The Significance Of Anti-CCP And AKA Antibodies In The Differential Diagnosis Of PSS And SS-RA

Objective The present study aimed to investigate the expression of anti-cyclic citrullinated peptide antibodies(anti-CCP)/ anti keratin antibody(AKA) and analysis the correlations of anti-CCP and AKA with clinical manifestation and prognosis in patients with primary sjogren’s syndrome(p SS) and sjogren’s syndrome with rheumatoid arthritis(SS-RA), and to discuss the significance of anti-CCP and AKA in the differential diagnosis of p SS and SS-RA.Methods The general clinical data and laboratory data of 74 with sjogren’s syndrome(SS) were collected for analyzing the expression of anti-CCP and AKA in two groups of patients with p SS and SS- RA, and comparing their difference in RA diagnostic sensitivity with rheumatoid factor(RF). Analyzed the correlations of SS-RA with anti-CCP、AKA、RF and RF titter. Then the correlations of anti-CCP/AKA/RF/RF titter with xerophthalmia and xerostomia, joint symptoms, anti-SSA, anti-SSB, immunoglobulin G(Ig G), erythrocyte sedimentation rate(ESR), were performed by statistical analysis.Results Among 74 cases of patients, 61 patients were diagnosed with p SS, while 13 patients were diagnosed with SS-RA. The level of anti-CCP and AKA was detected in 52(70.3%) patients, 15 cases were positive for anti-CCP and AKA-positive were detected in 12 patients. Both anti-CCP-positive and AKA-positive were 12 cases while 11 of them were diagnosed with SS-RA; anti-CCP-positive and AKA-negative were 3 cases and only 1 was SS-RA. Otherwise, among 40 cases who with anti-CCP-negative and AKA-negative only 1 case was diagnosed with SS-RA. In p SS patients, the positive rate of anti-CCP and AKA was 7.69% and 2.56%. In SS-RA patients, the specificity of anti-CCP and AKA was 90.0% and 95.0%, while the sensitivity was 92.3% and 84.6%. The positive rates of Ig G in anti-CCP-positive and AKA-positive were lower than those in anti-CCP-negative and AKA-negative group, respectively. The rate of anti-CCP-positive was negatively associated with Ig G level(r=-0.313,P=0.027);similar result was found in the relation between AKA and Ig G level(r=-0.288,P=0.043). The positive rates of anti-SSB in anti-CCP-positive and AKA-positive were lower than those in anti-CCP-negative and AKA-negative group;RF was irrelevant to anti-CCP and AKA(P>0.05),while RF titter was related with AKA(r=0.314,P=0.025) but not anti-CCP( P=0.068).No significant relations were found among ESR、anti-SSA、RF 、ANA and anti-CCP/ AKA. Kaplan-Meier curve found that neither anti-CCP or AKA had significant association with xerostomia、xerophthalmia、joint symptoms. Univariate analysis revealed that both anti-CCP(r=0.809,P=0.000) and AKA(r=0.843,P=0.000)were positively correlated with SS-RA. Besides, RF titer also correrated with SS-RA(r=0.308,P=0.010).On the contrary, none of Ig G、ESR、anti-SSA、anti-SSB、Age、RF、Age had relation with SS-RA. Furthermore, we conducted two multivariate logistic regression models to make a multi-factor analysis which showed that only AKA associated with SS-RA.Conclusions:For p SS patients with articular symptoms and RF- positive, anti-CCP and AKA could be tested, witch can reduce the missed diagnosis of RA. Besides, joint detection of anti-CCP, AKA and RF titer not only can improve the sensitivity and specificity of diagnosis and also help in the early diagnosis of SS- RA.