Association of rheumatoid arthritis with a dominant DR1/Dw4/Dw14 sequence motif, but not with T cell receptor beta chain gene alleles or haplotypes

Protein-altering germline mutations implicate novel genes related to lung cancer development

Few germline mutations are known to affect lung cancer risk. We performed analyses of rare variants from 39,146 individuals of European ancestry and investigated gene expression levels in 7,773 samples. We find a large-effect association with an ATM L2307F (rs56009889) mutation in adenocarcinoma for discovery (adjusted Odds Ratio = 8.82, P = 1.18 × 10-15) and replication (adjusted OR = 2.93, P = 2.22 × 10-3) that is more pronounced in females (adjusted OR = 6.81 and 3.19 and for discovery and replication). We observe an excess loss of heterozygosity in lung tumors among ATM L2307F allele carriers. L2307F is more frequent (4%) among Ashkenazi Jewish populations. We also observe an association in discovery (adjusted OR = 2.61, P = 7.98 × 10-22) and replication datasets (adjusted OR = 1.55, P = 0.06) with a loss-of-function mutation, Q4X (rs150665432) of an uncharacterized gene, KIAA0930. Our findings implicate germline genetic variants in ATM with lung cancer susceptibility and suggest KIAA0930 as a novel candidate gene for lung cancer risk.

Autoimmunity in Rheumatic Diseases Is Induced by Microbial Infections via Crossreactivity or Molecular Mimicry

A general consensus supports fundamental roles for both genetic and environmental, mainly microbial, factors in the development of autoimmune diseases. One form of autoimmune rheumatic diseases is confined to a group of nonpyogenic conditions which are usually preceded by or associated with either explicit or occult infections. A previous history of clinical pharyngitis, gastroenteritis/urethritis, or tick-borne skin manifestation can be obtained from patients with rheumatic fever, reactive arthritis, or Lyme disease, respectively, whilst, other rheumatic diseases like rheumatoid arthritis (RA), ankylosing spondylitis (AS), and Crohn's disease (CD) are usually lacking such an association with a noticeable microbial infection. A great amount of data supports the notion that RA is most likely caused by Proteus asymptomatic urinary tract infections, whilst AS and CD are caused by subclinical bowel infections with Klebsiella microbes. Molecular mimicry is the main pathogenetic mechanism that can explain these forms of microbe-disease associations, where the causative microbes can initiate the disease with consequent productions of antibacterial and crossreactive autoantibodies which have a great impact in the propagation and the development of these diseases.

Rheumatoid arthritis is linked to Proteus--the evidence

Rheumatoid arthritis (RA) is a chronic inflammatory arthritic and potentially disabling condition, mainly affecting women of middle age and having characteristic clinical features. Various microbial agents were implicated in the causation of RA. Extensive literature based on the results of various genetic, microbiological, molecular, and immunological studies carried out by independent research groups supports the role of Proteus mirabilis bacteria in the etiopathogenesis of RA. New diagnostic markers and criteria and the use of a novel therapeutic protocol in the form of antibiotic and dietary measures are suggested to be used together with current treatments in the management of RA. Prospective longitudinal studies with the use of antimicrobial measures in patients with RA are required to establish the therapeutic benefit of this microbe-disease association.

The potential use of antibacterial peptide antibody indices in the diagnosis of rheumatoid arthritis and ankylosing spondylitis

BACKGROUND

Both rheumatoid arthritis (RA) and ankylosing spondylitis (AS) are potentially disabling arthritic disorders for which as yet no highly sensitive and reliable diagnostic laboratory markers are available.

OBJECTIVE

The objective of this study was to evaluate the levels of antibodies against Proteus and Klebsiella antigenic peptides in an endeavor to develop diagnostic indices for the identification of patients with RA and AS, respectively.

METHODS

Sera from 50 patients with RA, 34 patients with AS, and 38 healthy subjects were screened for antibodies against "ESRRAL" and "IRRET" synthetic amino acid peptides obtained from Proteus hemolysin and urease (HU) as well as against "QTDRED" and "DRDE" peptides from Klebsiella nitrogenase and pullulanase (NP) proteins, respectively. Multiplication of the 2 antibodies against each organism produced indices for RA-HU and AS-NP.

RESULTS

Significantly increased levels of anti-HU antibodies (P<0.0001) were observed in patients with RA when compared with patients with AS or with healthy control subjects. Patients with AS were found to have significantly elevated levels of anti-NP (P<0.0001) antibodies when compared with patients with RA or with healthy subjects. Furthermore, all patients with RA were found to have values of anti-HU antibody (RA-HU) index above 95% confidence limit (CL) of the mean of healthy control subjects; meanwhile, all patients with AS were having values of anti-NP antibody (AS-NP) index above the 95% CL of the mean of healthy control subjects (100% sensitivity). However, the specificity of the RA-HU index in RA and the AS-NP index in patients with AS were 92% and 95%, respectively.

CONCLUSION

The use of the RA-HU or AS-NP diagnostic index as a sole marker or in combination with other autoantibody markers could be used in the identification of patients with RA or AS, respectively. Longitudinal investigations starting with patients with early disease will be needed.

Relative predispositional effects and mode of inheritance of HLA-DRB1 alleles among community-based Caucasian females with rheumatoid arthritis

Multiple HLA-DRB1 alleles encoding a shared epitope (SE) at amino acid positions 70-74 are associated with susceptibility to rheumatoid arthritis (RA). However, the nature of the association and the mode of inheritance differ depending upon the source of RA patients and laboratory methodology. We studied the relative predispositional effects (RPE) and mode of inheritance of DRB1 alleles among a community-based sample of 180 RA patients and 116 healthy controls, all Caucasian females. Polymerase chain reaction (PCR)-based assays were used for DRB1 genotyping, and the genotypic distributions were analyzed by both the RPE and antigen genotype frequency among patients (AGFAP) methods. We examined the evidence of synergy among DRB1 alleles for RA risk by comparing the observed DRB1 genotype distribution to that predicted under Hardy-Weinberg equilibrium. Fifty-six percent of RA cases were attributable to DRB1 alleles encoding the SE. The RPEs of DRB1 alleles were *0401 > *0404 > *1001 > *0408 > *0101. The strength of the RA association was not significantly different for these alleles. The AGFAP analysis was consistent with a recessive mode of inheritance for DRB alleles, while an additive (dominant) model was rejected. We found no evidence of synergy for RA risk among individual DRB1 alleles based on comparison of the observed vs. predicted genotype distributions. These results suggest that among community-based Caucasian females with RA, the DRB1 RA susceptibility gene influences disease risk in a recessive fashion without synergy among individual DRB1 alleles.

HLA haplotype sharing in rheumatoid arthritis sibships: risk estimates subdivided by proband genotype

There is a well-known association between rheumatoid arthritis (RA) and HLA-DR4. Recent research has indicated that both DR4 haplotypes are important in disease predisposition (favoring a recessive mode of inheritance). Others have suggested that certain combinations of genotypes, in particular Dw4/Dw14 heterozygotes, may be more important than others. We examined the mode of inheritance of RA using data from the Arthritis and Rheumatism Council's national repository of family material [Worthington et al. (1994) Br J Rheumatol 33:970-976]. There were 85 affected sibships consisting of 77 sib pairs, 6 trios, 1 quintuplet, and 1 sextuplet. The affected sibs shared two, one, and zero parental HLA haplotypes in a ratio of 0.42:0.43:0.15, which was significantly different from random expectations (P = 0.00009). Risk estimates for RA to sibs were calculated based on an overall sibling recurrence risk of 3.9%. Risks for those sharing two, one, and zero parental HLA haplotypes were 6.5% [95% confidence interval (CI) = 5.1-7.9%], 3.3% (95% CI = 2.6-4.0%), and 2.5% (95% CI = 1.5-3.5%), respectively. We also examined the risk of RA based on the DRbeta1 genotype status of sib and proband. After excluding genotypic combinations with small numbers, the highest genotype-specific risks were seen for sibs sharing two haplotypes with either a DRbeta1*0401/DRbeta1*0404 (12.5%, 95% CI = 6.9-15.2%) or a DRbeta1*0401/DRbeta1*0408 (11.1%, 95% CI = 4.5-15.1%) proband. An independent assessment based on the AGFAP methodology confirmed the increase in risk for these genotypes, in particular for DRbeta1*0401/DRbeta1*0408. The excess being due to *0401/*0408 rather than to *0401/*0404 may explain why the Dw4/Dw14 effect is not always observed.

Felty syndrome complicating juvenile rheumatoid arthritis

PURPOSE

To describe a case of Felty syndrome (FS) in a child with (JRA) and review the previous literature on this rare entity.

METHODS

Review of clinical data including results of serial blood counts, bone marrow aspirate, human leukocyte antigen (HLA)-typing, and abdominal sonography.

RESULTS

Serial blood counts over 2 years revealed persistent leukopenia and thrombocytopenia. Bone marrow aspirate showed normal trilineage hematopoiesis, abdominal sonography demonstrated an enlarged spleen, but normal liver and portal circulation. HLA-typing was most significant for positivity of the DR 1 allele.

CONCLUSION

This is only the third child, and the first preadolescent, to be reported with FS complicating juvenile rheumatoid arthritis. This condition needs to be considered in the differential diagnosis when leukopenia, thrombocytopenia, or both develop in patients with JRA.

The genotypic distribution of shared-epitope DRB1 alleles suggests a recessive mode of inheritance of the rheumatoid arthritis disease-susceptibility gene

OBJECTIVE

To test whether the genotypic distribution of rheumatoid arthritis (RA)-associated DRB1 alleles suggests that the DRB1-associated disease-susceptibility gene has a recessive or additive (dominant) mode of inheritance.

METHODS

Caucasian patients with RA and control subjects were recruited from a faculty outpatient practice. DRB1 typing was done by several DNA-based techniques: polymerase chain reaction (PCR), followed by dot-blot hybridization with sequence-specific oligonucleotides, conventional and PCR-based restriction fragment length polymorphisms (RFLPs), and a multiplex amplification-refractory mutation RFLP system. The genotypic distribution of shared-epitope DRB1 alleles was analyzed by antigen genotype frequency among patients. The analytical method postulates a linkage-disequilibrium model with a disease locus close to a marker locus and a marker allele in linkage disequilibrium with the disease-susceptibility allele. In this instance, the marker allele was defined alternatively by any DR4-group allele, by any DR4-group or DR1-group allele, by any DR4-group shared-epitope allele, by any DR4-group shared-epitope allele plus DRB1*0101, or by any shared-epitope DRB1 allele. Observed numbers were compared with those predicted for recessive mode or additive (dominant) mode of inheritance of the DRB1-associated RA disease-susceptibility gene.

RESULTS

The genotypic distribution of shared-epitope DRB1 alleles (DRB1*0401, *0404, *0405, *0408, *0101, *0102, or *1001) fit that predicted for a recessive mode of inheritance and was significantly different from that predicted for an additive (dominant) mode. When the analysis was restricted to shared-epitope DR4 alleles alone (DRB1*0401, *0404, *0405, or *0408), the observed genotype numbers fit the recessive mode best. When DR1-group alleles were added to DR4-group alleles, or alternatively, when the major shared-epitope DR1 allele (*0101) was added to DR4-group shared-epitope alleles, there was a less significant deviation from the additive mode of inheritance. The reason for this was derived by comparison of observed genotype frequencies to those expected under Hardy-Weinberg equilibrium; there was a deficit of persons with DRB1*0401, *0101 and an excess of *0101,X.

CONCLUSION

The genotypic distribution of shared-epitope DRB1 marker alleles suggests that the mode of inheritance of the DRB1-associated disease susceptibility gene must be recessive and not additive (dominant).

The role of T cell receptor beta chain genes in susceptibility to rheumatoid arthritis

OBJECTIVE

To evaluate the role of the T cell receptor beta chain locus (TCRB) in genetic susceptibility to rheumatoid arthritis (RA).

METHODS

Twenty-eight multiplex RA families were recruited from 3 rheumatology outpatient departments. All members were genotyped for a highly informative microsatellite (V beta 6.7), a V beta 12.2 SSCP marker, and a biallelic C beta restriction fragment length polymorphism. Data were analyzed by the SIBPAL program to assess identity-by-descent in affected sib-pairs.

RESULTS

Using the V beta 12.2 marker, there was suggestive evidence of increased sib-pair sharing (P = 0.005) in affected offspring (a P value of 0.001 is generally taken to establish linkage). Data for V beta 6.7 and C beta yielded significance levels of 0.06 and 0.19, respectively.

CONCLUSION

These data suggest that a gene in or linked to the TCRB complex may confer genetic susceptibility to RA in these families. Confirmation in a larger panel of families is required.

HLA class II and T-cell receptor beta chain polymorphisms in Belgian patients with rheumatoid arthritis: no evidence for disease association with the TCRBC2, TCRBV8 and TCRBV11 polymorphisms

OBJECTIVES

To investigate whether T-cell receptor (TCR) beta chain germline alleles, either alone or in combination with a particular HLA-genotype, are associated with rheumatoid arthritis (RA).

METHODS

Three restriction fragment length polymorphisms (RFLPs), detected with TCR constant (TCRBC2) and variable (TCRBV8, TCRBV11) gene segments were analysed in a representative group of Belgian, HLA class II-typed patients with RA, and in a group of Belgian control subjects.

RESULTS

The study confirmed the known association of RA with the HLA-DRB1*0401/0404 genotype (RR = 2.14, 95% CI = 1.16-4.00) in the Belgian RA population. This association was even more pronounced in the patients with more severe RA (RR = 3.26, 95% CI = 1.55-6.89). These data suggest that the HLA-DRB1*04 genotype can be used as a marker for disease severity. Similar frequencies in patients and controls were observed for all TCRB RFLPs studied, and this was in spite of subgrouping the RA population according to criteria for disease stratification.

CONCLUSION

While a clear association with HLA DRB1*0401/0404 is observed, no interactive effects were seen with RA, DR4, TCRBC2 and TCRBV alleles, implying that the combined presence of these polymorphic markers does not cause an increased susceptibility to RA, and does not predispose for more aggressive RA, nor for familial aggregation of the disease. These results argue against the hypothesis that TCRB polymorphisms play a crucial role in the susceptibility for RA.

Local anti-type II collagen antibody production in rheumatoid arthritis synovial fluid. Evidence for an HLA-DR4-restricted IgG response

OBJECTIVE

To investigate the production of type II collagen (CII) antibodies in the synovial fluid (SF) of rheumatoid arthritis (RA) patients, and to examine the HLA dependence of this local production.

METHODS

The ELISPOT method was used for enumerating anti-CII-reactive cells. Serologic tissue typing was performed.

RESULTS

Anti-CII-reactive cells were found in the SF of 16 of 31 patients, but not in any of the peripheral blood samples obtained in parallel. SF anti-CII antibody production showed no correlation with clinical parameters, but its frequency increased significantly with age. The IgG anti-CII response occurred exclusively in patients who were positive for HLA-DR4 and was significantly associated with DR4.

CONCLUSION

Anti-CII production may be important in local immune complex formation. The indirect demonstration of a DR4-restricted T cell response to CII is an indication of a pathogenetic role of collagen autoimmunity in RA.

Amino acids in the peptide-binding groove influence an antibody-defined, disease-associated HLA-DR epitope

A shared amino-acid sequence on the alpha helix of certain DR beta 1 chains is predicted to generate a 'shared epitope' that is implicated in susceptibility to the development of rheumatoid arthritis (RA). Different relative risks (RR) for disease susceptibility and severity conferred by these DR beta 1 chains suggest that their 'shared epitopes' are not equivalent. A set of monoclonal antibodies (MoAb) that map to the critical region, and for which optimal binding depends on DR context and cell lineage, was used to test this idea. Mapping experiments using mutated DR beta 1* molecules showed that the antibody-binding epitopes are overlapping; residue 70Q is pivotal for each, but neighbouring residues on the alpha helix and on the floor of the groove are also involved. Importantly, these epitopes are profoundly modified by peptide loading of DR beta 1*0401 molecules. These data suggest that 'shared epitopes' on DR molecules that are associated with RA are influenced by their context; such structural modifications may be the basis for the varying susceptibilities conferred by these DR molecules for the development of RA.

T-cell antigen receptors in rheumatoid arthritis

Rheumatoid arthritis (RA) is a systemic disease of unknown etiology characterized by chronic inflammation mainly in the joints. Several lines of evidence suggest that T cells are involved in the pathogenesis of the disease. RA is associated with certain HLA-DR alleles. Studies analyzing T-cell receptor transcripts in RA have found biased or preferential usage of certain V alpha and/or V beta gene segments by T cells infiltrating the synovial membrane or extravasating into the synovial fluid compared to peripheral blood. In certain patients few T-cell antigen receptor (TCR) clones dominated the infiltrating T cells, suggesting that T cells from the synovial membrane or the synovial fluid comprise oligoclonal populations of T cells. However, other studies have found a polyclonal population of T cells. In interpreting these results the phase of the disease (early vs. late RA), the source of T cells and the limitations of the methods used in these studies should be taken into consideration. However, it appears that synovial T cells comprise oligoclonal populations of T cells and that there is a bias towards particular TCR gene segments, although a specific TCR gene segment in RA has not emerged.

Lack of association of T cell receptor V beta 8 polymorphism with rheumatoid arthritis in United Kingdom and Italian white patients

OBJECTIVES

To study if the reported association of a BamH I 2kb RFLP of the T cell receptor V beta 8 gene with DR4+ rheumatoid arthritis patients is found in non-American white populations.

METHODS

The frequency of this RFLP in two different populations was analysed. Eighty one northern Italians were studied for HLA-DR genotypes and V beta 8 polymorphism, and 29 DR4+ British white patients were studied for V beta 8 polymorphism.

RESULTS

No association between the V beta 8 RFLP and DR4 was found with rheumatoid arthritis in both groups.

CONCLUSION

The reported V beta 8-DR4 association is not generally applicable. The lack of association in our populations may be due to genetic differences, or to differences in factors which shaped the T cell repertoire.

Resistance to collagen-induced arthritis in rats and rhesus monkeys after immunization with attenuated type II collagen

Immunization of susceptible rodent or primate species with type II collagen (b-CII) from bovine origin induces type II collagen-induced arthritis (CIA). The disease is characterized as a systemic polyarthritis associated with humoral and cellular autoimmunity to CII and shares similarity with human arthritic diseases. The objective of this study was to develop a procedure for induction of resistance to CIA in animals, which possess a certain major histocompatibility complex phenotype that makes them prone to develop CIA (susceptible). It is shown that by immunization with an attenuated form of CII, in which arthritogenic epitopes have been destroyed by heat denaturation, disease resistance is induced in a susceptible inbred rat strain (RT-1u) and in an outbred population of susceptible rhesus monkeys (lacking the Mamu-A26 allele). In both species the disease resistance is connected with modulation of anti-CII autoantibodies of the IgM isotype. This protocol may provide a basis for effective and safe methods to induce protection to autoimmune arthritis in those subjects that are genetically prone to develop such a disease.

Epistatic modeling in rheumatoid arthritis: an application of the Risch theory

Rheumatoid arthritis (RA) is a disease of unknown etiology but with a presumed complex pattern of inheritance. Risch [Am J Hum Genet 46:222-228, 1990] has shown that the recurrence risk ratio, lambda R, (which is defined as the risk to type R relatives vs. the population prevalence) can be used to evaluate patterns of inheritance in genetically complex diseases. We have used the Risch theory to examine some multiple locus models of inheritance in RA. Recurrence risk ratios in MZ twins and in 1st, 2nd, and 3rd degree relatives are summarized from the literature. The limited data available supports at least a two-locus model of inheritance for RA (assuming that one locus is HLA). Better estimates of the recurrence risk ratios in RA families are required so that the Risch theory can be pursued further.

AGFAP method: applicability under different ascertainment schemes and a parental contributions test

The antigen/allele genotype frequencies among patients (AGFAP) method has been powerful in discriminating between modes of inheritance, and detecting heterogeneity effects, for a number of diseases associated with the HLA system. The method is not dependent on the high level of polymorphism seen in the HLA system, but does require a marker allele association with disease. With recent rapid advances in mapping of the human genome, the method is increasingly relevant in all disease studies. Extension of the AGFAP method to ascertainment schemes other than random sampling of patients is presented here. The method is shown to be robust for distinguishing between incompletely penetrant recessive vs. additive or dominant models if affected children are obtained from nuclear families selected on the basis of at least two affected members: two affected sibs, or an affected parent and affected child. The method can lead to false conclusions for data from families ascertained for at least one affected parent and two affected children. A new test, termed the parental contributions test, applicable in families selected for the presence of an affected parent, and one or more affected children, is presented. The test, based on the expected symmetry (recessive) vs. asymmetry (additive and dominant) of parental marker allele contributions to an affected offspring in these pedigrees, is powerful in distinguishing between these modes of inheritance when there is a marker allele association with disease. Sporadic cases of disease are shown to cause deviations from AGFAP expectations for the recessive model, but not for the additive model. These results will aid in study of the genetics, and hence molecular basis, of complex diseases.

Non-MHC-linked genes in autoimmune diseases

The gene responsible for the lpr mutation in MRL mice that are prone to systemic lupus erythematosus has been shown to encode the apoptosis-inducing Fas antigen, thus pointing to control of apoptosis as a major regulatory mechanism in autoimmunity. In the non-obese diabetic mouse model for insulin-dependent diabetes, four non-MHC-linked loci have been localized in the murine genome that were found to be associated with successive stages of the disease. These findings should soon have a major impact on our understanding of human autoimmune diseases.