New biomarkers for rheumatoid arthritis

Rheumatoid factor (RF) has been commonly used as a biomarker of rheumatoid arthritis (RA). It is important to diagnose RA early and to prevent joint destruction before irreversible damage occurs. For this purpose, several new biomarkers, such as anti-cyclic citrullinated peptide antibody (anti-CCP) and matrix metalloproteinase-3 (MMP-3), have become available for both the diagnosis and prognosis of RA. RF showed a tolerable sensitivity of 68.5% for RA, but low specificity of 77.1% for patients with other rheumatic diseases. Anti-agalactosyl IgG antibodies (CARF) showed a slightly higher sensitivity of 73.9%, but specificity as low as that for RF. In contrast, anti-CCP demonstrated high sensitivity of 76.1% and marked specificity of 92.4% for patients with other rheumatic diseases. Anti-CCP was significantly superior to other biomarkers on receiver-operating characteristic curve (ROC) analysis. Moreover, meta-analysis revealed that the pooled sensitivity and specificity were 67% and 95% for anti-CCP, and 69% and 85% for RF, respectively, and that anti-CCP was more specific than RF for diagnosing RA. On the other hand, MMP-3 has been suggested to be a prognostic biomarker as well as an evaluative biomarker for RA. We next examined if the diagnostic accuracy of early RA is improved by combining these biomarkers. The specificity of RF was not as high as anti-CCP but rose to 92% when combined with MMP-3. Thus, we concluded that anti-CCP is superior to other biomarkers in terms of diagnostic accuracy, and that these combined assays are useful in the early diagnosis of RA.     

New diagnostic and evaluative tests for rheumatoid arthritis

To prevent joint destruction, it is important to diagnose RA early and to consider the prognosis. For this purpose, several new laboratory tests, such as IgG-RF, anti-agalactosyl IgG antibodies (CARF), and matrix metalloproteinase-3 (MMP-3), have become available for diagnosing RA. RF has a tolerable sensitivity of 68.5% for RA, but low specificity of 77.1%, and also 76.0% for patients with other rheumatic diseases and chronic inflammatory disease, respectively. CARF showed slightly higher sensitivity but low specificity for other rheumatic diseases and chronic inflammatory patients. In contrast, anti-cyclic citrullinated peptide antibody (anti-CCP), a new diagnostic test for RA, demonstrated significantly high specificity for other rheumatic diseases, and also for chronic inflammatory disease patients. Anti-CCP was superior to other laboratory tests by ROC analysis. Moreover, both CARF and anti-CCP had higher sensitivity of 66.7%, 61.5%, respectively, for the diagnosis of early RA than RF. On the other hand, MMP-3 is thought to be not only an evaluative test for the activity of RA because of its significant correlation with CRP, but also has potential as a prognostic test to identify joint damage from RA. Anti-CCP was also reported to associate with the progression of joint damage and may be also used as a prognostic test. We next examined the efficiency of RA diagnosis made by combining these laboratory tests. The specificity of RF was not as high as anti-CCP but reached 92% when combined with MMP-3. Thus, it is concluded that anti-CCP is superior to other laboratory tests in sensitivity and specificity, and that these combination assays are useful in the early diagnosis of RA.     

抗环瓜氨酸肽抗体检测对类风湿关节炎的临床诊断价值

目的探讨抗环瓜氨酸肽抗体（抗CCP抗体）检测对类风湿关节炎（RA）诊断的意义。方法采用酶联免疫吸附试验（ELISA）检测115份人血清的抗CCP抗体,同时采用免疫透射比浊法定量检测类风湿因子（RF）,包括40例RA患者,45例其它风湿病患者,30名正常人;并分析抗CCP抗体与RF实验结果之间的相关性。结果在40例RA病人中,抗CCP抗体的阳性率为80.0%,在其它风湿病人中的阳性率为7.0%,抗CCP抗体对RA的敏感性和特异性分别为80.0%、96.0%,其敏感性高于RF,但差异无统计学意义（P〉0.05）,特异性明显高于RF（P〈0.05）。联合应用抗CCP抗体与RF进行诊断,二者均阳性时敏感性为65.0%,特异性为97.3%。抗CCP抗体与RF实验结果之间无相关性。结论抗CCP抗体对RA具有较好的敏感性和很高的特异性,可与RF相互补充,联合检测可提高对RA早期诊断的准确性。     

Topics on immunological tests for rheumatoid arthritis

To prevent joint destruction, it is important to diagnose RA early and to speculate the prognosis. Several new laboratory tests have been developed for this purpose. In addition to rheumatoid factor (RF), IgG-RF, anti-agalactosyl IgG antibodies (CARF), and matrix metalloproteinase 3 (MMP-3) have become available as diagnostic tests for RA. Among them, anti-cyclic citrullinated peptide antibodies (anti-CCP antibodies) have the sensitivity and specificity of 81.0% and 92.4%, respectively, which are superior to other laboratory tests by ROC analysis. Moreover, the specificity of anti-CCP antibodies to diagnose early RA was much higher than that of RF, although the sensitivity of CARF was slightly high compared with that of RF. In contrast, MMP-3 is thought to be an evaluative test for the activity of RA because a significant correlation was found between MMP-3 and CRP, but MMP-3 has a possibility as a prognostic test to know the joint damage of RA. We have shown that the progression of joint damage (Sharp score) was faster in MMP-3-positive patients than negative patients. Anti-CCP antibodies was also reported to associate with the progression of joint damage and may be used also as a prognostic test. We next examined how efficiently was the diagnosis of RA made by combining these laboratory tests. Although anti-CCP antibodies are highly specific to RA, the specificity of RF was not so high but became up to 92% when combined with MMP-3. In order to diagnose RA efficiently, we may firstly examine RF, next MMP-3 if RF is positive, and anti-CCP antibodies if RF is negative.     

RF、AKA和抗CCP抗体联检对类风湿关节炎诊断的临床价值

目的:探讨类风湿因子(Rheum atoid factor,RF)、抗角质蛋白抗体(antikeratin antibody,AKA)及抗环瓜氨酸肽(anti-cyc lic c itru llinated peptide,CCP)抗体对类风湿关节炎(rheum atoid arthritis,RA)的临床意义和早期应用价值。方法:对40例类风湿关节炎患者、30例系统性红斑狼疮和30名正常健康体检者进行RF、AKA、抗CCP抗体检测,应用速率散射比浊法测定RF,间接免疫荧光法检测AKA,ELISA法测定抗CCP抗体。结果:40例RA患者血清中,RF灵敏度和特异性分别为70.0%、90.0%,AKA灵敏度和特异性分别为35.0%、96.7%,抗CCP抗体灵敏度和特异性分别为85.0%、93.3%,联检RF、AKA及抗CCP抗体灵敏度和特异性分别为97.07%、99.8%。结论:RF、AKA和抗CCP抗体可作为诊断RA比较特异的血清学指标,三项指标联检可在一定程度上弥补RF对RA的诊断不足,提高RA的阳性诊断率,且有助于疾病的预后判断。     

New diagnostic tests for rheumatoid arthritis

Rheumatoid factor(RF) is one item in the classification criteria for rheumatoid arthritis(RA), with a tolerable sensitivity of 69.3% for RA but low specificity against other rheumatic diseases(76.4%). Anti-agalactosyl IgG antibody(CARF) showed a slightly higher sensitivity(72.0%) but the specificity was even lower(67.9%). Anti-cyclic citrullinated peptide antibody(anti-CCP), a new diagnostic test for RA, demonstrated higher sensitivity(76.0%) and specificity(91.5%), and the ROC analysis revealed the marked superiority of anti-CCP to other markers(i.e. RF, CARF, and IgG-RF). Matrix metalloproteinase-3 (MMP-3) showed a significantly positive correlation with CRP, suggesting it might be more useful for evaluation of RA activity and prediction of the prognosis of joint destruction. On the contrary, two combination assays, "MMP-3 or CARF" and "MMP-3 or anti-CCP", showed the highest sensitivity(86.7%) for RA. Similarly, in early RA the sensitivities of CARF, MMP-3 and anti-CCP were lower than in RA(66.7%, 66.7% and 58.3%, respectively), but the sensitivities of combination assays "MMP-3 or CARF" and "MMP-3 or anti-CCP" were 91.7% and 83.3%, respectively. Thus, we concluded that these combination assays are useful in the diagnosis of RA and detection of early RA.     

Diagnostic performances of anti-cyclic citrullinated peptides antibody and antifilaggrin antibody in Korean patients with rheumatoid arthritis

Rheumatoid arthritis (RA) is a systemic autoimmune disease of unknown etiology. We studied the diagnostic performances of anti-cyclic citrullinated peptides antibody (anti-CCP) assay and recombinant anti-citrullinated filaggrin antibody (AFA) assay by enzyme linked immunosorbent assay (ELISA) in patients with RA in Korea. Diagnostic performances of the anti-CCP assay and AFA assay were compared with that of rheumatoid factor (RF) latex fixation test. RF, anti-CCP, and AFA assays were performed in 324 RA patients, 251 control patients, and 286 healthy subjects. The optimal cut off values of each assay were determined at the maximal point of area under the curve by receiver-operator characteristics (ROC) curve. Sensitivity (72.8%) and specificity (92.0%) of anti-CCP were better than those of AFA (70.3%, 70.5%), respectively. The diagnostic performance of RF showed a sensitivity of 80.6% and a specificity of 78.5%. Anti-CCP and AFA showed positivity in 23.8% and 17.3% of seronegative RA patients, respectively. In conclusion, we consider that anti-CCP could be very useful serological assay for the diagnosis of RA, because anti-CCP revealed higher diagnostic specificity than RF and AFA at the optimal cut off values and could be performed by easy, convenient ELISA method.     

类风湿因子及相关自身抗体对类风湿关节炎的诊断价值

目的探讨类风湿因子（RF）、抗环瓜氨酸肽抗体（抗CCP）及抗角蛋白抗体（AKA）联合检测对类风湿关节炎（RA）的临床诊断价值。方法对80例RA和65例非RA的其他自身免疫病患者检测RF、RF-IgM、抗CCP及AKA 4种指标。结果自身免疫性疾病女性发病较高,以RA组为甚;RA组的RF、RF-IgM、抗CCP及AKA高于其他自身免疫性疾病组;单指标检测RA诊断的敏感性为RF〉RF-IgM〉AKA〉抗CCP,特异性为RF-IgM〉抗CCP〉RF〉AKA。阳性预测值为抗CCP〉RF〉RF-IgM、AKA,阴性预测值为RF〉RF-IgM〉AKA〉抗CCP;以并联或串联方式联合检测均以RF、RF-IgM及抗CCP三联及RF、RF-IgM、抗CCP及AKA四联检测为佳,并联检测的敏感性分别为93%及97%,串联检测的特异性分别为98%及99%。结论 RF、RF-IgM、抗CCP及AKA 4种指标联合检测可提高对RA诊断的敏感性和特异性,对RA的早期诊断有较高价值。     

抗CCP抗体和AKA在类风湿关节炎诊断的应用价值

目的 比较抗环瓜氨酸肽抗体(抗CCP抗体)和抗角蛋白抗体(AKA)在类风湿关节炎诊断中作用,探讨RA的早期诊断方法.方法 对已确诊的85例RA患者、74例非RA的自身免疫病患者同时测定抗CCP抗体(ELISA法)、AKA(间接免疫荧光检测).结果 抗CCP抗体对诊断RA的灵敏度和特异性分别为75.3％和93.2％;AKA对RA诊断的灵敏度和特异性分别为89.4％和85.14％.抗CCP抗体的灵敏度与AKA灵敏度差异无统计学意义(P＞0.05),特异性差异有统计学意义(P＜0.05);抗CCP抗体或AKA与二者联合检测的灵敏度差异有统计学意义(P＜0.05),特异性差异有统计学意义(P＜0.05).阳性预测值抗CCP抗体较高,阴性预测值以二者联合检测较好,Youden index二者联合检测比单独检测抗CCP抗体或AKA高.抗CCP抗体和AKA在检测RA组中抗CCP抗体和AKA同时阳性检出58例;抗CCP抗体或AKA阳性共检出85例.抗CCP抗体或AKA阳性率(96.5％)比二者同时阳性率(68.2％)大大提高.结论 抗CCP抗体、AKA对RA具有较好的灵敏度和高度的特异性,联合检测抗CCP抗体和AKA可作为早期RA患者及RF阴性RA患者的早期诊断指标.     

Autoantibodies in Patients with Rheumatoid Arthritis

Aim:  The aim of this study is to examine the diagnostic value of autoanitbodies in patients suffering from rheumatoid arthritis. We evaluated the presence of the following autoantibodies: rheumatoid factor (RF), antinuclear antibodies (ANAs), antibodies against cadiolipin (a-CL) and antibodies against cyclic citrullinated peptide (anti-CCP).
Methods:  We studied the presence of RF, ANA, a-CL and anti-CCP in 40 patients with rheumatoid arthritis. Rheumatoid factor was measured using nephelometric method, while ANAs were examined by indirect immunofluorescence technique using Hep-2 cells as substrate. Sera that reacted at 1/80 dilution were classified as ANA positive. Positive sera were studied up to 1/1280 dilution. A-CL and anti-CCP were measured by enzyme-linked immunosorbent assay.
Results:  RF was positive in 30 patients (75%), ANA in 15 (37%), a-CL in 10 (25%) and anti-CCP in 36 (90%). Predominant pattern of nuclear staining of ANA-positive sera was homogenous and speckled type. ANA titres were particularly low; most patients (6) had ANA titre equal to 1/80, and five patients had a titre of 1/160, while only four out of 40 had an ANA titre of 1/320.
Conclusions:  Autoimmune disorders such as RA are characterized by various autoantibodies that usually are not specific, as they are present in many other diseases. However, RF and especially anti-CCP are very often and show higher specificity for RA, being useful diagnostic serological markers. On the other hand, ANA and a-CL are less common in RA paitents; they may be useful in terms of prognosis and treatment, but they always should be evaluated in correlation with the clinical features and the rest of the laboratory findings of each patient.     

抗-CCP抗体、RF与CRP联合检测对类风湿性关节炎早期诊断研究

目的探讨抗环瓜氨酸多肽（抗-CCP）抗体、类风湿因子（RF）与C-反应蛋白（CRP）联合检测在类风湿性关节炎（RA）中的诊断价值。方法采用半定量酶联免疫吸附法和定量免疫散色比浊法分别检测两组人群血清中的抗一CCP抗体、RF与C一反应蛋白（CRP）浓度,并分析上述三指标与RA的相关性。结果抗-CCP抗体诊断RA的特异度为93．5％,灵敏度为72．6％,RF为77．3％和83．4％,CRP为63．6％和82．3％,三者诊断灵敏度和特异度分别高达92．5％和97．6Voo。结论抗-CCP抗体诊断RA的特异度最高,RF的灵敏度最高,而三者联合早期诊断RA效率最好,与单一诊断指标相比具有明显的统计学意义。     

The diagnostic utility of anti-cyclic citrullinated peptide antibodies, matrix metalloproteinase-3, rheumatoid factor, erythrocyte sedimentation rate, and C-reactive protein in patients with erosive and non-erosive rheumatoid arthritis

OBJECTIVE: To compare the diagnostic utility of laboratory variables, including matrix metalloproteinase-3 (MMP-3), anticyclic citrullinated peptide (CCP) antibodies, rheumatoid factor (RF), erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP) in patients with erosive and non-erosive rheumatoid arthritis (RA). METHODS: We assembled a training set, consisting of 60 patients with RA, all fulfilling the revised criteria of the American College of Rheumatology. A commercial enzyme linked immunosorbent assay (ELISA) was used both to test for anti-CCP antibodies (second generation ELISA kit) and MMP; RF were detected by latex-enhanced immunonephelometric assay. CRP was measured by latex turbidimetric immunoassay. RESULTS: The levels of anti-CCP antibody titers and ESR were significantly higher in patients with erosive disease than those in non-erosive RA patients (p < 0.001 and 0.0341) respectively. Moreover, a higher frequency of elevated titers of anti-CCP antibodies was found in RA patients with erosions compared to patients with non-erosive RA (78.3% vs. 43.2% respectively). The ROC curves of anti-CCP passed closer to the upper left corner than those other markers and area under the curve (AUC) of anti-CCP was significantly larger than AUC of other markers (0.755 for anti-CCP, 0.660 for ESR, 0.611 for CRP, 0.577 for RF, and 0.484 for MMP-3 female). A positive predictive value was higher for anti-CCP antibodies in comparison to other markers. We did not find significant statistical correlation between anti-CCP antibody titers and inflammatory markers such as ESR or CRP. However, we confirmed the correlation of elevated titers of anti-CCP antibodies and RF in both groups of patients whereas the degree of correlation was more significant in non-erosive patients. CONCLUSION: The results of our study suggest that the presence of elevated anti-CCP antibody titers have better diagnostic performance than MMP-3, RF, CRP and ESR in patients with erosive RA.     

Autoantibodies recognizing citrullinated rat filaggrin in an ELISA using citrullinated and non-citrullinated recombinant proteins as antigens are highly diagnostic for rheumatoid arthritis

The objective of the study was to determine the diagnostic value for rheumatoid arthritis (RA) of anti-filaggrin autoantibodies (autoAb) recognizing citrullinated recombinant rat filaggrin (ACRF) in community cases of very early arthritis. To evaluate the diagnostic value of ACRF, were studied sera from patients with different classified rheumatic diseases and healthy subjects (group 1, n= 422) and 314 community cases of very early arthritis (group 2) that were classified as RA (n = 176), non-RA (n = 63) and undifferentiated (n = 75) arthritides after 1 years of follow-up. ACRF were measured using a new ELISA, with results expressed as the difference between the OD value obtained on citrullinated minus that on noncitrullinated rat filaggrin (differential ACRF; dACRF). For both groups, rheumatoid factors (RF), anti-keratin autoAb (AKA) and anti-perinuclear factor (APF) were tested; for group 2, anti-CCP autoAb were also tested. Different reactivity patterns against citrullinated and noncitrullinated filaggrin were observed. Almost all sera reacting with citrullinated but not noncitrullinated filaggrin were from RA patients. Among RA and non-RA sera that recognized both forms of filaggrin, a positive result was obtained only with RA sera. For groups 1 and 2, dACRF sensitivity was 58.4% and 30.7%, and specificity for RA was 99.5% and 98.4%, respectively. In group 2, dACRF specificity for RA was better than that of RF (92.1%), APF (95.2%), AKA (96.8%) and anti-CCP (95.2%). dACRF positive predictive value was high (98.2) and close to that given by the concomitant positivity of RF and anti-CCP autoAb. Despite a high positive correlation between AKA, APF, anti-CCP and dACRF test results, they were complementary since some sera were positive for only one test. Thus, in a community setting, anti-citrullinated rat filaggrin reactivity detected by a new ELISA, whose originality is based on the difference between serum's reactivities on the citrullinated and native forms of filaggrin, had a higher diagnostic value for RA than other autoAb.     

类风湿关节炎四种自身抗体的检测及意义

为评估类风湿因子(rheumatoid factor,RF)、抗环瓜氨酸肽(cyclic citrullinated pepdide,CCP)抗体、抗Sa抗体和抗角蛋白抗体(anti-keratin antibody,AKA)自身抗体对类风湿关节炎(rheumatoid arthritis,RA)诊断的意义,采用速率散...     

抗环瓜氨酸肽抗体、葡萄糖6-磷酸异构酶及类风湿因子的检测及对类风湿关节炎的诊断价值

目的为寻找敏感性高、特异性强的诊断类风湿关节炎(RA)的实验指标,选择抗环瓜氨酸肽(CCP)抗体、葡萄糖6-磷酸异构酶(GPI)和类风湿因子(RF)并探讨对RA的诊断价值。方法抗CCP抗体和GPI试验采用酶联免疫吸附(ELISA)法,RF用胶乳凝集法,检测了125例RA患者(RA组)、56例其他风湿性疾病患者(对照组)和36例健康体检者(正常组)血清中上述3者的浓度。结果抗CCP抗体、GPI及RF,在RA组分别是:(83.6±45.9)RU/ml、(2.8±2.3)μg/ml和(320.4±208.6)IU/ml;在对照组分别是:(36.2±15.3)RU/ml、(0.19±0.06)μg/ml和(36.3±12.5)IU/ml;在正常组分别是:(19.2±8.6)RU/ml、(0.16±0.08)μg/ml和(19.2±6.5)IU/ml。在RA组中,3者的敏感度分别是64.8%、73.6%和69.6%,特异性分别是92.0%、72.8%和74.4%。结论 RA患者血清抗CCP抗体、GPI和RF显著高于其他疾病患者(P<0.01)。抗CCP抗体和GPI有可能成为诊断RA的新指标、RA的血清标志物,对提高诊断RA的敏感性和特异性,具有良好的临床研究和推广价值。     

Diagnostic value of anti-mutated citrullinated vimentin in comparison to anti-cyclic citrullinated peptide and anti-viral citrullinated peptide 2 antibodies in rheumatoid arthritis: An Italian multicentric study and review of the literature

In the last years, the detection of antibodies (Abs) against citrullinated peptides (ACPA) has largely replaced rheumatoid factor (RF) as the most helpful biomarker in the diagnosis of rheumatoid arthritis (RA). Current assays detect ACPA reactivity with epitopes on various different citrullinated proteins. Among these, anti-cyclic citrullinated peptide (CCP) Abs have been widely demonstrated to be an important diagnostic and prognostic tool because of their high specificity. Recently, citrullinated vimentin, a protein highly released in synovial microenvironment, has been identified as potential autoantigen in the pathophysiology of RA and an enzyme-linked immunosorbent assay (ELISA) for the detection of Abs directed against a mutated citrullinated vimentin (anti-MCV) was developed. Several recent studies evaluating the characteristics of anti-MCV in comparison to anti-CCP Abs, have given conflicting results. Anti-MCV have been demonstrated to perform better than anti-CCP as predictor of radiographic damage. Conversely, its additional diagnostic and prognostic role in comparison to anti-CCP in both early and established RA is controversial. Aim of this study was to evaluate the diagnostic performance of anti-MCV in RA and to compare it to anti-CCP and the recently developed assay targeting viral citrullinated peptide 2 (VCP2) in a large cohort of RA patients (n=285), healthy subjects and other disease controls (n=227). Anti-MCV resulted to have a sensitivity of 59% and a specificity of 92%. In comparison, anti-CCP and anti-VCP2 displayed a sensitivity of 77% and 61% and a specificity of 96% and 95%, respectively. Of interest, at the manufacturer recommended cutoff value of 20U/mL, a high percentage of healthy subjects as well as Epstein Barr (EBV) and hepatitis C (HCV) virus infected patients resulted anti-MCV positive. In our large cohort of RA patients, anti-MCV demonstrated lower sensitivity than anti-CCP and VCP2 test, thus not allowing to confirm previously published data. Moreover, the high rate of detection in infectious diseases limits its diagnostic value in undifferentiated arthritis.     

A new strategy for the early diagnosis of rheumatoid arthritis: a combined approach

Rheumatoid arthritis [RA] is one of the most common and severe autoimmune rheumatic diseases, diagnosed primarily according to clinical manifestations and radiological reports. For many years, laboratory diagnosis of rheumatoid arthritis has relied on the detection of rheumatoid factor [RF], as established by the ACR criteria. A recent test to detect antibodies towards citrullinated peptides, called the anti-CCP assay, showed a similar sensitivity but a more elevated specificity than the RF test. Our intention was the recognition of an optimal diagnostic strategy that exhibits the highest sensitivity and specificity for RA detection. To this purpose, we examine the usefulness of autoantibodies in RA testing, evaluating the diagnostic performance of conventional and innovative assays for RF detection, and ELISA anti-CCP test, for anti-CCP antibodies detection, by a prospective study. Multiplex cytofluorimetric test appeared to be more sensitive and specific than nephelometric assay for RF detection. Hence, a novel combined approach, significantly increasing the diagnostic sensitivity for RA, was planned, employing the multiplex RF test in combination with the anti-CCP test.     

抗CCP抗体与RF联合检测在类风湿关节炎早期诊断中的意义

目的 探究抗CCP抗体与RF联合检测在类风湿关节炎早期诊断中的意义。方法 选取2017年11月~2018年11月我院收治的30例类风湿关节炎患者设为研究组,另选取同期进行健康体检者30例设为对照组,对两组进行抗CCP抗体与RF联合检测,并且分析抗CCP抗体、RF单独及两者联合检测的敏感性、特异性、阳性预测值和阴性预测值。结果 研究组抗CCP抗体阳性率96.67%、RF阳性率93.33%和两者联合检测阳性率86.67%均高于对照组的6.67%、3.33%及3.33%;研究组抗CCP抗体水平（78.65±14.33）U/ml和RF水平（314.22±20.56）IU/ml均高于对照组的（2.69±2.14）U/ml和（10.01±3.54）IU/ml（P＜0.05）。结论 对类风湿关节炎患者抗CCP抗体与RF的诊断敏感度拥有着一定的相似性,但抗CCP抗体特异度高于RF的特异度,若两者联合检测可极大提高敏感度,对于类风湿关节炎患者早期诊断工作的开展拥有着积极的推动作用。     

抗CCP抗体和RF联检在RA诊疗中的临床价值

目的：研究抗环瓜氨酸肽（anti-cyclic citrullinated peptide,Anti-CCP）（抗CCP抗体）和RF的检测在类风湿关节炎（RA）诊疗中的临床价值。方法：分别用酶联免疫吸附试验（ELISA）、BeckMan全自动蛋白分析仪同时检测早期RA组（病程〈1年）42例,RA组（病程〉1年）40例,非RA对照组40例患者血清抗CCP抗体和RF。结果：早期RA组、RA组的抗CCP抗体、RF阳性率显著高于非RA对照组（P〈0.05）RA组抗CCP水平显著高于早期RA组（P〈0.01）,两者RF无显著差别（P〉0.05）。RA组与早期RA组CCP抗体与RF二者无相关性。结论：联检抗CCP抗体、RF有助于类风湿的早期诊断和预测病情的进展。     

Prevalence of Autoantibodies to Cyclic Citrullinated Peptide in Patients with Rheumatic Diseases other than Rheumatoid Arthritis: A French Multicenter Study

Our objective was to evaluate the prevalence of autoantibodies to cyclic citrullinated peptides (anti-CCP aAbs) in a cohort of patients with a variety of inflammatory or non-inflammatory rheumatic diseases other than rheumatoid arthritis (RA). Six hundred and nine serum samples were tested for anti-CCP aAbs and for rheumatoid factor (RF) using enzyme-linked immunosorbent assays and immunonephelometry. The prevalence of anti-CCP aAbs and RF reached 10% and 25%, respectively, using the positive cutoff value suggested by the manufacturers. Using a higher cutoff value (50 U/ml) for both aAbs, the prevalence was lower with 6% and 16%, respectively. The specificity of both markers for RA thus reached 94% and 84%, respectively. Anti-CCP aAbs were found to be elevated in inflammatory and also in non-inflammatory rheumatic diseases in the same proportion. Clinical data obtained for 36 positive patients showed that 17% developed RA within 5 years. In conclusion, anti-CCP aAbs are clearly more specific than RF for RA. Follow-up of anti-CCP aAbs-positive patients with inflammatory or non-inflammatory rheumatic diseases other than RA could be important considering the predictive value of these aAbs for the development of RA.