patients with RA-ILD,and the difference of anti-CCP antibody between the two groups was statistically significant,suggesting that the high-titer anti-CCP antibody had certain predictive value for the onset of RA-ILD.2.RA-ILD patients with advanced age,long course of disease,high number of joint swelling and pain,high DAS28 score,high level of ESR,high level of CRP,high level of anti-CCP antibody are common.And age,DAS28 score,and anti-CCP antibody were independent risk factors for RA-ILD.