| Objective To explore the serum level of anti-carbamylated protein(CarP)antibodies of RA-ILD patients and the early diagnosic value in RA-ILD.Methods From December 2017 to June 2019,clinical and laboratory data and serum samples of patients with RA in the General Hospital of Ningxia Medical University were collected.Patients were subclassified as RA-ILD and RA-without ILD based on computed tomography scans of the chest.Among them,129 patients in RA-ILD group and 57 patients in RA-without ILD group.Enzyme 1inked immunosorbent assay(ELISA)was used to assess anti-CarP antibody in the serum of each group.Mann-Whitney U test was used to compare the differences in anti-CarP antibody levels between the two groups,ROC curve was used to determine the best cut-off value for the diagnosis of RA-ILD,and Spearman correlation analysis was used to study the correlation between anti-CarP antibodies and other laboratory parameters.The laboratory test results of patients in each group were analyzed and compared,the single factor analysis was performed by t-test,U test and?~2 test,and significant variables were included in multivariate logistic regression analysis to obtain risk factors related to RA-ILD.Results1.Basic information of RA patients:a total of 186 patients with RA,male people were 36,and female people were 150,aged from 14-84 years old,average(53.77±13.16)years old;There were 57 patients with RA-without ILD group,7males and 50 females,aged from 14-77 years old,average(48.00±13.00)years old;tender joints were 10(3,17),swollen joints were 3(1,10),and 4 people(7.0%)were smokers;129 were in the RA-ILD group,males 29 and females 100,aged from 33-84 years old,average(60.00±10.00)years old,tender joints were 10(4,20),swollen joints were 4(1,12),and 14 people(11.0%)were smokers.2.Comparison of the basic situation between RA-ILD and RA-without ILD:the average age of RA-ILD group was(60.00±10.00)years old,higher than that in RA-without ILD group was(48.00±13.00)years old,and the difference was statistically significant(P<0.05).There was no significant difference in gender,smoking,course of disease,number of tender joints and number of swollen joints between the two groups(P>0.05).3.Comparison of serum anti-CarP antibody levels between RA-ILD and RA-without ILD:the level of anti-CarP antibody in RA-ILD group was 21.14(12.29,29.75)U/ml,higher than that in RA-without ILD 11.00(6.66,19.05)U/ml(P<0.05),and the difference was statistically significant(P<0.05);and the positive rate of anti-CarP antibody in RA-ILD group was higher than that in RA-without ILD group,and the difference was statistically significant(P<0.05).4.Comparison of anti-CarP levels in RA-ILD patients with gender,course of disease and AKA:further analysis showed that in RA-ILD,the anti-CarP antibody level in AKA-positive patients was higher than that in AKA-negative patients,and the difference was statistically significant(P<0.05),while the anti-CarP antibody level was not significantly different in differern sex and disease course group of RA-ILD patients(P>0.05).5.Comparison of laboratory parameters between RA-ILD and RA-without ILD:the CRP level was 24.25(4.16,45.7)mg/L in the RA-ILD group,higher than that in RA-without ILD was 8.99(1.61,27.9)mg/L,and the difference was statistically significant(P<0.05),the DAS28 was(5.7±1.2)in the RA-ILD group,higher than that in RA-without ILD was(5.0±1.3),and the t-test showed a significant difference between the two groups(P<0.05),there was no significant different in RF,anti-CCP antibody,ESR,IgA,IgG,IgM,C3,C4,and AKA levels between the two groups(P>0.05).6.Determine the cut-off value of anti-CarP antibodies in RA-ILD:the diagnostic efficacy was assessed by drawing the ROC curve,and the best cut-off value of anti-CarP antibody for RA-ILD was 20.56 U/mL,the specificity was84.20%,the sensitivity was 53.50%,the positive likelihood ratio was 3.41,and negative likelihood ratio was 0.55;Youden index was 0.377;the AUC was 0.76,and the 95%CI was 0.679-0.830,0.7<AUC<0.9 indicated moderate diagnostic accuracy,suggesting that anti-CarP antibody has value in the diagnosis of RA-ILD.7.Spearman correlation analysis in RA patients:Spearman correlation a-nalysis showed that anti-CarP antibody level was not associated with joint s welling number,joint tenderness number,DAS28 score,ESR,CRP,and anti-CCP antibody(P>0.05);and RF and age were positively correlated with anti-CarP(P<0.05)8.Risk factor analysis in patients with RA-ILD:univariate analysis sug-gested that age,DAS28,CRP,and anti-CarP antibody levels in the RA-ILD were higher than that in the RA-without ILD group,and the differences were statistically significant(P<0.05),while gender,smoking,course of disease,RF,anti-CCP antibody,ESR,IgA,IgG,IgM,C3,C4,and AKA levels were not statistically significant between the two groups(P>0.05).Multivariate analysi-s showed that anti-CarP antibody and age were independent risk factors for the development of RA-ILD(P<0.05).Conclusion1.The anti-CarP antibody level in RA-ILD patients is higher than that in RA-without ILD,suggesting that anti-CarP antibody may have diagnostic value in the development of RA-ILD.2.The anti-CarP antibody level ande age were independent risk factors for the development of RA-ILD... |
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