Production Of anti-CCP Antibodies Research Articles

Alterations and abnormal expression of A20 in peripheral monocyte subtypes in patients with rheumatoid arthritis.

As the precursors of macrophages and osteoclasts, monocytes play an important role in the pathogenesis of rheumatoid arthritis (RA). Since the deficiency of zinc-finger protein A20 in myeloid cells triggers erosive polyarthritis resembling RA, A20 in monocytes may play a protective role in RA. In the present study, we aimed to investigate the abnormality of monocyte subtypes and the expression of zinc-finger protein A20 in RA. Peripheral blood mononuclear cells and clinical data were collected from RA patients and healthy controls (HCs). Monocyte subtypes and A20 expression were determined through flow cytometry and compared between the two groups. Correlations between monocyte subtypes, A20 expression, and clinical data were analyzed. A total of 43 RA patients and 23 HCs were included in the present study. RA patients had higher absolute monocyte counts (p < 0.001) in the peripheral blood. The proportions and counts of intermediate monocytes (IMs) (both p < 0.001) and non-classical monocytes (NCMs) were higher (both p < 0.001) in RA patients. The expression of A20 in IMs (p < 0.001) was lower in RA patients compared with that in the HCs. Furthermore, the expression of A20 in IMs was negatively correlated with the anti-cyclic citrullinated peptide (CCP) antibody level in RA patients (r = - 0.409, p = 0.01). The expression of A20 in NCMs was positively correlated with modified total Sharp score (mTSS) in RA patients (r = 0.471, p = 0.02). Collectively, we proved that IMs and NCMs were increased in RA patients, suggesting that they played a suggestive role in the pathogenesis of RA. Furthermore, the downregulation of A20 in IMs might be correlated with anti-CCP antibody production. The A20 expression in NCMs might affect bone erosion in RA. Key Points • IMs and NCMs were increased in the peripheral blood of RA patients, suggesting their pathogenic role in RA. • The decreased expression of zinc-finger protein A20 in IMs of RA patients suggested the protective role of A20 in RA. • The negative correlation between the A20 expression in IMs and anti-CCP antibody revealed that A20 in IMs might be related to the formation of anti-CCP antibodies. • The positive correlation between the A20 expression in NCMs and mTSS revealed that A20 in NCMs might affect the bone erosion in RA.

Abatacept reduces disease activity of rheumatoid arthritis independently of modulating anti-citrullinated peptide antibody production

Abatacept may exert its clinical effect on rheumatoid arthritis (RA) by suppressing anti-cyclic citrullinated peptide (CCP) antibody production. This study was undertaken to test this hypothesis by examining the changes of disease activity of RA and anti-CCP antibody levels over time after starting abatacept. Sixty Japanese RA patients who started abatacept were included in this multicenter, prospective observational study. Simple Disease Activity Index (SDAI) and anti-CCP antibody levels were evaluated at 12, 24, and 52 weeks. The mean SDAI score significantly decreased within 12 weeks after starting abatacept and was maintained thereafter. On the contrary, the mean anti-CCP antibody levels did not change until 52 weeks. At the individual level, there were substantial changes of anti-CCP antibody levels, but these were not correlated with the changes of disease activity at any time points. Thus, abatacept reduces the disease activity of RA independently of modulating anti-CCP antibody production.

Anti-cyclic citrullinated peptide antibody titers decrease in rheumatoid arthritis patients treated with tocilizumab: A pilot study

Objectives: To analyze the effects of tocilizumab on peripheral B-cell subpopulation and its ability to produce anti-cyclic citrullinated peptide (CCP) antibody in patients with rheumatoid arthritis (RA).Methods: Thirteen consecutive RA patients initiated with tocilizumab were enrolled in our prospective study. Anti-CCP antibody titers and clinical parameters were evaluated during treatment. Peripheral blood B-cell subsets were analyzed using flow cytometry according to the Human Immunology Project.Results: Disease activity was significantly improved and anti-CCP antibody titers significantly decreased at week 24 compared to baseline. The percentages of post-switch memory B cells in CD19+ cells transiently increased at week 12, but there was no significant difference in any of the investigated B-cell subpopulations at week 24 compared to baseline. The ratios of post-switch memory to naïve B cells (post-switch/naïve) correlated negatively with anti-CCP antibody titers regardless of the time-points.Conclusion: Our study indicated that tocilizumab has a potential to reduce anti-CCP antibody production presumably by affecting post-switch/naïve ratio, and that anti-CCP antibody titers reflect B-cell distribution/subpopulation. As anti-CCP antibodies are produced in lymph nodes or ectopic lymphoid structures in synovial tissues, not in circulation, transient increment of post-switch memory B cells after tocilizumab treatment may reflect the altered balance of B-cell distribution between circulation and arthritic joints, resulting in suppressed production of anti-CCP antibody in situ.

Autophagy generates citrullinated peptides in human synoviocytes: a possible trigger for anti-citrullinated peptide antibodies

Autophagy may represent a functional processing event that creates a substrate for autoreactivity. In particular, autophagy may play a role in the pathogenesis of RA, since autophagy is a key cellular event involved in the generation of citrullinated peptides, with consequent breakage of tolerance. Thus, in RA, autophagy may be the common feature in several situations (including smoking, joint injury and infection) that may drive the adaptive responses to citrullinated self-proteins. The aim of this study was the analysis, in vitro, of the role of autophagy in the generation of citrullinated peptides and, in vivo, of the relationship between autophagy and the production of anti-CCP antibodies (Abs). For autophagy induction, fibroblast-like synoviocytes, primary fibroblasts and monocytes were stimulated with tunicamycin or rapamycin. Peptidyl arginine deiminase activity was tested by enzyme-linked immunosorbent assay, and protein citrullination was evaluated by western blotting. The main citrullinated RA candidate antigens, vimentin, α-enolase and filaggrin, were demonstrated by immunoprecipitation. The relationship between autophagy and anti-CCP Abs was analysed in 30 early-active RA patients. Our results demonstrated in vitro a role for autophagy in the citrullination process. Cells treated with tunicamycin or rapamycin showed peptidyl arginine deiminase 4 activation, with consequent protein citrullination. Immunoblotting and immunoprecipitation experiments, using specific Abs, identified the main citrullinated proteins: vimentin, α-enolase and filaggrin. In vivo, a significant association between levels of autophagy and anti-CCP Abs was observed in treatment-naïve early-active RA patients. These findings support the view that the processing of proteins in autophagy generates citrullinated peptides recognized by the immune system in RA.

Interactions between smoking, increased serum levels of anti-CCP antibodies, rheumatoid factors, and erosive joint disease in patients with early, untreated rheumatoid arthritis

Objectives: To determine to what extent shared epitopes, smoking, and anti-cyclic citrullinated peptide (anti-CCP) antibodies are associated with disease activity and erosive disease in patients with rheumatoid arthritis (RA) at disease onset.Method: RA patients not previously treated with disease-modifying anti-rheumatic drugs (DMARDs) and with a disease duration of < 6 months (CIMESTRA study) were examined for shared epitopes, anti-CCP antibodies, immunoglobulin M rheumatoid factor (IgM-RF) and IgA-RF, radiographic erosive changes in hands and feet, and clinical disease activity.Results: The study comprised 153 patients, of whom 104 (68%) were ever-smokers. The prevalence of patients with 0, 1, or 2 shared epitopes was 40 (48%), 71 (49%), and 33 (23%), respectively. Anti-CCP antibodies, IgM-RF, and IgA-RF were present in 89 (58%), 99 (65%), and 82 (54%) patients, respectively. Among smokers, erosive disease was associated with anti-CCP antibodies [odds ratio (OR) 3.9, 95% confidence interval (CI) 1.6–9.3], IgM-RF (OR 4.9, 95% CI 1.9–12), and IgA-RF (OR 2.8, 95% CI 1.2–6.4) but absent with regard to shared epitopes. Among never-smokers, erosive disease was not associated with either shared epitopes or antibodies. All antibody levels measured were associated with smoking and shared epitopes.Conclusions: Shared epitopes and smoking were associated with the production of anti-CCP antibodies and rheumatoid factors of IgM and IgA isotypes, which again were associated with erosive disease at presentation only in smokers. As shared epitopes and smoking were not directly associated with erosive disease, smoking may enhance the development of erosive disease in RA at different levels or through separate pathways.

THU0238 Risk Factors for the Development of Anti-Citrullinated Protein Antibodies in Individuals Genetically at Risk for RA

BackgroundThe pathophysiology of rheumatoid arthritis (RA) is currently viewed as a process that starts with a pathologic activation of the immune system that eventually leads to the clinical manifestation of...

Contribution of LILRB1 polymorphism and HLA-DRB1-shared epitope to rheumatoid arthritis

Objectives The LILRB1 gene has recently been associated with rheumatoid arthritis (RA) susceptibility in HLA-DRB1-shared epitope (SE) negative Japanese individuals. Since the contribution of the LILRB1 polymorphism to RA susceptibility may vary among ethnic populations, we examined this association in a group of Caucasian patients. The frequency of LILRB1 alleles was also determined in patients according to the presence of DRB1-SE. Methods Samples from 103 RA patients and 107 healthy controls were randomly collected. Polymorphism of the LILRB1 gene was analyzed by sequencing with primers that amplified intron 3 and exon 4. Results The frequencies of LILRB1 alleles in RA patients did not differ from those of controls. However, when patients and controls were grouped according to SE, the PE-01/01 genotype was less frequent in negative-SE patients than in controls. Whereas SE is associated with higher anti-CCP antibody levels, as expected, the production of anti-CCP antibodies was lower in negative-SE patients with PE-01/01 genotype. Moreover, radiographic damage in hand and feet of SE-negative PE-01/01 patients was less severe than in patients with other genotypes. Conclusions The participation of this LILRB1 polymorphism in the RA pathogenesis of this Caucasian cohort differed from that reported in a Japanese sample. Our findings suggest that the LILRB1-PE-01/01 genotype could exert a protective role in RA susceptibility and disease severity in the absence of SE.

Usefulness of anti-cyclic citrullinate peptide antibody determination in synovial fluid analysis of patients with rheumatoid arthritis

To assess the role of anti-cyclic citrullinated peptide (CCP) antibody detection in synovial fluid (SF) of RA patients compared to OA patients. We evaluated in 25 RA subjects and 14 OA patients, presenting a knee-joint effusion, the main clinical and laboratory parameters including the number of painful and/or swollen joints, Ritchie index, morning stiffness, ESR, CRP and analysis of SF obtained by therapeutic arthrocentesis. IgG anti-CCP (ELISA), rheumatoid factor (RF) and total IgG (nephelometry method) were measured in SF and paired serum samples. We found anti-CCP antibodies and RF in 64% (16/25) and 60% (15/25) of RA sera, respectively; 72% (18/25) of RA patients were positive for anti-CCP antibodies or RF. We found a higher SF/serum ratio for anti-CCP (p<0.004) compared to that for total IgG. The calculation of anti-CCP concentration as IgG anti-CCP (units)/total IgG (g L-1) revealed higher values in SF than in serum (p<0.046) in RA patients. Among these, correlation analysis showed that anti-CCP/total IgG values in SF correlated with the relative concentration of serum anti-CCP/total IgG (rs=0.842; p<0.00001) and serum anti-CCP antibody levels (rs=0.799; p<0.0001). We did not find any correlation between SF anti-CCP levels and the main characteristics of SF as well as the clinical or laboratory parameters. Our study give evidence for a preferential production of anti-CCP antibodies at RA joint level, confirming the pathogenetic role of these autoantibodies. Moreover, SF determination of anti-CCP, corrected for the total amount of the corresponding immunoglobulin, may be helpful as diagnostic tool in selected cases.

Toll-Like Receptor 4 Is Involved in Inflammatory and Joint Destructive Pathways in Collagen-Induced Arthritis in DBA1J Mice

In rheumatoid arthritis, a significant proportion of cytokine and chemokine synthesis is attributed to innate immune mechanisms. TLR4 is a prominent innate receptor since several endogenous ligands known to activate the innate immune system bind to it and may thereby promote joint inflammation. We generated TLR4 deficient DBA1J mice by backcrossing the TLR4 mutation present in C3H/HeJ strain onto the DBA1J strain and investigated the course of collagen-induced arthritis in TLR4 deficient mice in comparison to wild type littermates. The incidence of collagen- induced arthritis was significantly lower in TLR4 deficient compared to wild type mice (59 percent vs. 100 percent). The severity of arthritis was reduced in the TLR4 deficient mice compared to wild type littermates (mean maximum score 2,54 vs. 6,25). Mice deficient for TLR4 were virtually protected from cartilage destruction, and infiltration of inflammatory cells was reduced compared to wt mice. In parallel to the decreased clinical severity, lower anti-CCP antibody concentrations and lower IL-17 concentrations were found in the TLR4 deficient mice. The study further supports the role of TLR4 in the propagation of joint inflammation and destruction. Moreover, since deficiency in TLR4 led to decreased IL-17 and anti-CCP antibody production, the results indicate a link between TLR4 stimulation and the adaptive autoimmune response. This mechanism might be relevant in human rheumatoid arthritis, possibly in response to activating endogenous ligands in the affected joints.

Contribution of an adenine to guanine single nucleotide polymorphism of the matrix metalloproteinase-13 (MMP-13) −77 promoter region to the production of anticyclic citrullinated peptide antibodies in patients with HLA-DRB1*shared epitope-negative rheumatoid arthritis

We examined whether matrix metalloproteinase-13 (MMP-13) contributes to disease susceptibility or severity of rheumatoid arthritis (RA). Eighty-seven patients with RA whose disease duration was <2 years and 71 healthy controls were enrolled in the study. Adenine (A) to guanine (G) single nucleotide polymorphism (SNP) of the −77 MMP-13 promoter region in RA and healthy controls was determined by polymerase chain reaction–restriction fragment length polymorphism (PCR-RFLP) technique. Human leukocyte antigen (HLA)-DRB1 genotyping was also performed using the same populations. Anticyclic citrullinated peptide (anti-CCP) antibodies from RA patients at entry were studied, and their relationships were examined. The genotype and allele frequency of SNP of MMP-13 at −77 did not differ between RA patients and healthy controls. We focused on the RA patients who were negative for HLA-DRB1*shared epitope (SE) alleles and found that the seropositivity of anti-CCP antibodies with a titer >25 U/ml was high in the A/A genotype compared with the G/G genotype. The same characteristic was also found in HLA-DRB1*0405 allele-negative patients. Our data suggest that SNP of the −77 MMP-13 promoter region acts as a surrogate marker of anti-CCP antibody production in HLA-DRB1*SE allele-negative RA patients, which may reflect RA severity.

Specific expression of PAD4 and citrullinated proteins in lung cancer is not associated with anti-CCP antibody production

Anti-citrullinated protein antibodies (ACPAs), produced against citrullinated proteins, are diagnostic and prognostic markers of rheumatoid arthritis (RA). The underlying mechanism that explains the connection of smoking, citrullination [catalyzed by peptidyl arginine deiminases (PADs)] and ACPAs is still unclarified in RA. Thus, we searched for a non-arthritic model in which an increased cell death allows the formation of autoantibodies. Data supporting that lung cancer might be a good candidate are as follows: (i) smoking plays a role in its pathogenesis, (ii) the disease is frequently accompanied by paraneoplastic syndrome, (iii) smoking increases citrullination in the lung, (iv) various types of malignancies are associated with increased citrullination and (v) lung cancer tissue shows similarities with RA synovium. Serum PAD4, rheumatoid factor (RF) and ACPA levels were measured in 42 lung cancer patients; expression of cytokeratin 7 (CK7), PAD4 and citrullinated proteins was visualized in 113 lung cancer tissues. All parameters were analyzed in correlation with smoking history. None of the patients had polyarthritis or autoimmune disease. Significantly increased RF levels were associated with higher PAD4 levels in smoker lung cancer patients compared with non-smokers. Both PAD4 and citrullination immunostaining strongly correlated with that of CK7 in lung cancer, however, did not differ according to smoking history. Two of 30 smoker lung cancer patients had high anti-cyclic citrullinated peptide levels. In conclusion, PAD4 and citrullination may be helpful in distinguishing lung cancer from healthy tissue. Smoking, abnormal serum PAD4 and RF levels may not be sufficient for the production of ACPAs and development of autoimmunity.

Increased serum PAD4 and RF in lung cancer is not associated with anti CCP antibody production

BackgroundRheumatoid arthritis (RA) is characterised by anticitrullinated protein antibodies (ACPAs), produced against citrullinated proteins. In the pathogenesis of the disease the interaction of environment and genetics have a role as...

Association study of single nucleotide polymorphisms in pre-miRNA and rheumatoid arthritis in a Han Chinese population

The aim of this study was to perform an association study between two single nucleotide polymorphisms (SNPs) rs2910164 G>C and rs3746444 T>C in pre-miRNA (hsa-mir-146a and hsa-mir-499) and rheumatoid arthritis (RA) in the Han Chinese population. 208 Han Chinese patients with RA and 240 healthy controls were recruited in this study. The SNPs was genotyped by polymerase chain reaction-restriction fragment length polymorphism. Anti-cyclic citrullinated peptide (anti-CCP) antibody was measured by enzyme linked immunosorbent assay and rheumatoid factor (RF) was measured by rate nephelometry. The genotype frequencies between cases and controls were compared by χ(2) analysis. No significant association between the SNPs (rs2910164 and rs3746444) and RA was observed (P = 0.631 and 0.775, respectively), and the SNPs did not show any association with the RF-positive (P = 0.631 and 0.775, respectively). However, there was a significant difference on the level of anti-CCP antibody between different genotypes in rs3746444 (P = 0.007). The heterozygote CT had significantly higher level of anti-CCP antibody compared with homozygote CC and TT (P = 0.054 and 0.003, respectively). We first investigated the association between the SNPs (rs2910164 G>C and rs3746444 T>C) in the pre-miRNA (hsa-mir-146a and hsa-mir-499) and RA in a Han Chinese population. We did not find a significant association between the SNPs and the susceptibility to RA, while the SNP rs3746444 may affect anti-CCP antibody production.

Contribution of an adenine to guanine single nucleotide polymorphism of the matrix metalloproteinase-13 (MMP-13) −77 promoter region to the production of anticyclic citrullinated peptide antibodies in patients with HLA-DRB1*shared epitope-negative rheumatoid arthritis

We examined whether matrix metalloproteinase-13 (MMP-13) contributes to disease susceptibility or severity of rheumatoid arthritis (RA). Eighty-seven patients with RA whose disease duration was <2 years and 71 healthy controls were enrolled in the study. Adenine (A) to guanine (G) single nucleotide polymorphism (SNP) of the -77 MMP-13 promoter region in RA and healthy controls was determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique. Human leukocyte antigen (HLA)-DRB1 genotyping was also performed using the same populations. Anticyclic citrullinated peptide (anti-CCP) antibodies from RA patients at entry were studied, and their relationships were examined. The genotype and allele frequency of SNP of MMP-13 at -77 did not differ between RA patients and healthy controls. We focused on the RA patients who were negative for HLA-DRB1*shared epitope (SE) alleles and found that the seropositivity of anti-CCP antibodies with a titer >25 U/ml was high in the A/A genotype compared with the G/G genotype. The same characteristic was also found in HLA-DRB1*0405 allele-negative patients. Our data suggest that SNP of the -77 MMP-13 promoter region acts as a surrogate marker of anti-CCP antibody production in HLA-DRB1*SE allele-negative RA patients, which may reflect RA severity.

Anti-cyclic citrullinated peptide antibody (anti-CCP antibody) is present in the sera of patients with dementia of Alzheimer’s type in Asian

In the hippocampi of Alzheimer's disease (AD) patients, aberrant expression of citrullinated proteins and peptidylarginase 2 (PADI2) has been identified. We explored the functional roles of these proteins by means of detection of serum anti-cyclic citrullinated peptide antibody (anti-CCP antibody) in patients with dementia of Alzheimer's type (DAT). Sera were obtained from 42 patients with DAT, 30 patients with other neurological disorders and 42 healthy controls. Gender ratio and age were comparable among the three groups. The level of anti-CCP antibody in sera was examined by ELISA. Anti-CCP antibody was not found in the 30 patients with other neurological disorders, and only one of the 42 healthy controls (2.4%) was positive. However, surprisingly, anti-CCP antibody was clearly detected in eight of the 42 DAT patients. Anti-CCP antibody appears to be a simple and early serologic biomarker for DAT among dementia patients. Additionally, our data imply that citrullinated proteins accumulated in the astrocytes of AD patients acquire neo-antigenicity, inducing anti-CCP antibody production.

Hormonal replacement therapy may reduce the risk for RA in women with early arthritis who carry HLA-DRB1 *01 and/or *04 alleles by protecting against the production of anti-CCP: results from the ESPOIR cohort

ObjectiveTo assess the effect of reproductive factors, especially hormone replacement therapy (HRT) and its interaction with HLA-DRB1 *01 and/or *04 alleles on the diagnosis of rheumatoid arthritis (RA) and the...

Rheumatology

Rheumatology

Association of allograft inflammatory factor‐1 gene polymorphism with rheumatoid arthritis

Human allograft inflammatory factor-1 (AIF-1) is a cytoplasmic protein primarily identified in human and rat allografts, and data from several studies suggest an important role for AIF-1 in inflammatory processes. The aim of this study was to examine the association between AIF1 rs2269475:C>T polymorphism and rheumatoid arthritis (RA). AIF1 genotype was determined by means of the polymerase chain reaction-restriction fragment length polymorphism method in 276 White patients with RA and 236 healthy subjects. The frequency of the AIF1 rs2269475 TT genotype was significantly higher in the patients with RA than in the controls (OR=5.59, 95% CI: 1.22-25.55). The frequency of T allele carriers in the patient group with RA was 31.9% vs 19.1% among controls (P=0.0003). Moreover, the frequency of individuals positive for anti-cyclic citrullinated peptide (anti-CCP) antibodies was significantly elevated in the T allele carriers (OR=8.82, 95% CI: 2.06-37.7). It is noteworthy that no significant linkage disequilibria between the AIF1 C/T and DRB1 alleles associated with RA development and anti-CCP antibody production [including the most frequent, i.e. *04 (32.7%) and *01 (23.5%)] (P>0.1) were found. Our results show that the AIF1 rs2269475 T allele is associated with increased risk of RA development. Moreover, the frequency of individuals positive for anti-CCP antibodies is significantly increased among T allele carriers.

Regulation of anti–cyclic citrullinated peptide antibodies in rheumatoid arthritis: Contrasting effects of HLA–DR3 and the shared epitope alleles

To examine the association between HLA-DRB1 alleles and the production of anti-cyclic citrullinated peptide (anti-CCP) and rheumatoid factor (RF) autoantibodies in patients with rheumatoid arthritis (RA). We studied 1,723 Caucasian RA patients enrolled in the North American Rheumatoid Arthritis Consortium (NARAC) family cohort and the Study of New Onset Rheumatoid Arthritis (SONORA) cohort. All patients were tested for anti-CCP antibodies (by enzyme-linked immunosorbent assay), RF (by nephelometry), and HLA-DR genotype (by polymerase chain reaction and sequence-specific oligonucleotide hybridization). When controlled for the presence of RF, anti-CCP positivity was strongly associated with the HLA-DRB1 shared epitope (SE). In RF+ patients, the presence of the SE was very significantly associated with anti-CCP positivity, with an odds ratio (OR) of 5.8 and a 95% confidence interval (95% CI) of 4.1-8.3. This relationship was also seen in RF- patients (OR 3.1 [95% CI 1.8-5.3]). In contrast, RF positivity was not significantly associated with presence of the SE independently of anti-CCP antibodies. Strikingly, HLA-DRB1*03 was strongly associated with reduced anti-CCP titers, even after controlling for the presence of the SE and restricting the analysis to anti-CCP+ patients. HLA-DR3 was also associated with anti-CCP- RA in our population. The HLA-DRB1 SE is strongly associated with the production of anti-CCP antibodies, but not RF. In contrast, HLA-DR3 alleles are associated with anti-CCP- disease and with lower levels of anti-CCP antibodies, even when controlling for the SE. These data emphasize the complexity of the genetic effects of the major histocompatibility complex on the RA phenotype.

Association between HLA class II genes and autoantibodies to cyclic citrullinated peptides (CCPs) influences the severity of rheumatoid arthritis.

The functional role of HLA class II molecules in the pathogenesis of rheumatoid arthritis (RA) is unclear. HLA class II molecules are involved in the interaction between T and B lymphocytes required for long-lived B cell responses and generation of high-affinity IgG antibodies. We undertook this study to investigate the relationship between HLA class II gene polymorphisms and RA-specific IgG antibodies against cyclic citrullinated peptides (anti-CCP antibodies). High-resolution HLA-DR and DQ typing and anti-CCP-2 antibody testing were performed on 268 RA patients from the Early Arthritis Clinic cohort at the Department of Rheumatology of the Leiden University Medical Center. The presence of anti-CCP antibodies was analyzed in carriers of the different DR and DQ alleles. Disease progression was measured over a period of 4 years by scoring radiographs of the hands and feet using the Sharp/van der Heijde method. Carriership of the individual alleles HLA-DRB1*0401, DRB1*1001, DQB1*0302, and DQB1*0501 was associated with the presence of anti-CCP antibodies. Carriers of DQ-DR genotypes containing proposed RA susceptibility alleles were significantly more often anti-CCP antibody positive. Carriership of one or two HLA-DRB1 shared epitope (SE) alleles was significantly associated with production of anti-CCP antibodies (odds ratio [OR] 3.3, 95% confidence interval [95% CI] 1.8-6.0 and OR 13.3, 95% CI 4.6-40.4, respectively). An increased rate of joint destruction was observed in SE+, anti-CCP+ patients (mean Sharp score 7.6 points per year) compared with that in SE-, anti-CCP+ patients (2.4 points per year) (P = 0.04), SE+, anti-CCP- patients (1.6 points per year) (P < 0.001), and SE-, anti-CCP- patients (1.6 points per year) (P < 0.001). HLA class II RA susceptibility alleles are associated with production of anti-CCP antibodies. Moreover, more severe disease progression is found in RA patients with both anti-CCP antibodies and SE alleles.