Association of HLA-DRB1 amino acid residues with giant cell arteritis: genetic association study, meta-analysis and geo-epidemiological investigation.

INTRODUCTION: Giant cell arteritis (GCA) is an autoimmune disease commonest in Northern Europe and Scandinavia. Previous studies report various associations with HLA-DRB1*04 and HLA-DRB1*01; HLA-DRB1 alleles show a gradient in population prevalence within Europe. Our aims were (1) to determine which amino acid residues within HLA-DRB1 best explained HLA-DRB1 allele susceptibility and protective effects in GCA, seen in UK data combined in meta-analysis with previously published data, and (2) to determine whether the incidence of GCA in different countries is associated with the population prevalence of the HLA-DRB1 alleles that we identified in our meta-analysis. METHODS: GCA patients from the UK GCA Consortium were genotyped by using single-strand oligonucleotide polymerization, allele-specific polymerase chain reaction, and direct sequencing. Meta-analysis was used to compare and combine our results with published data, and public databases were used to identify amino acid residues that may explain observed susceptibility/protective effects. Finally, we determined the relationship of HLA-DRB1*04 population carrier frequency and latitude to GCA incidence reported in different countries. RESULTS: In our UK data (225 cases and 1378 controls), HLA-DRB1*04 carriage was associated with GCA susceptibility (odds ratio (OR) = 2.69, P = 1.5×10(-11)), but HLA-DRB1*01 was protective (adjusted OR = 0.55, P = 0.0046). In meta-analysis combined with 14 published studies (an additional 691 cases and 4038 controls), protective effects were seen from HLA-DR2, which comprises HLA-DRB1*15 and HLA-DRB1*16 (OR = 0.65, P = 8.2×10(-6)) and possibly from HLA-DRB1*01 (OR = 0.73, P = 0.037). GCA incidence (n = 17 countries) was associated with population HLA-DRB1*04 allele frequency (P = 0.008; adjusted R(2) = 0.51 on univariable analysis, adjusted R(2) = 0.62 after also including latitude); latitude also made an independent contribution. CONCLUSIONS: We confirm that HLA-DRB1*04 is a GCA susceptibility allele. The susceptibility data are best explained by amino acid risk residues V, H, and H at positions 11, 13, and 33, contrary to previous suggestions of amino acids in the second hypervariable region. Worldwide, GCA incidence was independently associated both with population frequency of HLA-DRB1*04 and with latitude itself. We conclude that variation in population HLA-DRB1*04 frequency may partly explain variations in GCA incidence and that HLA-DRB1*04 may warrant investigation as a potential prognostic or predictive biomarker.

Mapping trabecular disconnection "hotspots" in aged human spine and hip.

Trabecular bone disconnection is an independent factor in age-related skeletal failure where real termini (ReTm; rare in youth) may cause weakness disproportionate to tissue loss, yet their structural contribution at vulnerable locations remains uncertain. ReTm (previously recorded at the iliac crest) were mapped in "normal" aged vertebral bodies (T11-L5 autopsy; 20 females, 10 males) and corresponding proximal femora (autopsy; 10 females). Results were compared with biomechanically failed femora from orthopaedic subjects aged >58 yr (osteoporosis OP, 10 females; osteoarthritis OA, 10 females). A novel direct 2D/3D histological method was applied to large, thick (300 µm) slices superficially silver-stained to separate ReTm (unstained) from apparent termini (planar artefacts, brown). Light microscope field co-ordinates enabled ReTm mapping and statistical testing relative to i) sex, ii) tissue sector and iii) slicing plane. In men ReTm populations were small and random while in women they were large and sector-specific. In vertebrae they clustered anterior/superior being rare posterior/inferior; in the femoral head they concentrated distal/superior and also near the fovea, being fewer distal/inferior. A distribution polarity was evident with 100% more ReTm observed transversely (i.e., on tensile-related cross struts) than longitudinally (i.e., on compression-related vertical struts). Their numbers rose in OP (BV/TV<14%, microCT) and in OA (BV/TV>14%), remaining polarised and sector-specific in OP only. Comparative experimentation by marrow elution of an OP animal model demonstrated "floating segments" as a possible outcome. Conclusions were supported statistically that trabecular disconnection "hotspots" at vulnerable locations are sex- and sector-specific, mainly transaxial, and subject to disease modulation.

Ischaemic manifestations in giant cell arteritis are associated with area level socio-economic deprivation, but not cardiovascular risk factors.

OBJECTIVES: To determine whether ischaemic manifestations of GCA are associated with pre-existing hypertension, atherosclerosis or area-level socio-economic deprivation. METHODS: We conducted an observational study of rheumatologist/ophthalmologist-diagnosed GCA in eight UK centres. The main outcome measure was ischaemic manifestations observed during active GCA: visual loss/blurring, aura, diplopia, jaw/tongue/limb claudication, cerebral/myocardial ischaemia or scalp necrosis. RESULTS: Out of 271 patients, 222 had ischaemic manifestations. Adjusted odds ratios (ORs) for the influence of hypertension and atherosclerosis were 1.6 (95% CI 0.8, 3.1) and 1.5 (0.6, 3.5). The most striking finding was an association of ischaemic manifestations with increasing Index of Deprivation 2007 score: OR 4.2 (95% CI 1.3, 13.6) for the most-deprived quartile compared with the least-deprived quartile. Similar effect sizes were seen within each recruitment centre. Deprivation was associated with smoking and negatively associated with previous polymyalgia. However, neither of these variables, nor hypertension or atherosclerosis, appeared responsible for mediating the effect of deprivation on ischaemic complications. Smoking was not associated with ischaemic manifestations. Median symptom duration before treatment was 30 days; after adjusting for symptom duration, the OR for ischaemic complications was 3.2 (95% CI 1.0, 10.8) for the most-deprived quartile compared with the least-deprived quartile. CONCLUSIONS: In GCA, area-level socio-economic deprivation was associated with ischaemic manifestations: this was not mediated by traditional cardiovascular risk factors. These findings are novel and require replication. Delay between first symptoms and treatment may play a role. Public awareness campaigns about GCA should aim especially to engage individuals living in more deprived areas to encourage early presentation and prompt treatment.

An unusual case of testicular pain.

We present the first case of lupus presenting with testicular pain in an Asian man. This gentleman presented with clear features of lupus with fever, joint pain, rash, diarrhoea and vomiting. He had typical serology consistent with active lupus. He also developed testicular pain and all his symptoms improved with oral steroids and azathioprine. It is therefore important to consider connective tissue disease in patients presenting with testicular pain that are systematically unwell.

Effect of the early use of the anti-tumor necrosis factor adalimumab on the prevention of job loss in patients with early rheumatoid arthritis.

OBJECTIVE: To compare work disability and job loss in early rheumatoid arthritis (RA) patients receiving adalimumab plus methotrexate (adalimumab + MTX) versus MTX alone. METHODS: In this multicenter, randomized, controlled trial, patients with RA for <2 years who had never taken MTX and who self-reported work impairment were randomized to adalimumab + MTX or placebo + MTX for 56 weeks. Primary outcome was job loss of any cause and/or imminent job loss at or after week 16. Secondary outcomes included disease activity, function (Health Assessment Questionnaire [HAQ] score), and RA quality of life (RAQoL) questionnaire score. Work was evaluated with work diaries and the RA Work Instability Scale. RESULTS: Although job loss during the 56-week study was significantly lower with adalimumab + MTX (14 of 75 patients) compared with MTX alone (29 of 73 patients; P=0.005), the primary end point was not met (12 of 75 versus 20 of 73 patients; P=0.092), likely owing to early drop out in the MTX group. There were significant improvements in American College of Rheumatology 20% response criteria, 28-joint Disease Activity Score, DeltaHAQ, DeltaRAQoL, and working time lost in the adalimumab + MTX group. Twenty-four serious adverse events were reported in 17 participants, with no differences between groups. CONCLUSION: Adalimumab + MTX reduced job loss and improved productivity in early RA when compared with MTX alone, which supports the early use of anti-tumor necrosis factor therapy and suggests its cost efficacy.