René R. P. de Vries

Cytomegalovirus in autoimmunity: T cell crossreactivity to viral antigen and autoantigen glutamic acid decarboxylase

Antigens of pathogenic microbes that mimic autoantigens are thought to be responsible for the activation of autoreactive T cells. Viral infections have been associated with the development of the neuroendocrine autoimmune diseases type 1 diabetes and stiff-man syndrome, but the mechanism is unknown. These diseases share glutamic acid decarboxylase (GAD65) as a major autoantigen. We screened synthetic peptide libraries dedicated to bind to HLA-DR3, which predisposes to both diseases, using clonal CD4+ T cells reactive to GAD65 isolated from a prediabetic stiff-man syndrome patient. Here we show that these GAD65-specific T cells crossreact with a peptide of the human cytomegalovirus (hCMV) major DNA-binding protein. This peptide was identified after database searching with a recognition pattern that had been deduced from the library studies. Furthermore, we showed that hCMV-derived epitope can be naturally processed by dendritic cells and recognized by GAD65 reactive T cells. Thus, hCMV may be involved in the loss of T cell tolerance to autoantigen GAD65 by a mechanism of molecular mimicry leading to autoimmunity.

Quantitative Heritability of Anti-Citrullinated Protein Antibody-Positive and Anti-Citrullinated Protein Antibody-Negative Rheumatoid Arthritis

OBJECTIVE The majority of genetic risk factors for rheumatoid arthritis (RA) are associated with anti-citrullinated protein antibody (ACPA)-positive RA, while far fewer genetic risk factors have been identified for ACPA-negative RA. This study was undertaken to quantify the contribution of genetic risk factors in general, and of the predisposing HLA-DRB1 shared epitope (SE) alleles in particular, to the ACPA-positive and ACPA-negative subsets of RA, by computing their heritability and assessing the contribution of the HLA SE alleles. METHODS One hundred forty-eight RA twin pairs, in which at least 1 twin of each pair had RA, were tested for ACPAs and typed for HLA-DRB1 genotypes. Heritability was assessed in a logistic regression model including a bivariate, normally distributed random effect, representing the contribution of unobserved genetic factors to RA susceptibility, with the correlation of the random effects fixed according to twin zygosity. The contribution of the HLA SE alleles to genetic variance was assessed using a similar model, except that estimates were based on genotype-specific population prevalences. RESULTS The heritability of RA among the twin pairs was 66% (95% confidence interval [95% CI] 44-75%). For ACPA-positive RA, the heritability was 68% (95% CI 55-79%), and for ACPA-negative RA it was 66% (95% CI 21-82%). Presence of the HLA SE alleles explained 18% (95% CI 16-19%) of the genetic variance of ACPA-positive RA but only 2.4% (95% CI 1.6-10%) of the genetic variance of ACPA-negative RA. CONCLUSION The heritability of ACPA-positive RA is comparable with that of ACPA-negative RA. These data indicate that genetic predisposition plays an important role in the pathogenesis of ACPA-negative RA, for which most individual genetic risk factors remain to be identified.

Protection against anti–citrullinated protein antibody–positive rheumatoid arthritis is predominantly associated with HLA–DRB1*1301: A meta-analysis of HLA–DRB1 associations with anti–citrullinated protein antibody–positive and anti–citrullinated protein antibody–negative rheumatoid arthritis in four European populations

OBJECTIVE The protective effect of HLA-DRB1 alleles on the development of rheumatoid arthritis (RA) is poorly understood. The aim of this study was to perform a meta-analysis of 4 European populations to investigate which HLA-DRB1 alleles are associated with protection in anti-citrullinated protein antibody (ACPA)-positive RA and ACPA-negative RA. METHODS Data for >2,800 patients and >3,000 control subjects for whom information on HLA-DRB1 typing and ACPA status was available were collected from 4 European countries: Norway, Sweden, The Netherlands, and Spain. The odds ratios (ORs) and 95% confidence intervals (95% CIs) associated with the different HLA-DRB1 alleles were analyzed in a combined meta-analysis focused on protective alleles and classifications. The analysis of ACPA-positive RA was stratified for the shared epitope (SE) alleles, to correct for skewing due to this association. RESULTS In ACPA-positive RA, the only alleles that conveyed protection after stratification for SE were HLA-DRB1*13 alleles (OR 0.54 [95% CI 0.38-0.77]). The protective effect of the allele classifications based on the DERAA and D70 sequences was no longer present after exclusion of DRB1*13 (for D70, OR 0.97 [95% CI 0.75-1.25]), indicating that DRB1*13, rather than the DERAA or D70 sequence as such, is associated with protection. Among the DRB1*13 alleles, only DRB1*1301 was associated with protection (OR 0.24 [95% CI 0.09-0.59]). Protection appeared to follow a north-to-south gradient, with the strongest association in northern European countries. In ACPA-negative RA, there were no robust associations with HLA-DRB1 alleles. CONCLUSION Our data do not support any of the classifications of protective alleles and indicate that protection against ACPA-positive RA is predominantly associated with HLA-DRB1*1301.

Hla class II association with rheumatoid arthritis: Facts and interpretations

We have reviewed the literature on the association of HLA class II with rheumatoid arthritis (RA). Strong linkage disequilibrium among DQB1, DQA1 and DRB1 alleles makes it difficult to evaluate the individual contribution of each locus. Nonetheless, there is a strong case for the role of DQB1*03 and *04 combined with DQA1*03 in susceptibility to severe RA while DQB1*0501 combined with DQA1*0101 and *0104 weakly predisposes to a mild form of RA. However, it is also clear that DRB1*0401 has a particular role in predisposition to the most severe form of the disease while other DRB1 alleles might provide protection. We would like to propose that in RA, as in type I diabetes, both DQ and DR loci contribute to predisposition to the disease.

Failure of neonatal hepatitis B vaccination: the role of HBV-DNA levels in hepatitis B carrier mothers and HLA antigens in neonates

In a hepatitis B vaccination program (1982-1992), 705 infants born to HBsAg-positive mothers received HBIg within 2 h of birth and were vaccinated according to a three- or four-dose vaccination schedule, starting either at 3 months or directly after birth. Eight children HBsAg-positive during the first year of life (group 1: infected nonresponders). To determine whether failure of the hepatitis B vaccination was due to perinatal high-level maternal viraemia or genetically determined infant nonresponsiveness to the vaccine, we measured HBsAg and anti-HBs levels in infants and HBeAg and hepatitis B virus-DNA levels in maternal serum, and determined the HLA type of the infants. Controls included 14 infants with a normal anti-HBs response 1 year after vaccination (group 2: noninfected responders) and all eight infants without HBsAg and anti-HBs 1 year after vaccination (group 3: noninfected low responders). HBsAg, HBeAg and anti-HBs were measured by radioimmunoassay (Abbott Laboratories), hepatitis B virus-DNA was measured quantitatively by solution hybridization for groups 1, 2, and 3 (Abbott hepatitis B virus-DNA assay, Abbott Laboratories), and HLA was characterized by microcytotoxicity test for groups 1 and 3. All infants in groups 1 and 2 were born to HBeAg carrier mothers, and those in group 3 to HBeAg-negative mothers. Hepatitis B virus-DNA levels in maternal serum in group 1 were significantly higher than in group 2 (Wilcoxon rank-sum test: p < 0.01). Hepatitis B virus-DNA was not observed in group 3 maternal serum samples.(ABSTRACT TRUNCATED AT 250 WORDS)

Identification of citrullinated vimentin peptides as T cell epitopes in HLA-DR4-positive patients with rheumatoid arthritis.

OBJECTIVE Antibodies directed against citrullinated proteins (ACPAs) are highly specific for rheumatoid arthritis (RA). The production of ACPAs is most likely dependent on the presence of T cells, since ACPAs undergo isotype switching and are associated with the shared epitope (SE)-containing HLA-DRB1 alleles. Vimentin is a likely candidate protein for T cell recognition, since >90% of patients positive for ACPAs that are reactive with (peptides derived from) citrullinated vimentin carry SE-containing HLA-DRB1 alleles. The aim of this study was to identify citrullinated vimentin peptides that are presented to HLA-DRB1*0401-restricted T cells. METHODS HLA-DR4-transgenic mice were immunized with all possible citrulline-containing peptides derived from vimentin, and T cell reactivity was analyzed. Peptides recognized in a citrulline-specific manner by T cells were selected and analyzed for their ability to be processed from the entire vimentin protein. A first inventory of the selected epitopes recognized by T cells was performed using peripheral blood mononuclear cells (PBMCs) from ACPA+, HLA-DR4+ patients with RA. RESULTS A citrulline-specific response was observed for 2 of the peptides analyzed in DR4-transgenic mice. These peptides were found to be naturally processed from the vimentin protein, since citrullinated vimentin was recognized by peptide-specific T cells. T cell reactivity against these peptides was also observed in cultures of PBMCs from RA patients. CONCLUSION This study identifies, for the first time, 2 naturally processed peptides from vimentin that are recognized by HLA-DRB1*0401-restricted T cells in a citrulline-specific manner. These peptides can be recognized by T cells in ACPA+, HLA-DR4+ patients with RA, as shown in a first inventory.

T-Cell Reactivity to β-Cell Membrane Antigens Associated With β-Cell Destruction in IDDM

Insulin-dependent diabetes mellitus (IDDM) results from a T-cell-mediated destruction of the insulin-producing β-cells. In this study, we designed a sensitive assay to detect and identify islet cell-reactive T-cells in patients with newly diagnosed IDDM. The relation between T-cell recognition of β-cell antigens with IDDM and the pathogenesis of the disease (the β-cell destruction process) was tested in a large group of IDDM patients and compared with T-cell responses in nondiabetic children with other chronic inflammations and in immunologically normal, age-matched control subjects. The results demonstrate that peripheral blood T-cells reacting with a β-cell membrane preparation enriched for insulin-secretory granule antigen were detectable in the majority of newly diagnosed IDDM patients (27 of 40 [67%]; mean stimulation index [SI] 37.0). Such reactivity was reduced postonset in IDDM patients proportionally to the duration of the disease (11 of 30 [37%]; mean SI 8.7). Nondiabetic age-matched control subjects showed no responses or moderate responses to the granule preparation (4 of 48 [8%]; mean SI 3.4). The magnitude of the T-cell response was significantly greater in newly diagnosed IDDM patients than in IDDM patients tested at least 2 years postonset (P < 0.001). Two children in remission for insulin dependency (so-called honeymoon period) displayed exceptionally high proliferative responses to insulin-secretory granules (mean SI 86.7). These results imply that T-cell recognition of insulin-secretory granule antigens is associated with IDDM and in particular with the immune-mediated process of β-cell destruction.

The telomeric part of the HLA region predisposes to rheumatoid arthritis independently of the class II loci

We have evaluated the possible contribution of genes besides DQ and DR to the association of HLA with rheumatoid arthritis (RA). To this end, we have looked at the allele distributions of six microsatellites, D6S1014, D6S2673, TNFalpha, MIB, C1-2-5, and C1-3-2 among 132 RA patients and 254 controls. We have defined 19 microsatellite clusters corresponding to previously described ancestral haplotypes. One of them was D6S1014*143-D6S273*139-TNFalpha*99-MIB*350-C1-2-5*196-C1-3-2*354, often found associated with DQB1*0201-DRB1*0301. As part of this microsatellite cluster, the allele MIB*350 was found to be a RA-predisposing factor, independent of DRB1*0301 and RA-predisposing haplotypes DQB1*03-DRB1*04 and DQB1*0501-DRB1*01. We conclude that the telomeric part of the HLA region contains a locus conferring predisposition to RA independently of HLA class II.

In Vitro Immune Responsiveness to Vaccinia Virus and HLA

Because several lines of evidence suggest that HLA products might have an important function in the immune response to infectious agents, we studied the possible relation between immune response to vaccinia virus and HLA phenotype in 79 soldiers who received a primary vaccination. A low in vitro response to vaccinia virus was associated with HLA-Cw3 both in 49 subjects tested three to four weeks after vaccination (P less than 0.001) and in the remaining 30 subjects tested five to 11 weeks after vaccination (P = 0.035). Responses to unrelated antigens and phytohemagglutinin of lymphocytes tested before, three to four weeks and five to 11 weeks after vaccination indicated that this association was specific for vaccinia virus and suggested that differences in immune response to vaccinia were reflected in temporarily altered immune responsiveness to unrelated antigens. Our results indicate that HLA-Cw3 or an HLA product associated with Cw3 is involved in the cellular immune response to vaccinia virus.

Protective effect of noninherited maternal HLA-DR antigens on rheumatoid arthritis development

Rheumatoid arthritis (RA) is a complex genetic disorder in which the HLA-region contributes most to the genetic risk. HLA-DRB1-molecules containing the amino acid sequence DERAA (i.e., HLA-DRB1*0103, *0402, *1102, *1103, *1301, *1302, and *1304) are associated with protection from RA. It has been proposed that not only inherited but also noninherited HLA-antigens from the mother (NIMA) can influence RA-susceptibility. Up to now, no protective NIMAs were described. Here, we studied whether DERAA-containing HLA-DRB1-alleles as NIMA are associated with a protective effect. One hundred seventy-nine families were studied, 88 from the Netherlands and 91 from the United Kingdom. The frequency of DERAA-containing HLA-DRB1-alleles of the Dutch mothers (16.1%), but not of the fathers (26.2%), was lower compared with the general Dutch population (29.3%; P = 0.02). This was replicated in the English set of patients and controls (P = 0.01). Further, of all families, 45 contained at least one DERAA-negative child with RA and at least one DERAA-positive parent. The odds for the DERAA-negative RA patients of having a DERAA-positive mother was significantly lower compared with having a DERAA-positive father (OR 0.25; P = 0.003). These data show a protective NIMA-effect in a human autoimmune disease and indicate that a DERAA-positive mother can transfer protection against RA to her DERAA-negative child.