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

Genetic risk score predicting risk of rheumatoid arthritis phenotypes and age of symptom onset

Background

Cumulative genetic profiles can help identify individuals at high-risk for developing RA. We examined the impact of 39 validated genetic risk alleles on the risk of RA phenotypes characterized by serologic and erosive status.

Methods/Principal Findings

We evaluated single nucleotide polymorphisms at 31 validated RA risk loci and 8 Human Leukocyte Antigen alleles among 542 Caucasian RA cases and 551 Caucasian controls from Nurses' Health Study and Nurses' Health Study II. We created a weighted genetic risk score (GRS) and evaluated it as 7 ordinal groups using logistic regression (adjusting for age and smoking) to assess the relationship between GRS group and odds of developing seronegative (RF− and CCP−), seropositive (RF+ or CCP+), erosive, and seropositive, erosive RA phenotypes. In separate case only analyses, we assessed the relationships between GRS and age of symptom onset.

In 542 RA cases, 317 (58%) were seropositive, 163 (30%) had erosions and 105 (19%) were seropositive with erosions. Comparing the highest GRS risk group to the median group, we found an OR of 1.2 (95% CI = 0.8–2.1) for seronegative RA, 3.0 (95% CI = 1.9–4.7) for seropositive RA, 3.2 (95% CI = 1.8–5.6) for erosive RA, and 7.6 (95% CI = 3.6–16.3) for seropositive, erosive RA. No significant relationship was seen between GRS and age of onset.

Conclusions/Significance

Results suggest that seronegative and seropositive/erosive RA have different genetic architecture and support the importance of considering RA phenotypes in RA genetic studies.

Management Issues with Elderly-Onset Rheumatoid Arthritis

Elderly-onset rheumatoid arthritis (EORA) is defined as rheumatoid arthritis (RA) starting at >60 years of age. EORA is characterised by a lower female/male ratio compared with RA in younger patients and it more frequently has an acute onset accompanied by constitutional symptoms. Two incompletely overlapping subsets of RA have been recognised: one exhibits the classical RA clinical picture while the other has a polymyalgia rheumatica-like appearance, characterised by shoulder involvement, absence of rheumatoid factor and, usually, by a nonerosive course. Identification of anti-cyclic citrullinated peptide antibodies is useful for distinguishing the latter subset from true polymyalgia rheumatica. Elderly-onset spondyloarthritis, crystal-related arthritis, remitting seronegative symmetrical synovitis with pitting oedema syndrome and hepatitis C virus-related arthritis must also be considered in the differential diagnosis. EORA treatment requires prudence because of the increase in age-related risks pertaining principally to the renal, cardiovascular and gastrointestinal systems. No groups of molecules usually employed for RA therapy in younger subjects (analgesics, NSAIDs, corticosteroids, disease-modifying antirheumatic drugs, anticytokine drugs) can be excluded a priori from the treatment of EORA patients. Nevertheless, the risk/benefit ratio relating to their use must be accurately evaluated for every single patient. Recently marketed compounds such as leflunomide and tumour necrosis factor-alpha antagonists have also increased the therapeutic opportunities for aged RA patients.

Systemic autoimmune diseases in elderly patients:

The possible consequences of the progressive 'ageing' of the immune system are the increase in autoimmune phenomenon, incidence of neoplasia and predisposition to infections. This review analyses the clinical expression of the systemic autoimmune diseases in older patients, focusing on three specific characteristics: the frequent atypical presentation of autoimmune diseases in the elderly, the higher morbidity and mortality of these patients and the frequent association with neoplasic processes. The study of autoimmune manifestations in elderly populations should be considered a priority for future medical research because of increasing life expectation, especially in developed countries.

Autoimmunity and geriatrics: clinical significance of autoimmune manifestations in the elderly

The immune system undergoes continuous morphologic and functional changes throughout the years, and it is now believed that the immune response has its peak function in puberty and gradually decreases with age (immunosenescence). Recent studies in healthy octogenarian patients suggest that the immune system, instead of suffering a generalized deterioration, undergoes a remodelling/readjustment of its major functions. Increase in two contrasting phenomena coexist in immunosenescence: on the one hand, a decrease in the capacity of the immune response and, on the other hand autoantibody production. The possible consequences of this progressive 'ageing' of the immune system are the increase in autoimmune phenomena, incidence of neoplasia and predisposition to infections. The study of autoimmune manifestations in elderly populations should be considered a priority for future medical research because of increasing life expectancy, especially in developed countries. This review analyses the main immune disorders associated with immunosenescence, the prevalence and clinical significance of autoantibodies in the elderly and the clinical expression of the main autoimmune diseases in older patients.

Elderly-onset rheumatoid arthritis

It is appreciated that age has a modifying effect on the clinical presentations of disorders such as hyperthyroidism and systemic lupus erythematosus. Similarly in EORA, there seems to be a change in the disease phenotype when it is compared to YORA. These differences are significant not only in highlighting the importance of the aging process on the immune system but also because they have medical and therapeutic implications. Improved classification has greatly improved our understanding and treatment of systemic lupus erythematosus, juvenile chronic arthritis, and seronegative spondyloarthropathies. Similarly, appreciating the differences, and similarities, between YORA and EORA should advance the choice of therapeutic options and potentially move closer to defining pathogenesis and origin.

Quantifying the exact role of HLA-DRB1 alleles in susceptibility to inflammatory polyarthritis: results from a large, population-based study

OBJECTIVE

To accurately determine the contributions of HLA-DRB1 alleles in explaining susceptibility to inflammatory polyarthritis in a large, true population-based cohort of new-onset cases.

METHODS

A cohort of 680 consecutive patients with inflammatory polyarthritis, of whom 404 satisfied the American College of Rheumatology (ACR) criteria for rheumatoid arthritis (RA), was recruited from the population-based Norfolk Arthritis Register. All cases were compared with 286 local population controls. A standardized clinical assessment was performed on all patients. HLA-DRB1 phenotypes, including DR4 subtypes, were determined using a semiautomated, reverse dot-blot method. Results were expressed as odds ratios (OR) and 95% confidence intervals (95% CI).

RESULTS

There was only a modest association (OR 1.8, 95% CI 1.4-2.4) between inflammatory polyarthritis and the presence of any shared epitope (SE) allele; the strongest individual risk was with DRB1*0404 (OR 3.5, 95% CI 1.8-6.8). Comparison of the genotypes demonstrated that the effect of being SE homozygous (OR 2.1, 95% CI 1.5-3.0) was only moderately greater than the effect of being SE heterozygous (OR 1.3, 95% CI 1.1-1.6). The exception to this was genotypic combinations that included HLA-DRB1*0404, which exhibited ORs ranging up to 18.0. There were no differences between either the phenotype or genotype data when the patients were stratified by RA status (defined by the ACR criteria). In contrast, the associations were substantially stronger in patients who were positive for rheumatoid factor.

CONCLUSION

Previous studies had not been able to clarify whether the influence of HLA-DRB1 on RA was related to disease susceptibility or to disease severity and progression. These data on a unique population-based incident cohort suggest only weak effects on susceptibility, with the exception of the clearly distinct influence of HLA-DRB1*0404.

Rheumatoid arthritis in the elderly. Prevalence and optimal management

Elderly-onset rheumatoid arthritis (EORA), defined as rheumatoid arthritis (RA) with onset at age 60 years or over, differs slightly from younger-onset RA by a more equal gender distribution, a higher frequency of acute systemic onset with involvement of the shoulder, a higher disease activity, and, in later stages, more radiographic damage and functional decline. Several subsets of EORA are recognised, such as rheumatoid factor-positive RA, polymyalgia rheumatica and 'remitting seronegative symmetrical synovitis with pitting oedema'. These conditions can be difficult to distinguish from crystal-induced arthritis, osteoarthritis and paraneoplastic arthritis. The efficacy and tolerability of second-line drugs is similar in both age groups, but in the elderly caution is needed with the use of nonsteroidal anti-inflammatory drugs and prednisone.

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.

Rheumatoid factor, HLA-DR4, and allelic variants of DRB1 in women with recent-onset rheumatoid arthritis

OBJECTIVE

To examine the relationship of rheumatoid factor (RF) to HLA-DR4 and alleles of DRB1 in women with recent-onset rheumatoid arthritis (RA).

METHODS

Incident cases of RA were identified as part of a prospective, population-based case-control study. HLA typing was completed for 246 cases meeting criteria for definite or classic RA.

RESULTS

One hundred thirty-six patients (55%) were positive for DR4, and 130 (53%) were RF positive. DR4 was found to be strongly associated with seropositivity (odds ratio 4.1, P < 0.0001). Patients with a shorter interval from RA onset to RF testing had a higher frequency of seropositivity than those with a longer interval (< or = 18 months 60%, > 18 months 33%). Further analysis of patients who had RF testing within 18 months of RA onset showed that the frequency of seropositivity was significantly greater among DR4-positive patients who had the shared sequence stretch of DR beta 1 associated with RA susceptibility (76% RF positive) than among DR1-positive patients who had this sequence (45% RF positive) (odds ratio 3.8, P = 0.01). Moreover, the frequency of seropositivity among DR1-positive patients with the sequence did not differ from that among all patients without the shared sequence (47%) (odds ratio 0.9, P = 0.8).

CONCLUSION

HLA-DR4 is strongly associated with seropositivity in women with recent-onset RA. The amino acid sequence of DR beta 1 that is associated with susceptibility to RA and is shared between DR4 and DR1 appears not to be the primary determinant of seropositivity in these women.

Vesiculobullous mucocutaneous disease: pemphigus vulgaris

Pemphigus vulgaris is a potentially fatal autoimmune mucocutaneous disease in which oral lesions may be the initial and predominant manifestation. The disease is characterized by acantholysis in the immediately suprabasal layers of the stratified squamous epithelium, giving rise to blisters which readily rupture leaving erosions which show little tendency to heal. Immunogenetic studies indicate a marked genetic susceptibility to the disease, with the immune response-associated HLA-DR4 and DRw6 alleles being especially important. The trigger for autoantibody formation is unknown. The antigen in pemphigus vulgaris is probably a 130-140 kD cell adhesion molecule located in the cell membrane of basal and immediately suprabasal keratinocytes. Antibody binding to this antigen is likely to interfere with normal intercellular adhesion, leading to desmosomal detachment. Propagation of acantholysis and cell damage are attributable to complement activation, with deposition of the membrane attack complex on the keratinocyte cell membrane, and proteolysis due to increased plasminogen activator production. Steroid therapy is the treatment of choice, but significant mortality is still associated with the disease.