Anikó Kapitány

Anti-citrullinated protein/peptide autoantibodies in association with genetic and environmental factors as indicators of disease outcome in rheumatoid arthritis.

Anti-citrullinated protein/peptide antibodies (ACPA) have recently emerged as sensitive and specific serological markers of rheumatoid arthritis (RA), providing superior alternative of the rheumatoid factor (RF) test in the laboratory diagnostics of RA. Citrullination is a post-translational modification of arginine by deimination, physiologically occurring during apoptosis, inflammation or keratinization. The presence of several citrullinated proteins has been demonstrated in the RA synovium. The identification of citrullinated epitopes as targets led to the development of the first and later second-generation anti-cyclic citrullinated peptide (anti-CCP) antibody assays. The anti-Sa antibody has been identified a decade ago; however, recent studies confirmed that anti-Sa is directed against citrullinated vimentin. The determination of ACPA may have important prognostic significance, since ACPA production can precede the onset of clinical RA symptoms by years. ACPA(+) individuals with early, undifferentiated arthritis may have higher risk to develop RA. ACPA has important prognostic role during the progression of RA and it has also been associated with pronounced radiographic progression. ACPA production has been associated with several genetic predisposing factors, including HLA-DRB1 and PTPN22 1858T alleles, as well as with environmental and lifestyle-related factors, primarily smoking and possibly, the use of oral contraceptives and excessive caffeine intake. Thus, the assessment of ACPA, in addition to clinical, radiographic and genetic outcome measures may be important to assess disease prognosis and aids to design effective, early therapeutic strategies.

Population screening for coeliac disease in primary care by district nurses using a rapid antibody test: diagnostic accuracy and feasibility study

Objective To evaluate the feasibility and diagnostic accuracy of screening for coeliac disease by rapid detection of IgA antibodies to tissue transglutaminase performed in primary care. Design District nurses screened 6 year old children using rapid antibody testing of finger prick blood. They also collected capillary blood samples for laboratory determination of IgA and IgG antibodies to endomysium and IgA antibodies to tissue transglutaminase. Children with positive rapid test results were directly sent for biopsy of the small intestine. Setting Primary care in Jász-Nagykun-Szolnok county, Hungary. Participants 2690 children (77% of 6 year olds living in the county) and 120 nurses. Main outcome measures Positivity for antibodies to endomysium or transglutaminase in the laboratory and coeliac disease confirmed at biopsy. Results 37 children (1.4%, 95% confidence interval 0.9% to 1.8%) had biopsy confirmed coeliac disease. Only five of these children had been diagnosed clinically before screening. Rapid testing had a 78.1% sensitivity (70.0% to 89.3%) and 100% specificity (88.4% to 100%) for a final diagnosis of coeliac disease by biopsy. Sensitivity was 65.1% (50.2% to 77.6%) and specificity was 100% (99.8% to 100%) compared with combined results of IgA and IgG laboratory tests. Trained laboratory workers detected 30 of the 31 newly diagnosed IgA competent patients with the rapid test kit used blindly. Median time to biopsy after a positive rapid test result was significantly shorter (20 days, range 4-148) than after a positive laboratory result (142 days, 70-256; P<0.001). Children with coeliac disease detected at screening were smaller and had worse health status than their peers but they improved on a gluten-free diet. Conclusions A simple rapid antibody test enabled primary care nurses to detect patients with coeliac disease in the community who were not picked up in clinical care. Extra training is needed to improve sensitivity.

Anti-Citrullinated Protein Antibodies in Rheumatoid Arthritis: As Good as it Gets?

Anti-citrullinated protein antibodies (ACPAs) have recently emerged as sensitive and specific serological markers of rheumatoid arthritis (RA), providing superior alternative of the rheumatoid factor (RF) test in the laboratory diagnostics of RA. The first members of this autoantibody family were anti-perinuclear factor (APF) and anti-keratin antibodies (AKA). It became evident that both APF and AKA recognize citrullinated epitopes of filaggrin. Citrullination is a post-translational modification of arginine by deimination, physiologically occurring during apoptosis, inflammation or keratinization. The presence of several citrullinated proteins has been demonstrated in the RA synovium. The identification of citrullinated epitopes as targets for anti-filaggrin antibodies led to the development of the first and later second generation anti-cyclic citrullinated peptide (anti-CCP) antibody assays. The widely used anti-CCP2 assays have high diagnostic sensitivity and specificity, and they also show important predictive and prognostic value in RA. The anti-Sa antibody has been identified a decade ago; however, recent studies confirmed that anti-Sa is directed against citrullinated vimentin, hence it is a new member of the family of ACPAs. The newly developed anti-mutated citrullinated vimentin (anti-MCV) assay has similar diagnostic performance than the anti-CCP2 ELISA; however, the diagnostic spectrum of the anti-MCV test is somewhat different from that of anti-CCP2. It’s especially useful in the diagnosis of RA in RF and anti-CCP2 seronegative patients. The combined application of anti-CCP2 and anti-MCV assays can improve the laboratory diagnostics of RA. The family of ACPAs is expected to expand; there is an increasing need for developing new diagnostic strategies after careful evaluation of the characteristics of the available assays.

Interaction of HLA-DRB1*03 and smoking for the development of anti-Jo-1 antibodies in adult idiopathic inflammatory myopathies: a European-wide case study

Objectives HLA-DRB1*03 is strongly associated with anti-Jo-1-positive idiopathic inflammatory myopathies (IIM) and there is now increasing evidence that Jo-1 antigen is preferentially expressed in lung tissue. This study examined whether smoking was associated with the development of anti-Jo-1 antibodies in HLA-DRB1*03-positive IIM. Methods IIM cases were selected with concurrent information regarding HLA-DRB1 status, smoking history and anti-Jo-1 antibody status. DNA was genotyped at DRB1 using a commercial sequence-specific oligonucleotide kit. Anti-Jo-1 antibody status was established using a line blot assay or immunoprecipitation. Results 557 Caucasian IIM patients were recruited from Hungary (181), UK (99), Sweden (94) and Czech Republic (183). Smoking frequency was increased in anti-Jo-1-positive IIM cases, and reached statistical significance in Hungarian IIM (45% Jo-1-positive vs 17% Jo-1-negative, OR 3.94, 95% CI 1.53 to 9.89, p<0.0001). A strong association between HLA-DRB1*03 and anti-Jo-1 status was observed across all four cohorts (DRB1*03 frequency: 74% Jo-1-positive vs 35% Jo-1-negative, OR 5.55, 95% CI 3.42 to 9.14, p<0.0001). The frequency of HLA-DRB1*03 was increased in smokers. The frequency of anti-Jo-1 was increased in DRB1*03-positive smokers vs DRB1*03-negative non-smokers (42% vs 8%, OR 7.75, 95% CI 4.21 to 14.28, p<0.0001) and DRB1*03-positive non-smokers (42% vs 31%, p=0.08). In DRB1*03-negative patients, anti-Jo-1 status between smokers and non-smokers was not significantly different. No significant interaction was noted between smoking and DRB1*03 status using anti-Jo-1 as the outcome measure. Conclusion Smoking appears to be associated with an increased risk of possession of anti-Jo-1 in HLA-DRB1*03-positive IIM cases. The authors hypothesise that an interaction between HLA-DRB1*03 and smoking may prime the development of anti-Jo-1 antibodies.

Gluten intake interferes with the humoral immune response to recombinant hepatitis B vaccine in patients with celiac disease.

OBJECTIVE. Patients with celiac disease, who often carry human leukocyte antigen-DR3;DQ2, are prone to inadequate response to hepatitis B immunization. We evaluated vaccine response in relation to disease activity and whether previous treatment with a gluten-free diet influences the achievement of protective antibody titers. PATIENTS AND METHODS. We studied 128 children and adolescents with celiac disease and 113 age-matched control subjects. Twenty-two patients with celiac disease were prospectively immunized after diagnosis during dietary treatment (group 1). A total of 106 (group 2) and the control subjects received vaccination by mass immunization in schools at 14 years of age regardless of diet status and when celiac disease was still undiagnosed in 27 of these children. Diet compliance and celiac disease activity were monitored by measurement of antibodies against transglutaminase and endomysium. Vaccine response was determined by measuring antihepatitis B antibodies from serum. RESULTS. The seroconversion after hepatitis B vaccination was 95.5% in group 1. All of these patients carried human leukocyte antigen DQ2. The response rate in group 2 was 50.9% and correlated with gluten intake (untreated patients: 25.9%, non-strict diet: 44.4%, strict diet: 61.4%). Treated and compliant patients did not significantly differ from control subjects (75.2%). Thirty-seven antihepatitis B–negative patients with celiac disease received a booster during a controlled gluten-free diet, and 36 (97.3%) seroconverted, irrespective of the presence of human leukocyte antigen DQ2. CONCLUSIONS. Nonresponse to recombinant hepatitis B surface antigen may be a sign of undiagnosed celiac disease. However, there is a good vaccine response in adequately treated patients. Human leukocyte antigen DQ alleles do not seem to have a primary role. Revaccination is recommended during a controlled gluten-free diet.

Association of rheumatoid arthritis with HLA-DR1 and HLA-DR4 in Hungary.

Abstract: Susceptibility to and outcome for rheumatoid arthritis (RA) have been associated with particular HLA‐DR alleles, but these alleles vary among ethnic groups and geographic areas. The frequency of HLA‐DR1 (HLA‐DRB1*0101, DRB1*0102) and HLA‐DR4 (DRB1*0401, DRB1*0404) alleles is elevated among Caucasian patients with RA. We studied a northeastern Hungarian population of RA patients to determine the frequency of HLA‐DR1 and HLA‐DR4 phenotypes in this population and to compare it with healthy control subjects, as well as to investigate whether the presence of these alleles could be a marker for RA. We performed HLA‐DRB1 genotyping (DRB1*01‐DRB1*16) in 83 RA patients and 55 healthy controls using polymerase chain reaction with sequence‐specific primers (PCR‐SSP). In the case of HLA‐DR1‐ or HLA‐DR4‐positive patients, the DR1 and DR4 subtypes were also determined. The frequency of HLA‐DR4 alleles was significantly higher in RA patients than in controls (31.3 vs. 10.9%; P < .05). HLA‐DR1, in particular, tended to be more frequent in patients than in controls (32.5 vs. 18.1%). Among the HLA‐DR4 subtypes, DRB1*0401 and DRB1*0404 were the most common alleles found in both groups. However, no significant differences were seen in the frequency of HLA‐DRB1*0401 and HLA‐DRB1*0404 between RA patients and controls. In contrast, HLA‐DRB1*0405 and HLA‐DRB1*0408 were significantly more common in RA patients than in control subjects. Among HLA‐DR1 subtypes, the DRB1*0101 allele was most commonly detected, but HLA‐DRB1*0101 as well as DRB1*0102 and DRB1*0105 were similarly frequent in RA patients and controls. HLA‐DR12 was more common among controls than in RA patients (18.1 vs. 0%; P < .05). Our results generally agree with the findings in other Caucasian populations. Nonetheless, we found differences in the frequency of HLA‐DR1 and HLA‐DR4 subtypes among Hungarian patients compared with reports from other geographic regions (e.g., Finland and Asia). Our data suggest that in northeastern Hungary, HLA‐DR4 as well as its subtypes DRB1*0405 and DRB1*0408 may be involved in susceptibility to RA, but HLA‐DR1 may not. In addition, the presence of HLA‐DR12, at least in Hungary, may protect from this disease.

Diagnostic significance of HLA-DQ typing in patients with previous coeliac disease diagnosis based on histology alone

Coeliac disease is strongly associated with human leukocyte antigen (HLA)‐DQ2 or DQ8 genotypes. The diagnosis is based on demonstrating crypt‐hyperplastic villous atrophy, endomysial or transglutaminase antibodies and correlation of disease activity with gluten intake.

New classification of the shared epitope in rheumatoid arthritis: impact on the production of various anti-citrullinated protein antibodies

OBJECTIVE HLA-DR [shared epitope (SE)] alleles have recently been re-classified into S1, S2, S3P and S3D groups. S2 and S3P have been associated with increased risk for RA. We assessed the impact of S1, S2, S3P and S3D alleles on anti-citrullinated protein antibody (ACPA) production. Instead of comparing allele-carriers to non-carriers, we studied each allele group individually, using the X/X (non-SE) genotype as reference. METHODS Serum and genomic DNA samples of 91 RA patients and 78 healthy controls were obtained. Various ACPAs and IgM RF were determined by ELISA. HLA-DRB1 genotyping and subtyping was performed by PCR. HLA-DRB1 alleles were re-classified as described above. Correlations between SE and ACPAs were determined. RESULTS Not only S2 and S3P, but, to a lesser extent, S1 and S3D alleles also predisposed to anti-cyclic citrullinated peptide (CCP) production (P < 0.0001, P = 0.004, P = 0.01 and P = 0.027, respectively), with the following hierarchy of association: S2+S3P > S1+S3D > X/X. Similar associations were observed for anti-citrullinated vimentin. Anti-citrullinated fibrinogen (CF) exerted a different association pattern with the strongest correlation with S1 alleles [odds ratio (OR) 16.00; P = 0.05]. In addition, HLA-DRB1*15 alleles may represent a special predisposing effect for anti-CF antibody production. Finally, in this study, RF production was associated only with the HLA-DRB1*0401 SE allele (P = 0.04). CONCLUSIONS Our approach of comparing individual S allele carriers with X/X genotype patients allowed us to perform unequivocal analyses and demonstrate new associations. Thus, novel subgroups of RA could be identified with potential relevance for prognosis and therapy.

Frequencies of genetic polymorphisms of TLR4 and CD14 and of HLA-DQ genotypes in children with celiac disease, type 1 diabetes mellitus, or both

Objectives: Besides the central role of the adaptive immune system, a disturbance of innate immunity is also involved in the pathogenesis of celiac disease (CD). Inasmuch as CD and type 1 diabetes mellitus (T1DM) frequently coexist because of a common genetic predisposition, our aim was to study the frequency of CD14 C-260T and TLR4 A+896G single nucleotide polymorphisms (SNPs) and the distribution of HLA-DQ genotypes in children affected by CD, T1DM, or both. Patients and Methods: TLR4 and CD14 SNPs were tested by polymerase chain reaction, followed by restriction fragment length polymorphism analysis in 80 children with T1DM, 100 children with CD, and 47 children with both CD and T1DM. Determination of HLA-DQ alleles was done by sequence-specific polymerase chain reaction. Frequencies were compared with those of healthy control children. Results: The prevalence of the homozygous CD14 C-260TT genotype was significantly (P = 0.0081) lower in children with T1DM but not in those with CD and T1DM, compared with control children. No difference was found in the genotype and allele frequencies of TLR4 between the studied groups. In patients with T1DM, the frequency of the homozygous HLA-DQ8 genotype was significantly higher than in CD, whereas the frequency of homozygous or heterozygous HLA-DQ2 genotypes did not differ from that in control children. In patients with CD, both homozygous and heterozygous HLA-DQ2 genotypes were significantly more frequent than in the control and T1DM groups, and no elevation in the frequency of the HLA-DQ8 genotypes was observed. In patients with T1DM and those with CD and T1DM, the occurrence of HLA-DQ2/8 heterozygosity was significantly higher than in children with CD only and in control children. Conclusions: Our results suggest that in patients with T1DM, the CD14 C-260TT homozygous genotype increases the risk for the development of CD. The distribution of HLA-DQ genotype is different in children with CD and T1DM than in children with CD or T1DM only. Determination of the HLA-DQ genotype in children with T1DM may help in estimating the risk for the development of CD.

Severe skin inflammation and filaggrin mutation similarly alter the skin barrier in patients with atopic dermatitis

Filaggrin (FLG) deficiency is a well‐known predisposing factor for the development of atopic dermatitis (AD). Decreased FLG expression can be the result of haploinsufficiency or severe inflammation, which can cause acquired FLG alterations. FLG mutations are related to several clinical and laboratory parameters of AD; however, some recent data seem to contradict these associations.