Association of MHC antigens with susceptibility to and severity of rheumatoid arthritis in multicase families

Respiratory symptoms in rheumatoid arthritis: relation to pulmonary abnormalities detected by high-resolution CT and pulmonary functional testing

Pulmonary disease is the most frequent and among the most severe extra-articular manifestation of rheumatoid arthritis (RA). However, this issue has not been sufficiently studied in Egyptian patients. The objectives of the present study are to investigate the prevalence and types of pulmonary involvement using high-resolution computed tomography scan (HRCT) and pulmonary function tests (PFT) and evaluate the association between respiratory symptoms and RA-lung disease in a group of Egyptian RA patients. Thirty-six RA patients were recruited; 34 females (94.4%) and 2 males (5.6%) with median age of 48.5 years, and none of them was smoker. Detailed medical and drug histories were obtained. PFT, plain X-ray of the chest, and HRCT were performed to all subjects involved. Nearly 64% of RA patients demonstrated abnormalities in PFT and 47% in HRCT. Mixed restrictive and obstructive pattern was the commonest. Nearly two-thirds of our patients reported one or more pulmonary symptom whether dyspnea, cough, wheezing, or phlegm. Dyspnea was the most frequent symptom. Respiratory symptoms were statistically more common in patients with lung disease. The advanced age, high radiological score, and severity of rheumatoid disease were found to be predictive of lung involvement. Among respiratory symptoms, dyspnea and cough were associated with any pulmonary abnormalities. When specific pulmonary abnormalities were considered, only dyspnea was identified as predictor for restriction. For obstructive abnormality, both cough and wheezing provided valid prediction. We conclude that pulmonary involvement is a common manifestation in Egyptian RA patients, and the pattern of involvement is generally consistent with other studies that were performed worldwide. Specific respiratory symptoms could be used as practical, easy, and cost-effective method, especially in older and with more severe RA patients, to discriminate patients in need of subsequent PFT and HRCT imaging.

Specific autoantibodies precede the symptoms of rheumatoid arthritis: a study of serial measurements in blood donors

OBJECTIVE

Autoantibodies have been demonstrated in single serum samples from healthy subjects up to 10 years before they developed rheumatoid arthritis (RA). However, the time course for the development of antibodies before onset of clinical RA is unknown, nor is it known which antibody, or combinations of antibodies, might be most sensitive or specific for predicting future development of the disease. The present study was undertaken to investigate this.

METHODS

Patients with RA who had been blood donors before the onset of disease symptoms were enrolled. Frozen serum samples from each donor were retrieved, together with 2 serum samples from controls matched for age, sex, and date of donation. All samples were tested for IgM rheumatoid factor (IgM-RF) and anti-cyclic citrullinated peptide (anti-CCP) antibodies.

RESULTS

Seventy-nine patients with RA (62% female; mean age at onset of symptoms 51 years) were included. A median of 13 samples (range 1-51) per patient were available; the earliest samples had been collected a median of 7.5 years (range 0.1-14.5) before the onset of symptoms. Thirty-nine patients (49%) were positive for IgM-RF and/or anti-CCP on at least one occasion before the development of RA symptoms, a median of 4.5 years (range 0.1-13.8) before symptom onset. Of the 2,138 control samples, 1.1% were positive for IgM-RF, and 0.6% were positive for anti-CCP.

CONCLUSION

Approximately half of patients with RA have specific serologic abnormalities several years before the onset of symptoms. A finding of an elevated serum level of IgM-RF or anti-CCP in a healthy individual implies a high risk for the development of RA. We conclude that IgM-RF and anti-CCP testing with appropriately high specificity may assist in the early detection of RA in high-risk populations.

Familial vs sporadic rheumatoid arthritis (RA). A prospective study in an early RA inception cohort

OBJECTIVES

To study potential differences in demographic, process and outcome variables between familial and sporadic rheumatoid arthritis (RA) in an early RA inception cohort.

METHODS

In 1998, we ascertained the familial status of all collaborative patients in a large early RA inception cohort at our department. Familial RA was defined by the presence of at least two siblings fulfilling the American College of Rheumatology criteria for RA. Baseline demographic data and prospectively recorded disease activity variables, therapies and radiological damage during the first 6 yr of disease were included in the analysis. A regression analysis was performed to assess whether familial clustering is a prognostic factor.

RESULTS

We identified 142 patients with sporadic and 36 with familial RA. The most striking difference between these groups was the larger sibship size in multicase families (8.2 +/- 2.5 vs 5. 5 +/- 2.8; P < 0.0001). Age at onset was similar in both groups, although males with familiar RA were younger at disease onset than those with sporadic RA (median 50 vs 57 yr; P=0.03). No differences were found in gender, presence of rheumatoid factor (RF), antinuclear factor and HLA-DR typing or in disease activity, interventions and outcome over 6 yr of follow-up. Early radiological damage and disease activity, but not familial history of RA were prognostic for X-ray damage.

CONCLUSION

We show that sibship size is the only relevant risk factor for familial RA. No differences in genotypic and phenotypic characteristics, disease severity or radiological damage were observed among familial and sporadic RA. Familial history of RA is not a poor prognostic factor. This prospective study confirms previous cross-sectional findings in the Dutch population.

HLA markers and prediction of clinical course and outcome in rheumatoid arthritis

OBJECTIVE

To evaluate HLA markers as early prognostic factors for disease severity in rheumatoid arthritis (RA).

METHODS

HLA genotyping was carried out in a retrospective analysis of 66 RA patients and in a prospective study of 55 RA patients and 87 healthy controls using polymerase chain reaction-based methods for HLA-DRB1 specificities, DR4 alleles, and their linked DQB1 alleles, as well as HLA-B27. The clinical course of RA was assessed by clinical and radiologic scores. The impact of HLA markers was evaluated by epidemiologic means in addition to modeling using multiple logistic regression analysis.

RESULTS

Shared epitope-positive (HVR3+) DR4 alleles and the HVR3 amino acid cassette QKRAA were associated with RA in both longstanding (relative risk [RR] 3.34 and 3.19) and recent-onset (RR 2.1 and 2.37) RA. In longstanding RA, radiologic evidence of severe joint destruction (Larsen score > 1.62) was seen more often in HVR3 shared epitope-positive patients than in epitope-negative patients (odds ratio [OR] = 25.67, chi 2 = 13.59, P = 0.0003). Moreover, rank sum analysis of Larsen indices indicated significantly higher ranking for the presence of the RA-associated HVR3 cassettes (QKRAA, QRRAA) when expressed on a DR4 allele (P < 0.0001). In the prospective study, DR4-positive patients had a significantly increased risk (OR = 13.75, P = 0.00083) of developing bony erosions. In addition, HVR3 epitope-positive DR4-positive individuals had significantly higher Larsen indices than did epitope-negative patients (P = 0.0083). In particular, the presence of the HVR3 epitope on DR4 resulted in an increased a posteriori likelihood (0.91) of developing early erosive disease compared with an a priori risk of 0.62. Conversely, the likelihood decreased to a minimum of 0.35 when the HVR3 epitope was absent.

CONCLUSION

While the contribution of HLA typing to establishing the diagnosis of RA is limited, HLA-DR genotyping and DR4 subtype determination provide valuable markers for the prognosis of joint destruction in RA.

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).

Linkage of rheumatoid arthritis with HLA

OBJECTIVE

To determine whether HLA exerts a variable influence on the predisposition of siblings of probands with clinically mild and severe rheumatoid arthritis (RA).

METHOD

Calculation of crude and adjusted odds ratios for concordance rates in sibships sharing two, one and no HLA haplotypes with a proband with clinically mild and severe RA, and HLA haplotype sharing in multiply affected sibships in the same clinical groups.

RESULTS

Compared with a reference value of 1.0 in siblings sharing no HLA haplotypes with a proband with mild RA, siblings sharing two HLA haplotypes with a severely affected proband had a sibship concordance rate odds ratio of 9.7 (95% confidence interval 2.5 to 38.2). When adjusted for age, sex, and disease duration, the odds ratio was 7.6 (1.8 to 32.4). No other sibships showed concordance rates which were significantly higher than the reference group. HLA haplotype sharing in multiply affected sibships in which the proband had severe RA deviated significantly from random (two, one, and no HLA haplotypes shared: 53.3, 40, and 6.7%, respectively; expected 25, 50, and 25%), whereas in sibships of probands with mild RA they did not (14.6, 70.8, and 14.6%).

CONCLUSIONS

In the predisposition of siblings to RA, sharing HLA haplotypes with a proband is only important if the proband has severe RA. Mild RA is not genetically linked to the HLA region.

A T cell receptor beta chain variable region polymorphism associated with radiographic progression in rheumatoid arthritis

OBJECTIVE

In rheumatoid arthritis (RA) genetic factors influence susceptibility to disease and progression. Identifying these genetic factors may give more insight into the aetiology and pathogenesis of this disease. Furthermore, if these genetic markers can predict progression in an early stage of disease, timely institution of more aggressive treatment in patients with a bad prognosis may help to prevent joint damage. Several studies have shown that HLA-DRB1 alleles are associated with RA, whereas others have indicated that genes not linked to the HLA complex are also involved. Candidates for such genes are the T cell receptor (TCR) alpha/beta genes.

METHODS

The association of a polymorphism in a TCR beta chain variable region gene (TCR-V beta 8) with both risk for RA and radiographic progression of joint disease was analysed after a three year follow up. A cohort of 118 white patients with a duration of disease shorter than one year at entry, and 110 white controls were typed for this (BamHI) TCR-V beta 8 polymorphism.

RESULTS

The distribution of the two alleles, 2.0 and 23.0 kb, was identical in patients and controls. Radiographic progression (modified Sharp method) after a three year follow up, studied in 111 patients, was significantly less in the group possessing the 2.0 kb allele (p = 0.03).

CONCLUSION

This does not confirm the reported association of the (BamHI) TCR-V beta 8 2.0 kb allele with RA. By contrast with previous findings in smaller studies, in the present study this 2.0 kb allele was protective against radiographic progression. Because well known prognostic variables in RA were corrected for, the findings indicate that the TCR-V beta 8 polymorphism studied is a new prognostic marker for this disease.

P blood group phenotype, proteus antibody titres, and rheumatoid arthritis

The interrelationships between P blood group phenotype, proteus antibodies and rheumatoid arthritis (RA) were investigated in 140 patients with RA and 114 of their siblings who did not have RA. In the group with RA P2 subjects had significantly higher titres of proteus antibodies than P1 patients. This was not observed in the group without RA, or for antibodies to Escherichia coli. Although C reactive protein was the best predictor of proteus antibodies in the group with RA, the P blood group had an independent and significant influence. These observations suggest a testable model in which asymptomatic carriage of proteus in the urinary tract may lead to antibody production, which in turn may be important in the pathogenesis of RA.

Influence of the severity of rheumatoid arthritis on sex differences in health assessment questionnaire scores

In a study of 284 consecutive patients with rheumatoid arthritis attending hospital clinics a previous observation that female patients score higher on the Stanford Health Assessment Questionnaire (HAQ) than men was confirmed. A clinical disease severity score and the spread/severity index also showed that women had more severe disease. Although scores in some categories of the HAQ were higher in women, they were not disproportionately so, providing no evidence that domestic categories of the HAQ are biased against women. A multiple regression analysis showed that the spread/severity index score was the best predictor of HAQ scores, with sex making no significant contribution. The severity of the disease adequately explained the higher HAQ scores in female patients with rheumatoid arthritis.

Strong primary selection for the Dw4 subtype of DR4 accounts for the HLA-DQw7 association with Felty's syndrome

Felty's syndrome (FS) is a rare complication of rheumatoid arthritis (RA) previously shown to be strongly associated with HLA-DR4 and less significantly with HLA-DQw7. To map more precisely the HLA locus responsible for susceptibility to FS, we have examined HLA-DR4 and DQ beta-chain polymorphisms in FS patients and controls using restriction fragment length polymorphism analysis and polymerase chain reaction amplification in conjunction with oligonucleotide probing. The increased frequency of DR4 in FS (93% vs. 32% controls) was due almost entirely to enrichment for the Dw4 subtype (88% vs. 20% controls) with a secondary increase of the Dw14 subtype. Dw10 and Dw13 subtypes of DR4 were absent from the patient group. Increase in DQw7 frequency among DR4 FS patients could be accounted for by linkage disequilibrium between Dw4 and DQw7 alleles. Whereas susceptibility to RA is strongly associated with a conserved HLA-DR beta epitope associated with several DRB1 alleles, it is primarily the Dw4 allele which is associated with progression to Felty's syndrome. The finding that amino acid sequence variation at the DR4B1 locus rather than DQB1 is associated with development of FS will have important implications for the development of novel immunotherapies which are major histocompatibility complex allele-dependent.

HLA typing in families with multiple cases of rheumatoid arthritis

Thirty one white patients from 14 families with multiple cases of rheumatoid arthritis (RA) and 42 of their healthy relatives were completely HLA typed. In contrast with class I antigens, the class II antigens DR1 and DR4 were significantly more common in the patients than in a group of 200 healthy local white controls (DR1: 32% v 12%; DR4: 48% v 28%, in patients and controls respectively). Owing to the small number of cases the data from this study were combined with those of published reports. Examination of patients for DR1 and DR4 homozygosity and DR1/4 heterozygosity showed an increase of DR1 homozygous patients, which was not statistically significant. There was no striking deviation from random expectation in haplotype sharing of affected sib pairs. These results are compatible with a dominant influence of DR1 and DR4 in the mode of inheritance. The nearly random haplotype sharing and the molecular relation between DR1 and DR4 support the hypothesis of a direct influence of these antigens in the pathogenesis of RA. Only 68% of the patients in this study possessed either DR1 or DR4, possibly indicating a subtype of RA which is independent of HLA. Clinical and serological variables were measured and indicated no significant difference between DR1 (or DR4) positive and DR1 (or DR4) negative disease. In this small group of patients the clinical course of RA seemed to be determined mainly by other genetic or environmental factors.

DR4 prevalence related to the age at disease onset in female patients with rheumatoid arthritis

The prevalence of HLA-DR4 in relation to age at disease onset was calculated in 226 consecutive female patients with definite or classical rheumatoid arthritis (RA). A slight increase in the prevalence of DR4 with age at RA onset was found. This appeared to be due to the low percentage of rheumatoid factor (RF) positivity in the youngest age groups; the DR4 prevalence in the RF positive patients was constant for all decades--that is, approximately 60%. A previously reported declining trend of DR4 prevalence in women with RA in relation to age of RA onset may be due to the disease heterogeneity of the patients included in that study.

Influence of prognostic features on the final outcome in rheumatoid arthritis: a review of the literature

The literature on prognostic features on the final outcome in RA is reviewed. It is generally agreed that female sex and a positive RF are variables indicating a poor prognosis. Longstanding increased ESR and CRP values, decreased Hb, or the appearance of subcutaneous nodules are indicators of a less favorable clinical course. No conclusions can be drawn regarding other factors due to the incomplete and heterogeneous study designs.

Linkage studies of HLA and rheumatoid arthritis in multicase families

The linkage of rheumatoid arthritis (RA) to the HLA-DR locus was investigated in 17 families with multiple cases of RA. Log odds scores were computed using the Liped program; sibship associations were examined by 2 methods. The results showed a trend toward linkage which was short of significance. The results were similar for patients with classic or definite RA, with or without the inclusion of probable RA patients. The finding of strong association and weak linkage would suggest that it is DR4, itself, that is important in RA.

Rheumatoid factor tests in the diagnosis and prediction of rheumatoid arthritis

Four assays of rheumatoid factor (RF) have been measured on serum from 213 individuals from 13 families containing at least two sufferers from classical or definite rheumatoid arthritis (RA). Families were not uniformly RF positive or negative, and there was no evidence that non-RA RF positivity was inherited. Four individuals developed definite RA over a two year period, showing that the family members were at increased risk of RA. IgG RF and latex RF assays predicted the RA in the four cases. An association of RF positivity in RA with DR4 was observed, but this may be related to disease severity.

Characteristics of cellular immune responses to collagen type I or collagen type II

We have examined the murine cell-mediated immune (CMI) response to collagens type I (CI) and type II (CII) as measured by in vivo delayed-type hypersensitivity responses. We have verified the histopathology and kinetics of the cell-mediated immune responses. Predominant cell-mediated responses were obtained 7, 10, or 14 days following immunization. A presumed antibody-mediated reaction was observed at later times (e.g., greater than 21 days following immunization). The CMI responses to the collagens show a strain-dependent relationship. For CI, the CMI response profile shows H-2b greater than or equal to H-2k = H-2q much greater than H-2d. For bovine CII, the response profile is H-2d greater than H-2b = H-2k = H-2q; the chick CII response profile is H-2q = H-2k greater than H-2b = H-2d, and in limited testing, only the H-2q strain could generate murine CII-specific cell-mediated immune responses. The CII-specific CMI response is cross-reactive with CII from several species of animals, but not with CI. Further, the collagen-specific CMI response can be elicited with certain cyanogen-bromide fragments of bovine CII. Finally, our study also demonstrates that there is a non-H-2-linked locus(i) involved in the development of CII-induced arthritis.

Occurrence of autoimmune diseases and autoantibodies in multicase rheumatoid arthritis families

The presence of autoimmune diseases and autoantibodies has been studied in 237 individuals from 17 families with two or more members affected by rheumatoid arthritis (RA). Hyperthyroidism occurred significantly more frequently than in a local control population (p less than 0.05), but if the RA cases were excluded this significance was lost. Thyroid cytoplasmic and microsomal antibodies were significantly more common (p less than 0.001), and this remained true if RA sufferers were excluded (p less than 0.01). The prevalence of both clinical thyroid disease and circulating thyroid autoantibodies was similar in the families where RA was associated with HLA-DR4 and in those where no DR4 association was observed. RA and immune thyroid disease may, therefore, share a common inherited factor, but this is unlikely to be at the HLA-DR locus. Antinuclear factor (ANF) was found in association with RA and with HLA-DR3 within the RA group (p less than 0.02). Relatives of RA sufferers did not show any excess of ANF positivity. The prevalence of pernicious anaemia (PA) and gastric parietal cell antibody did not differ from the expected.