anti-CCP Negative Patients Research Articles

Performance of Anti-Carbamylated Protein Antibody Testing in the Routine Evaluation of Rheumatoid Arthritis from a Single Center.

Detection of anticyclic citrullinated peptide antibodies (anti-CCP) and rheumatoid factors (RF) in sera support the diagnosis of rheumatoid arthritis (RA); however, these markers are not detected in about 20% of RA patients. More recently, antibodies against carbamylated proteins (anti-CarP) have emerged with implications for preclinical RA diagnosis. The objective of this study was to assess the clinical performance of anti-CarP and correlate with disease severity in routine clinical practice. Retrospective chart review of 331 subjects submitted for RA panel serology: 136 clinically defined RA-positive and 195 RA-negative patients. Fifty additional individuals were recruited for healthy controls. Patients' sera were tested for anti-CCP, anti-CarP, and RF antibodies. Clinical performance characteristics were evaluated for anti-CarP individually and in combination with anti-CCP and RF. Documented erosions and synovitis were correlated with anti-CarP positivity. Anti-CarP had a clinical sensitivity and specificity of 27% and 94%, respectively, for established RA. This sensitivity was lower than anti-CCP (79%) and RF (85%). The specificity of anti-CarP was similar to anti-CCP (93%) and higher than RF (69%). Anti-CarP in combination with anti-CCP and RF increased specificity (100%) but decreased sensitivity (21%). There was no correlation of anti-CarP positivity with presence of bone erosions; however, there was an increase in anti-CarP positivity among patients with synovitis. Anti-CarP demonstrates high specificity in diagnosis of established RA but lacks clinical sensitivity. In combination, anti-CarP does not improve clinical performance of anti-CCP and RF but may be useful in anti-CCP negative patients and in identifying patients with more active disease.

Factors influencing the SARS-CoV-2 infection and vaccination induced immune response in rheumatoid arthritis.

BackgroundTo investigate the factors that have significant impact on the Severe Acute Respiratory Syndrome Corona Virus 2 (SARS-CoV-2) infection and vaccination induced immune response in rheumatoid arthritis (RA).MethodsSerological response was measured by quantifying anti-SARS-CoV-2 specific antibodies, while the cell-mediated response was measured by a whole-blood test quantifying the interferon (IFN)-γ response to different SARS-CoV-2-specific domains.ResultsWe prospectively enrolled 109 RA patients and 43 healthy controls. The median time (IQR) between the confirmed infection or the last vaccination dose and the day when samples were taken (“sampling interval”) was 3.67 (2.03, 5.50) months in the RA group. Anti-Spike (anti-S) specific antibodies were detected in 94% of RA patients. Among the investigated patient related variables, age (p<0.004), sampling interval (p<0.001), the brand of the vaccine (p<0.001) and targeted RA therapy (TNF-inhibitor, IL-6 inhibitor, anti-CD20 therapy) had significant effect on the anti-S levels. After covariate adjustment TNF-inhibitor therapy decreased the anti-S antibody concentrations by 80% (p<0.001). The same figures for IL-6 inhibitor and anti-CD20 therapy were 74% (p=0.049) and 97% (p=0.002), respectively. Compared to subjects who were infected but were not vaccinated, the RNA COVID-19 vaccines increased the anti-S antibody levels to 71.1 (mRNA-1273) and 36.0 (BNT162b2) fold (p<0.001). The corresponding figure for the ChAdOx1s vaccine is 18.1(p=0.037). Anti-CCP (anti-cyclic citrullinated peptides) positive patients had 6.28 times (p= 0.00165) higher anti-S levels, than the anti-CCP negative patients. Positive T-cell response was observed in 87% of the healthy volunteer group and in 52% of the RA patient group. Following vaccination or infection it declined significantly (p= 0.044) but more slowly than that of anti-S titer (6%/month versus 25%). Specific T-cell responses were decreased by 65% in patients treated with anti-CD20 therapy (p=0.055).ConclusionOur study showed that the SARS-CoV-2-specific antibody levels were substantially reduced in RA patients treated with TNF-α-inhibitors (N=51) and IL-6-inhibitor (N=15). In addition, anti-CD20 therapy (N=4) inhibited both SARS-CoV-2-induced humoral and cellular immune responses. Furthermore, the magnitude of humoral and cellular immune response was dependent on the age and decreased over time. The RNA vaccines and ChAdOx1s vaccine effectively increased the level of anti-S antibodies.

Citrullinated Antigens with Multiple Citrulline Similar Motif in the Diagnosis of Rheumatoid Arthritis: A Preliminary Single-Center Study

The presence of anti-citrullinated protein antibodies (ACPAs) in the serum is one of the immunological features of rheumatoid arthritis (RA). Anti-cyclic citrullinated peptide (CCP) assay has been widely used in clinic for the diagnosis of RA. However, up to 40% of RA patients are anti-CCP negative and the diagnostic sensitivity in this population needs to be improved for better clinical management. In this study, peptides with Multiple Citrulline Similar Motif (MCSM) were synthesized and a new ELISA system, which we called RA_CP, was developed to detect citrullinated antigens with MCSM present in the serum. 106 RA,48 other arthritis patients and 41 sex- and age-matched healthy controls (HCs) were included in this study. Patients with RA have a significantly higher amount of citrullinated antigens with MCSM than other arthritis patients and HCs. RA patients with positive anti-CCP are also MCSM positive, whereas 75% anti-CCP negative patients are positive for MCSM. The diagnostic sensitivity for anti-CCP and MCSM was 81.1% and 95.3%, while the specificity was 100% and 94.4%, respectively. ROC curve analyses showed that the area under the curve (AUC) values were 0.906 (95% CI: 0.860-0.951) for anti-CCP and 0.948 (95% CI: 0.912-0.985) for MCSM while the combination of MCSM and anti-CCP test has the highest AUC (0.971, 95% CI: 0.946–0.996). Our results suggest that detection of citrullinated antigens with MCSM has improved sensitivity compared with anti-CCP assay and could serve as a biomarker in diagnosis of RA patients.

Antibody to peptidoglycan recognition protein (PGLYRP)-2 as a novel biomarker in rheumatoid arthritis.

To identify novel autoantigens from circulating immune complexes (CICs) in rheumatoid arthritis (RA) patients and further explore their clinical significance. From serum samples of 10 early RA (ERA) patients and 10 healthy donors, CICs were isolated and subjected to orbitrap mass spectrometry for autoantigen identification. Antibodies against the peptidoglycan recognition protein-2 (PGLYRP-2) derived from CICs were further detected by indirect enzyme-linked immunosorbent assay (ELISA) in 178 patients with RA, compared with 59 osteoarthritis (OA), 59 systemic lupus erythematosus (SLE), 55 ankylosing spondylitis (AS), 95 primary Sjögren's syndrome (pSS) and 50 healthy controls (HC). Thirty-three potential antigens out of 323 proteins were identified from CICs of RA patients. The autoantibodies to PGLYRP-2 were significantly increased in RA patients with 42.70% sensitivity and 85.20% specificity in comparison to other rheumatic diseases and healthy controls. The prevalence of anti-PGLYRP-2 was also elevated in subgroups of RA, with 34.72% in ERA, 35.29% in RF negative and 42.86% in anti-CCP negative patients. Further analysis suggested that anti-PGLYRP-2 was potentially accompanied with production of other autoantibodies in RA. In addition, we found by homology analysis that an epitope of PGLYRP-2442-447 mimics amino acid residues 431-436 of N-acetylmuramoyl-L-alanine amidase (NAMLAA) in actinomyces naeslundii. Autoantibody against PGLYRP-2 was identified as a promising biomarker in RA, especially in early and seronegative patients.

Assessment of serum levels of anti‑cyclic citrullinated peptide antibodies in patients with psoriatic arthritis: A cross‑sectional study in a Brazilian cohort

Presence of the anti-cyclic citrullinated peptide (CCP) antibody is considered a hallmark of rheumatoid arthritis, and may be found in patients with other rheumatic diseases, including psoriatic arthritis (PsA). The aim of the present study was to determine whether the anti-CCP antibody was present in patients with psoriasis with and without arthritis. and to determine whether its presence was associated with clinical, serological and treatment data in patients with PsA. The present study was a cross-sectional study, which included 91 patients with psoriasis (41 with arthritis and 48 without arthritis) as well as an age and sex matched control group consisting of 100 healthy individuals. Presence of the anti-CCP antibody was determined using commercially available ELISA kits. Data on clinical, serological and treatment characteristics was obtained from reviewing each patient's medical history. The quality of life and articular inflammatory activity were assessed using the Short Form Health Survey-12 questionnaire. Skin disease was evaluated using the Psoriasis Area Severity Index and body surface area. In the control group, 1% of individuals were positive for the anti-CCP antibody, whereas 17.5% of the psoriasis patients were positive (P<0.001). In the patients with PsA, 20.9% were positive for the antibody, and in patients with psoriasis without joint disease, 14.5% were positive (P=0.58). Patients with polyarticular forms of PsA were more likely to be anti-CCP positive compared with patients with skin disease without arthritis (P=0.009). In the group of patients with PsA, those who were anti-CCP positive were more likely to suffer from polyarticular forms of arthritis, but no differences were found in the quality of life, joint disease activity, degree of skin involvement and treatment requirements (all P>0.05). In conclusion, 17.5% of patients with psoriasis and 20.9% of patients with PsA were positive for anti-CCP antibodies. Polyarticular arthritis was more common in the anti-CCP positive patients compared with the anti-CCP negative patients.

Diagnostic value and clinical significance of anti-carbamylated protein (anti-CarP) antibodies in Egyptian patients with rheumatoid arthritis

Aim of the workThe study was performed to assess the diagnostic potential of anti-carbamylated proteins (anti-CarP) antibodies in Egyptian patients with RA and their relation to clinical manifestations, laboratory findings and radiological damage. Patients and methodsThe study involved 90 RA patients and 90 matched healthy controls. Disease activity score (DAS28) and health assessment questionnaire (HAQ) were assessed. Plain x-ray hands and feet were performed and assessed by modified Larsen’s score. Laboratory investigations including acute phase reactants, rheumatoid factor (RF), anti-cyclic citrullinated peptide (anti-CCP) and anti-CarP antibodies were estimated. ResultsThe patients mean age was 42.6 ± 10.4 years (20–60 years), disease duration was 4.3 ± 3.3 years and were 82 females (91.1%) and 8 males (8.9%). The mean DAS28 was 4.9 ± 1.2, HAQ was 1.6 ± 0.7 and Larsen score 33.8 ± 12.2. 29/90 (32.2%) patients were positive for anti-CarP antibodies and were significantly associated with extra-articular manifestations and deformity (p < 0.001), but not with acute phase reactants. Anti-CarP antibodies significantly associated with modified Larsen’s (p < 0.001), but not DAS28 (p = 0.13). The sensitivity and specificity were 32.2% and 96.7% for anti-CarP antibodies, 61.1% and 97.8% for anti-CCP antibodies, 66.7% and 91.1% for RF respectively. 25.7% of anti-CCP negative patients showed anti-CarP positivity, and radiological damage was significantly associated with anti-CarP in them. ConclusionThe sensitivity of anti-CarP antibodies was low in comparison to both RF and anti-CCP; however, they showed high specificity and were detected in anti-CCP negative patients, so they could be useful to test beside anti-CCP and RF. Anti-CarP antibodies may reflect disease radiological damage.

Genetic variant of IL-10RA and susceptibility to rheumatoid arthritis in a Chinese population.

The aim of this study was to investigate the relationship between the single-nucleotide polymorphisms (SNPs) of interleukin 10 alpha receptor (IL10RA) gene and rheumatoid arthritis (RA) in a Chinese population. We examined 533 RA patients and 958 subjects as a control group. Three IL-10RA SNPs (rs9610, rs2229113 and rs3135932) were genotyped using TaqMan genotyping assays on Fluidigm 192.24 system. The IL-10RA rs9610 A allele was increased in patient group compared with control subjects (OR=1.232, 95% CI=1.052-1.442, p=0.030). Significant difference in genotype distribution was found in RA patients and controls (χ2=15.32, p<0.001). We also discovered a statistical significance under the dominant model (GG+AG versus AA: OR=0.676, 95% CI=0.546-0.837, p<0.001). However, no significant difference was discovered in the recessive model (GG versus AG+AA: OR=1.013, 95% CI=0.754-1.361, p=0.932). Interestingly, significant differences were detected both in the allele and genotype frequencies of rs9610 between anti-CCP positive patients and anti-CCP negative patients (χ2=7.209, p=0.007; χ2=9.061, p=0.011; respectively). We also found a significant difference in genotype frequency at rs9610 in females compared with males (χ2=7.658, p=0.022). Unfortunately, we failed to find any significant results between two IL-10RA SNPs (rs2229113 and rs3135932) and RA susceptibility. The findings suggest that IL-10RA rs9610 polymorphism might contribute to RA susceptibility.

Independence of carbohydrate-deficient isoforms of transferrin and cyclic citrullinated peptides in rheumatoid arthritis

ObjectiveThe aim of this study was to assess the relationship between the two types of posttranslational modifications of proteins in RA: glycosylation on the example of carbohydrate-deficient transferrin and citrullination by means of autoantibodies to cyclic citrullinated peptides. MethodsThe study was carried out in 50 RA patients. CDT was measured using N Latex CDT immunonephelometric test, the results were presented in absolute and relative units. Anti-CCP were measured using the chemiluminescent method and rheumatoid factor by immunoturbidimetric method. Results80% of RA patients were positive for anti-CCP, 70% for RF and 62% for both, anti-CCP and RF. The level of %CDT was significantly elevated, but absolute CDT level was not changed. The mean absolute CDT concentration was higher in anti-CCP positive patients than that in anti-CCP negative. CDT (absolute and relative concentration) did not correlate with anti-CCP and RF. However, serum RF significantly correlated with anti-CCP. %CDT did not correlate with anti-CCP, but absolute level correlated with anti-CCP only in anti-CCP negative and RF negative patients. CDT did not correlate with RF, but solely with anti-CCP in anti-CCP negative patients. Anti-CCP correlated with DAS 28 only in anti-CCP negative RA, but CDT (absolute and relative units) correlated with DAS 28 in all patients and in anti-CCP positive RA. ConclusionsThese results suggest that the changes in CDT and anti-CCP concentrations are not associated with oneself and indicate on the independence of these posttranslational modifications in rheumatoid arthritis. Only the alterations in transferrin glycosylation reflected the activity of RA.

FRI0081 Titers of Anti-Ccp Antibodies, IL-6, Tnf-Alpha and CRP Are Associated with Increased Carotid Intima-Media Thickness: Cross-Sectional Analysis of A Rheumatoid Arthritis Group without Cardiovascular Risk Factors

BackgroundThe main causes of death in Rheumatoid Arthritis (RA) are cardiovascular events related to early atherosclerosis, myocardial infarction and congestive heart failure. The risk for cardiovascular disease it it not...

AB0885 Anti-Cyclic Citrullinated Peptide (ANTI-CCP) Antibodies in Polyarticular Juvenile Idiopathic Arthritis at Adulthood

BackgroundSeveral studies have already focused on anti-cyclic citrullinated peptide (anti-CCP) antibodies in juvenile idiopathic arthritis (JIA). Results of these studies showed that anti-CCP were associated with polyarticular sub-type (pJIA) and...

Incorrect Values in Table 4 of the Article by Kuller et al (Arthritis Rheumatol, March 2014)

In the article by Kuller et al in the March 2014 issue of Arthritis & Rheumatology (pages 497–507), there were several typographical errors in Table 4, column 5 (age-adjusted death rates per 1,000 person-years in the group of anti-CCP-negative patients with DMARD use at baseline). The corrected values for age-adjusted death rates (with 95% confidence intervals in parentheses) are as follows: general health excellent/very good 10.2 (3.2–33.6), general health good 16.7 (9.2–32.6), general health fair/poor 29.8 (14.2–62.8); no diabetes 16.8 (10.4–27.4), diabetes 27.5 (8.6–92.0); no CHD at baseline 16.7 (10.3-27.3), CHD at baseline 26.1 (10.2–71.6); physical function score on the SF-36 ≤85 17.9 (11.2–29.3), physical function score on the SF-36 >85 13.5 (3.6–56.6); waist circumference ≤88 cm 15.5 (8.0–30.3), waist circumference >88 cm 19.8 (11.1–37.7); total METs per week <2.5 20.0 (10.9–36.6), total METs per week 2.5–18.24 16.9 (9.0–32.1), total METs per week ≥18.25 18.2 (6.7–50.6); no hypertension 18.2 (10.3–32.5), hypertension 17.5 (8.8–36.4). Additionally, there were some typographical errors in Table 4, column 4 (weighted total in the group of anti-CCP–negative patients with DMARD use at baseline). The corrected values are as follows: general health excellent/very good 64, general health good 125, general health fair/poor 55. Finally, there was a typographical error in Table 1, column 3: the correct 95% confidence interval for the age-adjusted death rate in the group of anti-CCP-positive patients with no diabetes was 14.0–22.7. We regret the errors.

Plasma level of neopterin as a marker of disease activity in treated rheumatoid arthritis patients: Association with gender, disease activity and anti-CCP antibody

Immune system activation is known to be involved in the progression of rheumatoid arthritis (RA). The pro-inflammatory cytokine interferon-γ in various cells, including monocytes, induces neopterin production. Plasma level of neopterin has been measured in many autoimmune diseases and can be used as a marker of cellular immunity activation. In this study we measured the plasma level of neopterin in 418 treated RA patients and 398 age and sex matched healthy people by high pressure liquid chromatography (HPLC) method. Disease activity score was calculated in all patients by DAS-CRP method. Plasma level of neopterin was compared between RA and control groups. We also determined the association between neopterin level with gender and disease activity score in RA patients. Significantly higher level of neopterin was observed in RA patients compared to healthy controls. Moreover, there was higher neopterin level in male RA patients versus female patients. Plasma neopterin level was increased in patients with active disease and also was correlated with disease activity parameters. There was a significant correlation of plasma level of neopterin with age in both RA and control group and also age of onset and disease duration in RA patients. Anti-CCP positive patients had higher level of neopterin in comparison to anti-CCP negative patients and there was a significant correlation between neopterin level and anti-CCP titer. Our results indicated that neopterin is a sensitive marker for assaying background inflammation and disease activity score in RA patients and may be used as a marker for evaluation of therapy efficacy.

SAT0119 The relationship between inflammation and joint damage in rheumatoid arthritis is dependent on anti-CCP status

BackgroundJoint inflammation in Rheumatoid Arthritis is strongly associated with the development of joint damage. However, this association is highly different between patients, which may be explained by the presence of...

Anti-CCP antibody in patients with established rheumatoid arthritis: Does it predict adverse cardiovascular profile?

BackgroundRheumatoid arthritis (RA) is an independent risk factor for adverse cardiovascular (CV) events that accounts for a significant proportion of mortality among these patients. Anti-CCP antibodies are associated with higher frequency of extra-articular manifestations and poorer outcomes in RA. AimsTo determine the role of anti-cyclic citrullinated peptide (CCP) antibody as an independent risk factor for developing CV complications as documented by carotid intima medial thickness and abnormal echocardiography in established RA patients. Materials and methodsEighty patients of RA having disease duration of at least 3 years participated in this hospital-based, cross-sectional, and observational study. Forty patients were anti-CCP antibody positive. Patients of established RA having known CV risk factors, known heart disease, or family history of premature ischemic heart disease were excluded. ResultsAnti-CCP positive group had early morning stiffness, tender and swollen joint count, and c-reactive protein (CRP) level significantly higher than those in anti-CCP negative group. Average intima-medial thicknesses of common carotid arteries were also significantly higher among anti-CCP positive group (P = 0.029) and were positively correlated with patients' age and disease duration. Lower left ventricular ejection fraction and left ventricular diastolic dysfunction were more commonly dispersed among the anti-CCP positive patients with P values of 0.01 and 0.034, respectively. Mild pericardial thickening was documented among 12.5% patients of anti-CCP positive group, while none of the anti-CCP negative patients had similar findings in echocardiography. ConclusionThis study stressed on the important role of anti-CCP antibody in myocardial dysfunction due to inflammation in RA patients. Both atherosclerotic vascular involvement and cardiac abnormalities including pericardial, myocardial, and endocardial involvements were higher among anti-CCP positive RA patients. Hence, patients with high titer of anti-CCP antibody associated with prolonged disease duration and increased disease activity should be evaluated for CV morbidity more meticulously.

MSRA polymorphism is associated with the risk of rheumatoid arthritis in a Chinese population

Objectives: The expression of receptor activator of methionine sulfoxide reductase A (MSRA) and that of receptor activator of nuclear factor-kappa B (NF-κB) ligand (RANKL) are closely related to rheumatoid arthritis (RA). Our aim was to confirm whether MSRA and RANKL polymorphisms play a role in RA in a Chinese population.Methods: We investigated the presence of MSRA rs10903323 G/A and RANKL rs7984870 C/G polymorphisms in 329 patients with RA and 697 controls in a Chinese population. Genotyping was performed using matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS).Results: When the MSRA rs10903323 GG homozygote genotype was used as the reference group, the GA genotype was associated with a significantly increased risk for RA. In the dominant model, when the MSRA rs10903323 GG homozygote genotype was used as the reference group, the GA/AA genotypes were associated with a significantly increased susceptibility to RA. The RANKL rs7984870 C/G polymorphism was not associated with a risk for RA. In stratification analyses, a significantly increased risk for RA associated with the MSRA rs10903323 GA genotype was evident among male patients, older patients, C-reactive protein (CRP)-positive patients, and anti-cyclic citrullinated peptide (anti-CCP) negative patients compared with the MSRA rs10903323 GG genotype.Conclusions: These findings suggest that the MSRA rs10903323 G/A variant allele is associated with RA development, especially among male patients, older patients, CRP-positive patients, and anti-CCP negative patients.

Correlation of Anti-Cyclic Citrullinated Antibody with Hand Joint Erosion Score in Rheumatoid Arthritis Patients

Background/AimsTo examine the correlation between radiological joint damage and serological parameters in early rheumatoid arthritis (RA).MethodsThis retrospective study reviewed the records of 216 patients diagnosed with RA and classified them according to disease duration: group 1, ≤ 24 months; group 2, > 24 months; and group 3, all patients combined. The extent of joint damage was assessed from plain radiographs using a modified version of the Larsen method and compared among groups.ResultsThe mean radiographic joint damage score was significantly higher in patients who had established RA (10.1 points) compared with those who had early RA. In group 1, the inflammatory parameters, erythrocyte sedimentation rate, and C-reactive protein were positively correlated with the joint damage score, but rheumatoid factor (RF) and anti-cyclic citrullinated peptide (anti-CCP) antibody were not. A subgroup analysis revealed that the anti-CCP positive patients in groups 1 and 2 had greater joint damage scores than did the anti-CCP negative patients, but no difference in RF was observed between subgroups. Anti-CCP positivity was not significantly correlated with joint damage sores in group 3.ConclusionsAnti-CCP positivity was significantly correlated with more severe joint damage at diagnosis. A correlation was observed between the radiological joint damage score and inflammatory parameters in early and established RA, indicating that anti-CCP can serve as a diagnostic tool and predict structural joint damage. These findings suggest anti-CCP positive patients should receive aggressive therapeutic intervention.