Association of HLA-DRw4 with rheumatoid arthritis in black and white patients

The shared epitope and severity of rheumatoid arthritis

After two decades of research involving thousands of RA patients, it is still not possible to precisely define the relation of HLA-DRB1 SE alleles to RA severity. Improvements in our understanding require more careful consideration of several factors such as ethnicity, gender, and the specific SE allele and genotype inherited. Large studies of heterogeneous groups of patients are required and indicate the need for collaborative efforts among researchers. In the interim, meta-analysis of the existing literature may provide some insight, because it allows utilization of the tremendous amount of research already completed. A preliminary meta-analysis highlighted the significant heterogeneity among the existing literature, and a more ambitious meta-analysis that uses individual patient-level data is currently ongoing. Profound implications exist for determination of the precise relationship between the SE and RA severity. This information could be valuable in identifying patients at greater risk of severe complications or as a stratification variable for clinical trials. Moreover, patients genetically predisposed to severe disease may benefit from early initiation of more aggressive therapy. Ultimately, clarification of the role of the SE may be valuable for the development of specific therapies directed toward DRB1 and related targets.

Genetic influences on rheumatoid arthritis in African Americans

Rheumatoid arthritis is a common autoimmune disease characterized by inflammation of the synovial membrane of diarthrodial joints, which often leads to joint damage and disability. There are known associations between major histocompatibility complex class II alleles and susceptibility to rheumatoid arthritis and its severity in Caucasians. African Americans, an admixed population in the United States, has been underrepresented in genetic studies of the susceptibility and severity of rheumatoid arthritis. With the advent of biologic agents, which target specific molecules of the immune system (e.g., tumor necrosis factor, interleukin-1), biologic markers of treatment response in Caucasians and in African Americans would be clinically useful.

HLA-DRB1*01 and DRB1*04 alleles in Sardinian rheumatoid arthritis patients

In Sardinia, like in other Caucasoid populations, rheumatoid arthritis (RA) is significantly associated with HLA-DR4 and DR1 antigens. To discover which DR4 and DR1 alleles were associated with the disease we selected 22 Sardinian patients affected by RA. Fifty DR4+ and 28 DR1+ healthy individuals coming from the same geographical area were used as controls. In the Sardinian patients only two DRB1*04 alleles were observed: DRB1*0405 in 11 and DRB1*0403 in three patients. The DRB1*0102 allele was observed in two patients and DRB1*0101 in six patients. Hereditary predisposition to RA in Sardinia therefore seems to be almost exclusively associated with the DRB1*0405 and DRB1*0101 alleles which share the 67LLEQRRAA74-85VG86 epitope in the peptide binding groove.

Excess admixture proportion of extended major histocompatability complex haplotypes of Caucasian origin among rheumatoid arthritis associated haplotypes in African Americans and Afro-Caribbeans

Several extended major histocompatability complex (MHC) haplotypes are associated with susceptibility to autoimmune disease in Caucasian populations. It is known that African Americans and Afro-Caribbeans are ethnic groups descended from west, central and southern black African populations which are admixed with Caucasians. To examine the possible association of some marker of Caucasian MHC genes and susceptibility to rheumatoid arthritis (RA) in African Americans, we studied extended MHC haplotypes (HLA-B, complement and DR) in a sample of 18 African American and Afro-Caribbean probands with RA, their first degree relatives and in 15 non-RA families. We defined 36 disease-associated RA haplotypes among the probands and 96 normal haplotypes in normal individuals. To obtain the most conservative estimate, we excluded recognized Caucasian, DR4-bearing, extended MHC haplotypes from the analysis. Admixture proportions for non-HLA-DR4 extended MHC haplotypes of known Caucasian origin among RA-associated and normal haplotypes were computed (0.40 versus 0.163 respectively). When we compared the difference in proportions between RA and normal haplotypes, the proportion of extended MHC haplotypes of known Caucasian origin was significantly increased among RA-associated haplotypes (Z = 3.16, p (one sided) < 0.001, p (adjusted) < 0.008). Our results suggest that racial admixture with Caucasian MHC genes may augment RA susceptibility and thus may be one mechanism to explain the higher prevalence of RA in African Americans and Afro-Caribbeans than in black African populations.

Rheumatoid arthritis: pathogenesis and early recognition

Rheumatoid arthritis (RA) is a chronic, destructive disease characterized by joint pain and swelling, which progresses in a substantial percentage of patients to invasion of bone and cartilage. If not successfully treated, progressive joint destruction results in loss of function, disability, and increased mortality. The time from onset of symptoms to joint destruction is frequently measured in months rather than years. Unfortunately, the time from disease onset to diagnosis and initiation of effective therapy is often prolonged, allowing development of irreversible joint destruction. In order to apply current knowledge to reduce the disability and death associated with progressive RA, the clinician must understand the pathophysiologic stages of the disease as reflected in symptoms, radiography, and biochemical markers. Prognostic factors relevant to RA severity, including factors relevant to RA severity, including serum markers and genetic traits, must also be known so that appropriate therapeutic strategies can be planned. Although current therapy cannot reliably alter the long-term outcome of RA, new approaches are promising. Patients at high risk or who fail to respond to conservative therapy are candidates for earlier, more aggressive strategies using single or possibly combination antirheumatic therapy.

Anti-neutrophil cytoplasm antibodies (ANCA) in rheumatoid arthritis: relationship to HLA-DR phenotypes, rheumatoid factor, anti-nuclear antibodies and disease severity

To investigate a possible relationship between the presence of anti-neutrophil cytoplasm antibodies (ANCA), rheumatoid factors (RF), anti-nuclear antibodies (ANA), disease severity and HLA-DR phenotypes, 46 consecutive ANCA+ and 48 ANCA-, clinically well-documented RA patients were studied for RF, ANA and HLA-DR phenotypes. The 46 ANCA+ patients showed predominantly an atypical perinuclear staining pattern (89%). ANCA positivity was associated with higher RF titres (P < 0.005) and advanced functional Steinbrocker grades III/IV (P < 0.015). ANCA+ patients were also more often positive for ANA than ANCA- patients (P < 0.008). There was no correlation between ANCA positivity and certain HLA-DR phenotypes although the frequency of DR4+ (67% vs 52%) and, in particular, of DR4+ blanks (phenotypically homozygous) was increased in ANCA+ as compared to ANCA- patients (20% vs 8%). DR4-DR1-RA patients were twice as frequent in the ANCA- than in the ANCA+ group (22.9% vs 8.7%). Correspondingly, the DR4+DR1- phenotype was increased among ANCA+ RA patients. Regarding functional Steinbrocker grades, the DR4+ phenotypes were slightly but not significantly increased in grades III and IV whereas ANCA positivity was significantly associated with severe functional Steinbrocker grades III/IV (66% ANCA+ vs 39% ANCA-, P < 0.015). ANCA positivity identified a population of RA patients with a long-standing and severe clinical course of the disease. There was no correlation between ANCA positivity and certain HLA-DR phenotypes.

Elderly-onset rheumatoid arthritis

Elderly-onset rheumatoid arthritis (EORA), defined as rheumatoid arthritis (RA) with onset at age 60 years or over, differs slightly at presentation from younger-onset RA (YORA) by a more equal gender distribution, a higher frequency of acute onset with systemic features, more frequent involvement of the shoulder, and higher disease activity. Longitudinal studies have showed more disease activity, radiographic damage, and functional decline in patients with EORA than in those with YORA. These differences were only found in seropositive patients. Seropositive EORA was reported to be associated with HLA-DR4, in contrast to seronegative EORA. Possible heterogeneity in the pathogenesis of seronegative EORA is supported by the recognition of subsets that overlap with the clinical manifestations of other syndromes such as polymyalgia rheumatica and remitting seronegative symmetrical synovitis with pitting edema. In addition, crystal-induced arthritis and inflammatory osteoarthritis may be difficult to distinguish from EORA. The efficacy and toxicity of second-line drugs is similar in both age groups, but in the elderly caution is needed with the use of nonsteroidal antiinflammatory drugs and prednisone.

Coexistence of ochronosis and rheumatoid arthritis

We describe a 64-year-old female patient with ochronosis and rheumatoid arthritis. Magnetic resonance imaging of the spinal column disclosed the destruction of vertebral disks, and a bony bridging in Th12 to L2. In addition, we observed joint space narrowing in the wrists as well as among the carpal bones, positive rheumatoid factor and the presence of rheumatoid nodules, in which the histological findings were compatible with those of rheumatoid arthritis. The co-existence of these two diseases has not yet been previously reported. Pre-existing ochronotic arthropathy might have masked the manifestation of rheumatoid arthritis and made the diagnosis of rheumatoid arthritis rather difficult.

Arthritis and hypertension in patients with systemic lupus erythematosus

OBJECTIVE

The purpose of this study was to test the hypothesis that patients with systemic lupus erythematosus (SLE) who have, as part of their disease, persistent rheumatoid-like arthritis are less likely to be hypertensive than are other patients with SLE.

METHODS

A retrospective chart analysis of 662 patients with SLE seen in a university clinic was performed.

RESULTS

Data analysis revealed that hypertension and persistent arthritis were inversely correlated, particularly in those patients without nephritis and particularly in black patients.

CONCLUSION

We conclude that rheumatoid-like arthritis in patients with SLE is protective against hypertension, and speculate that this protection is conferred by a higher frequency of the DR4 allele.

Schizophrenia and rheumatoid arthritis: a review

Fourteen epidemiologic studies of the relationship of rheumatoid arthritis to schizophrenia have been conducted between 1934 and 1985. Twelve of the studies report a lower-than-expected rate of rheumatoid arthritis in populations of schizophrenics. Methodologic weaknesses in the studies are assessed. Nutritional, hormonal, psychosocial, genetic, and immunologic data and theories are briefly reviewed which might explain the epidemiologic results. There is sufficient evidence for the negative association between the two disorders to justify further research.

HLA and disease

Many human diseases are associated with HLA class I, class II and class III antigens. It appears that the class III antigen disease associations can be explained by a direct defect operating at the level of either the class III gene or its gene product. The mechanism underlying class I and class II antigen disease associations is at present unknown. In this review we have considered thirty diseases which have been ranked according to their relative risk as defined by the frequency of a given HLA antigen in patient and control populations. The chronic inflammatory disorder, ankylosing spondylitis and its association with HLA B27 has been used as a model to study the HLA linked diseases. We have suggested that the disease may be caused by the Gram-negative microorganism Klebsiella which has antigenic similarity to HLA B27. It is proposed that some antibodies made against Klebsiella bind to HLA B27, thereby acting as autoantibodies leading to the pathological sequelae of chronic inflammatory arthritis. This is the crosstolerance hypothesis or molecular mimicry model and it has been compared to the receptor model. It is further suggested that the crosstolerance hypothesis can be utilised as a general theory to explain the association of other diseases with the class I and class II antigens, and offer a possible explanation for the polymorphism of HLA.

Polymorphism of major histocompatibility complex extended haplotypes bearing HLA-DR3 in patients with rheumatoid arthritis with gold induced thrombocytopenia or proteinuria

The distribution of DR3 and of extended haplotypes bearing DR3 was studied in three groups of subjects: 35 patients with rheumatoid arthritis (RA) with gold induced thrombocytopenia or proteinuria, 185 patients with RA without these side effects, and 300 normal healthy controls. The extended haplotypes bearing DR3 were analysed with cDNA probes for DR alpha, DR beta, DQ alpha, and DQ beta genes. The data showed that the prevalence of DR3 was significantly higher in patients who developed gold induced thrombocytopenia or proteinuria than in normal controls or patients with RA without these side effects. Distribution of three extended haplotypes bearing DR3 (B8, DR3; B18,DR3; non-B8,non-B18,DR3) in patients with RA with thrombocytopenia or proteinuria was significantly different from that in normal controls, but not from that in patients with RA without these toxic reactions. Southern blot analysis of DR, DQ genes with cDNA probes showed that the extended haplotype bearing B8,DR3, which carries DQA2.1 and DQB2.1 genes, was present in a significantly higher proportion of patients with RA with gold induced thrombocytopenia or proteinuria (22/24, 92%) than in patients with RA without these side effects (32/45, 71%) or normal subjects (40/61, 66%). The data suggest that the genomic region on chromosome 6 involved in susceptibility to gold induced thrombocytopenia or proteinuria should be extended to the DQA2, DQB2 gene loci.

Association between HLA-DR antigens and rheumatoid arthritis in Arabs

Eighty five Arab patients with classical and definite rheumatoid arthritis were typed to determine the prevalence of HLA A, B, C, and DR antigens. A significant increase in the prevalence of HLA-A10, B8, B21, and DR3 was found in comparison with a control population matched for age and sex. HLA-DR5 was significantly decreased in the patient group. The classical association of HLA-DR4 with rheumatoid arthritis could not be confirmed in the Arab patients resident in Kuwait, supporting reported observations in different ethnic groups of associations with HLA antigens other than HLA-DR4 and indicating a heterogeneous genetic susceptibility to rheumatoid arthritis.

Reduction of the risk of rheumatoid arthritis among women who take oral contraceptives

Discrepant results among investigations of the association between oral contraceptive use and rheumatoid arthritis (RA) have been ascribed to shortcomings in the study methods. In the present study, we obtained detailed information on oral contraceptive use in 135 young women with confirmed definite or classic RA of recent onset and in 378 controls with soft tissue rheumatism or osteoarthritis. All patients had at least 2 years of followup to confirm the consistency of the diagnosis. Oral contraceptive use at any time before disease onset was reported by 70% of the RA patients and 85% of the controls; the latter figure corresponded to general population data for The Netherlands. This yielded a relative risk for RA of 0.39 among those who had ever used oral contraceptives and 0.58 for those using oral contraceptives at the time of symptom onset. The preventive effect of oral contraceptive use on the risk of RA was found to be independent of the dose, duration of use, or presence of HLA-DR4. The strongest protection was seen in women with a family history of RA and in women ages 31-40 at symptom onset. The conflicting results in the literature are discussed, and a possible biologic mechanism for this phenomenon is suggested.

Shared molecular markers of genetic predisposition to seropositive rheumatoid arthritis

Rheumatoid arthritis is associated with the human class II major histocompatibility complex antigens known as HLA-DR4. HLA-DR4 can be subdivided by cellular typing into five subtypes: Dw4, Dw10, Dw13, Dw14, and Dw15. By traditional serologic methods, 60-80% of rheumatoid arthritis patients type HLA-DR4 compared to approximately 20% of the general population. It has been demonstrated, using a panel of four alloreactive T-cell clones, each of which recognized HLA-DR4, Dw14 homozygous typing cells, that cells from all of a group of 23 rheumatoid arthritis patients could be recognized by one or more of these clones regardless of the patients' serologic typing. As the expressed polymorphism of the DR molecule is accounted for by the beta 1 gene, this gene was amplified, using the polymerase chain reaction, and sequenced. Seven patients whose cells were recognized by one of the DR4, DW14-specific T-cell clones, T431, were analyzed. All of these patients shared a common sequence in the third hypervariable region of the DR beta 1 chain gene. The sequence identified is the one normally associated with DR4, Dw14 and DR1. Patients and DR4-positive controls whose cells did not stimulate this clone did not share this sequence. These results suggest that this hypervariable region might be an important contribution to a restriction site for the putative causative agent(s) in rheumatoid arthritis.

Susceptibility epitope on HLA-DR beta chain for rheumatoid arthritis and the effect of the positivity on the clinical features

A highly significant association of an amino acid sequence, '70Q71R72R73A74A' located on the DR beta-1 chain, with rheumatoid arthritis (RA) was confirmed in Japanese patients using polymerase chain reaction. The '70QRRA74A' is the most plausible candidate of susceptibility epitope in Japanese RA patients. The patients carrying the sequence showed slightly higher but not significant familial incidence. The positivity of the 'QRRAA' showed no effect on the positivity of the rheumatoid factor, rheumatoid nodules, and extra-articular signs. Also no significant differences in other clinical parameters (ESR, CRP, Hb, A/G) and age at onset were observed regarding the positivity. The risk that the 'QRRAA' positive subjects would suffer from RA was estimated to be about 1.3% which meant 7.2 times easier to get RA than those without 'QRRAA'.

Putative amino acid sequence of HLA-DRB chain contributing to rheumatoid arthritis susceptibility

The association between HLA-DR4 and rheumatoid arthritis (RA) has been established in many ethnic groups. To clarify the determinant of susceptibility to RA, a polymorphic segment of the HLA-DRB gene was amplified in vitro by polymerase chain reaction and analyzed with oligonucleotide probes specific for the HLA-DR4 DNA sequences. A particular sequence encoding amino acids Gln70-Arg71-Arg72-Ala73-Ala74 showed a strong association with RA (p less than 0.005, relative risk 6.0). This amino acid sequence occurs in the DRB molecules with three RA-associated specificities, DR4/Dw14, DR4/Dw15, and DR1. DR4/Dw4, which is common in Caucasian RA patients, has a strikingly similar amino acid sequence Gln70-Lys71-Arg72-Ala73-Ala74 in terms of polarity and charge profiles. Other RA nonassociated sequences differ from this sequence by at least one amino acid substitution that causes the change of the net charge. The composition of amino acid residues at the positions 70-74 may play a crucial role in the pathogenesis of RA.

Association of complement alleles C4AQ0 and C4B5 with rheumatoid arthritis in Japanese patients

We investigated polymorphisms of complement components C2, C4, and factor B (BF) in Japanese patients with rheumatoid arthritis (RA). The frequencies of C4AQ0 (32.1%) and C4B5 (35.9%) among RA patients were significantly higher than among healthy control subjects. C4B5 was strongly associated with HLA-Bw54, Bw59, DR4.1, and DQw4. C4AQ0 showed no association with HLA-Bw54 or Bw59, but there was weak association with HLA-DR4.1 and DQw4. The number of persons with both C4AQ0 and C4B5 was significantly higher in the RA patient group (relative risk 13.5). C2C and BFS were the most common alleles in RA patients, as well as in healthy control subjects. These data support the existence of 2 different putative susceptibility haplotypes (HLA-Bw54 or Bw59;C2C; BFS;C4A3;C4B5;DR4.1;DQw4 and C2C;BFS; C4AQ0;C4B1 or C4B2) in Japanese patients with RA.

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.

HLA genes associated with rheumatoid arthritis. Identification of susceptibility alleles using specific oligonucleotide probes

We examined the association of individual HLA genes with rheumatoid arthritis (RA), using oligonucleotide probes that identified both DR4-associated and non-DR4-associated genes. Two distinct HLA-DR beta alleles (Dw4 and Dw14) were found in DR4+ RA patients compared with controls (Dw4 50% versus 17%; Dw14 35% versus 5%; total DR4 73% versus 30%), indicating that these 2 alleles are independent susceptibility genes. Remarkably, the majority of the DR4- RA patients also demonstrated a linear DNA sequence, apparently "shuffled" between different susceptibility alleles, identified with an oligonucleotide probe to a key portion of the Dw14 gene.

A new look at the shared epitope hypothesis

The striking correlation observed between T cell recognition and the sharing of the DR-beta-1 gene sequences (position 67-74) among patients with rheumatoid arthritis studied suggests that the third hypervariable region might be an important contribution to one restriction site for the putative causative agent(s) in rheumatoid arthritis. The fact that this sequence was found in DR1, DR4,Dw14, and DR4,Dw15 beta-1 genes lends support to the hypothesis that, in some cases, human leukocyte antigen and disease association may involve the association of discrete disease-related epitopes rather than entire human leukocyte antigen genes and that these epitopes are immunologically relevant in terms of T cell recognition. The association of these polymorphisms with susceptibility to rheumatoid arthritis would then support the hypothesis that binding and presentation of "arthritogenic peptides" by major histocompatibility complex class II molecules is one of the pathogenic events in developing rheumatoid arthritis.

The molecular basis of susceptibility to rheumatoid arthritis: the conformational equivalence hypothesis

This is an interpretive review of recent immunologic and molecular biologic data concerning the molecular basis of susceptibility to rheumatoid arthritis. The central point of view was taken that the major histocompatibility complex (MHC) class II molecules encoding disease susceptibility function in an immune recognition event involving an antigen "X" that currently eludes characterization. The problem of understanding the meaning of the association of susceptibility with diverse MHC alleles such as DR4 (Dw4 and Dw14), DR1, and DRw10 is approached by detailed biochemical analysis that led to the identification of common stretches of amino acid sequence, presumably encoding conformationally equivalent structures. Non-classic MHC polymorphisms related to disease susceptibility but not associated with particular alleles such as identified by Ab 109d6 proved especially valuable in suggesting new directions for attempting to understand the significance of these associations. Consideration is given to the possibility that a family of either slightly different or identical conformations encoded in either cis or trans cumulatively confer the liability to develop rheumatoid arthritis, and implying a highly non-classic mode of inheritance. The available data do not permit a distinction between the possibilities that an antigen "X" was being presented to T cells or whether the distinctive conformations of the MHC class II molecule serve the same role as antigen "X" but are directly recognized by T cells. However, with additional data, some limited insight should be able to be inferred about the nature of an antigen "X" that specifically binds to the MHC conformation with a complementary interaction. It seems reasonable to consider the pathogenesis of rheumatoid arthritis as a typical immune response resulting from a simple immune recognition event of a single antigenic molecule.

Associations of HLA-DR4 with rheumatoid factor and radiographic severity in rheumatoid arthritis

Possible associations between HLA-DR4 and laboratory, radiographic, joint count, functional, and demographic measures of clinical status were analyzed in 154 white patients with rheumatoid arthritis. Overall, 65 percent of the patients were HLA-DR4 positive, similar to other series. HLA-DR4 was associated significantly with the presence of rheumatoid factor and more severe radiographic changes. HLA-DR4 was not associated with significant differences in demographic, joint count, or functional measures of clinical status. HLA-DR1 was not associated significantly with differences in the presence of rheumatoid factor, radiographic changes, or other measures of clinical status. Selective associations of HLA-DR4 with rheumatoid factor and radiographic scores were more marked in men than in women. Patients who were putatively homozygous for HLA-DR4 were all seropositive and had more severe radiographic changes than patients who were heterozygous for HLA-DR4.

Gold induced thrombocytopenia: 12 cases and a review of the literature

Gold induced thrombocytopenia is immune mediated, with the production of platelet associated IgG leading to peripheral platelet destruction. An association with HLA-DR3 has been demonstrated. Corticosteroid therapy is effective in treatment, although other modes of therapy may be as efficacious.

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.

Immunogenetics of rheumatoid arthritis in Israel

In an attempt to study the variation of associations between HLA and rheumatoid disease a population of 44 Ashkenazi and 29 non-Ashkenazi patients with Rheumatoid Arthritis were tested for HLA-A, B, C and DR antigens and compared with the relevant control groups. In contrast to the results obtained in Middle European or North American Caucasians, Rheumatoid Arthritis in Israel is not associated with B15 and Cw3, indicating that it is very unlikely that B- and C-locus antigens are involved in coding for disease susceptibility for RA. The allele DR4 which is found associated with RA in almost all populations tested so far was in the total patient group (47.9%) slightly but not significantly more frequent than in the control group (38.3%). This difference was entirely due to a nonsignificant increase in the frequency of DR4 in the Ashkenazi patients (54.5%) compared to controls (40%), while the frequency of DR4 in non-Ashkenazi patients and controls was virtually identical (38.0% vs 36.7%). Another surprising finding was that the frequency of HLA-DR1, which has been reported to be increased in different populations of patients with RA was found to be completely normal in the present study on Israeli patients. The alleles of the Bf and the GLO system did not show any significant difference between patients and controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Shared T cell recognition sites on human histocompatibility leukocyte antigen class II molecules of patients with seropositive rheumatoid arthritis

Seropositive rheumatoid arthritis (RA) in adult and juvenile patients is associated with the serologic marker HLA-DR4. This association is incomplete; about one-third of the patients lack the disease-associated HLA-DR4 haplotype. The main biological function of class II molecules is to restrict the recognition of antigen by T lymphocytes. We therefore tested the hypothesis that patients with seropositive RA share T cell recognition sites for an unknown antigen and that such T cell "epitopes" are not identified by conventional serologic typing. We generated alloreactive human T cell clones by stimulating peripheral blood lymphocytes of normal donors against a lymphoblastoid cell line from a juvenile patient with seropositive RA. A panel of clones that recognized only HLA-Dw14 cells on a panel of homozygous typing cells was used to analyze class II molecules of adult patients with seropositive RA. By inhibition studies using monoclonal antibodies, the epitopes recognized by the different clones could be further characterized and assigned either to DR- or to DQ-encoded cell surface products. By using four different clones, it was possible to identify Dw14-associated T cell epitopes on all seropositive rheumatoid patients tested who typed HLA-DR4-positive and also on all eight DR4-negative patients tested. Approximately one-half of nonrheumatoid DR4-positive donors carried one or more determinants recognized by these clones; the expression of these allodeterminants in DR4-negative nonrheumatoid patients was rare (less than 10%). Thus, alloreactive human T cell clones are powerful tools to define T cell recognition sites on class II molecules that are not identified by conventional typing. Using T cell clones with specificities for determinants expressed on Dw14 homozygous typing lines, we were able to demonstrate shared epitopes on cells of all patients tested with seropositive RA irrespective of their HLA-D or HLA-DR type. These data suggest that major histocompatibility complex class II antigens of RA patients might be much more homogeneous than demonstrated by the incomplete HLA-DR4 association.

Antibodies to collagen types I-VI in Dupuytren's contracture

Sera from 16 patients with Dupuytren's contracture were tested for IgG and IgM antibodies to native and denatured human collagen types I, II, III, IV, V and VI. IgG antibody to at least one collagen type was found in 11/16 (69%) of these patients, compared with 27/96 (28%) normal adult blood donor controls. The prevalence of antibody to denatured type II collagen was raised, and although there was no overall increase in HLA-DR4 compared with a control population, this antibody was associated with HLA-DR4 in this patient group.

HLA-D antigens in rheumatoid arthritis and toxicity to gold and penicillamine

The frequencies of HLA-D antigens were investigated in 77 Finnish patients who met the ARA criteria of classical or definite rheumatoid arthritis. The control material consisted of healthy blood donors. HLA-Dw4 was significantly (p less than 0.01) increased and HLA-Dw2 significantly (p less than 0.01) decreased in the patients. All HLA-Dw4-positive patients belonged to the seropositive group and in comparison with controls HLA-Dw4 antigen was increased highly significantly (p less than 0.001) in the seropositive patients. With respect to HLA-Dw4 antigen, the seropositive and the seronegative group differed significantly (p less than 0.05). All patients had received penicillamine treatment and 75 of them gold treatment before penicillamine. No significant associations were noted between any HLA-D antigen and gold or penicillamine toxicity. The previous gold toxicity seemed to be a significant factor with respect to the subsequent penicillamine toxicity.

HLA antigens and toxic reactions to sodium aurothiopropanol sulphonate and D-penicillamine in patients with rheumatoid arthritis

One hundred and forty-one patients with rheumatoid arthritis treated with aurothiopropanol sulphonate or D-penicillamine, or both were examined for HLA antigens to investigate the genetic influence on the occurrence of different adverse reactions during therapy. All 13 patients possessing HLA-DR3 had toxic reactions. The relative risk for DR3 positives of developing skin eruptions or proteinuria was calculated to be 10.5 times and seven times respectively that of DR3 negatives. The incidence of DR7 antigen in 94 patients with toxic reactions was significantly decreased (11% compared with 28% in controls) suggesting a protective role for this antigen.

HLA genotypes in two three-generation families with rheumatoid arthritis

Two three-generation families from Northern Sweden with rheumatoid arthritis (RA) were clinically examined. Tissue typing was performed for HLA-A, -B, -C, and -DR antigens. No disease-associated haplotype could be defined within these families. Six of nine members with RA were HLA-DR4 positive. Both families had a HLA-DR4 containing haplotype in the first generation and second-generation members married DR4 positive individuals, which probably increased the risk to develop RA in the third-generation members.

HLA antigens and adverse drug reactions to sodium aurothiomalate and D-penicillamine in patients with rheumatoid arthritis

The association between HLA antigens and adverse drug reactions (ADR), (e.g. proteinuria, haematological abnormalities, stomatitis, diarrhoea and dermatitis) in rheumatoid arthritis (RA) to sodium aurothiomalate (gold) and to D-penicillamine (PA) were studied in 32 patients. Thirty-eight RA patients treated with gold and PA, and with no ADR to these drugs, were used as controls. The frequency of HLA B8 was significantly (p less than 0.05) increased among RA patients with ADR compared to plasma donors. DR3 was also significantly increased (p less than 0.05) in RA patients with haematological ADR compared to plasma donors. Haematological ADR occurred significantly (p less than 0.05) more often in DR3 positive patients (55%) than among DR3 negative RA patients (27%).

HLA polymorphisms in Nigerians

The HLA class I and class II phenotypes of a panel of 114 unrelated Nigerians have been determined. The panel was tested for all the known class I antigens and comparisons of the HLA-A and -B frequencies with those of other African Negroid populations revealed some differences. Only limited comparisons could be made for the HLA-DR and -D frequencies as these are not available for any well-defined African Negroid population. The data concerning the class II antigens of this panel are the most interesting. Half of the DRw11-positive panel members are DQw3 negative and DQw1 positive. In addition, there is dissociation of some HLA-D and -DR specificities, a number of panel members are positive for an HLA-D specificity and are negative for the corresponding HLA-DR specificity. Our results show the value of population studies in the investigation of the relationship between the different HLA class II antigens.

HLA antigens and seronegative rheumatoid arthritis

HLA antigens and clinical features in a series of 46 Caucasian patients (40 females, 6 males) and definite repeatedly seronegative rheumatoid arthritis (RA) of more than two years' duration (mean 11.6 years) were compared with those in 77 seropositive RA patients and 110 controls of the same ethnic and geographic origin. Seronegative RA appeared to be less often erosive than seropositive RA, and seronegative patients had fewer extra-articular features. The frequency of the HLA antigen DR1 was raised in seronegative patients as compared with controls (p = 0.006, relative risk = 3) and with seropositive patients (p less than 0.05). HLA-DR4 was slightly increased in seronegative patients compared with controls (p less than 0.05) but was clearly less so than in seropositive patients (p less than 0.005). Early onset of disease was very significantly associated with HLA-DR1 in seronegative patients (p = 0.007), whereas HLA-DR4 was present more frequently in seropositive patients with onset prior to age 35 (p less than 0.05). No correlation between HLA antigens and intolerance to drugs was found in seronegative patients, whereas in seropositive patients side effects to gold salts were associated with DR3. These results suggest that seropositive and seronegative RA have distinct HLA-DR associations, especially in disease of early onset, in addition to well established clinical differences.

Lack of HLA-antigen association in Greek rheumatoid arthritis patients

One hundred and eighteen unrelated Greek patients with classic rheumatoid arthritis (RA) were tissue-typed for HLA-A, -B, -DR antigens and the frequency was compared to that of healthy controls. Greek RA patients regardless of sex, anatomical severity, seropositivity and age at disease onset are not associated with any of the HLA alloantigens tested. Only an increased prevalence, not statistically significant, was observed of the HLA-DR5 antigen in the Ro (SSA) positive RA group.