Vitamin D deficiency does not increase the risk of rheumatoid arthritis: Comment on the article by Merlino et al

“…In addition, an analysis of synovial tissue from a patient with rheumatoid arthritis has demonstrated that 51 (5.2%) of 990 identified synovial proteins exhibited citrullination, and 13 citrullinated autoantigens could unambiguously be assigned by mass spectrometry (54). Apart from fibrinogen, a major citrullinated autoantigen in these patients (55,56), all other proteins identified in this study (54) were polypeptides for which citrullination had not been described previously. Similarly, a comparative proteomic study (see Ref.…”

Section: Discussionsupporting

confidence: 55%

Citrullination-dependent Differential Presentation of a Self-peptide by HLA-B27 Subtypes

Beltrami

Rossmann

Fiorillo

et al. 2008

Journal of Biological Chemistry

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Inflammatory processes are accompanied by the posttranslational modification of certain arginine residues within proteins to yield citrulline, although it is largely unknown how this modification influences antigen presentation. We employed crystallographic and functional studies to investigate whether the exchange of arginine to citrulline affects the display of a peptide by two human major histocompatibility antigen class I subtypes, HLA-B*2705 and HLA-B*2709. Both differ only in residue 116 within the peptide binding groove despite their differential association with ankylosing spondylitis, an inflammatory rheumatic disorder. The crystal structures described here show that a modified self-peptide, pVIPR-U5 (RRKWURWHL; U ‫؍‬ citrulline), is presented by the two HLA-B27 molecules in distinct conformations. These binding modes differ not only drastically from each other but also from the conformations exhibited by the non-citrullinated peptide in a given subtype. The differential reactivity of HLA-B27-restricted cytotoxic T cells with modified or unmodified pVIPR supports the structural findings and shows that the presentation of citrullinated peptides has the potential to influence immune responses.

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“…Estimated baseline dietary vitamin D intake has been inversely associated with RA onset in an inception cohort study [14]. In contrast, a study of vitamin D levels measured in serum collected prior to diagnosis in 79 preclinical patients with RA compared with 139 controls found no diVerence in vitamin D levels at any time point 1 year, 2 years, or at 5 years prior to diagnosis [15].…”

Section: Discussionmentioning

confidence: 93%

The relationship between vitamin D and disease activity and functional health status in rheumatoid arthritis

et al. 2010

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We aimed to establish the relationship between serum vitamin D levels and disease activity and health status in rheumatoid arthritis. Sixty-five patients with RA fulfilling ACR criteria for the classification of rheumatoid arthritis and forty healthy controls were included in this study. Disease activity was assessed according to the Disease Activity Score including 28 joint counts. C-reactive protein (CRP, mg/dl) was determined by the nephelometric method. Erythrocyte sedimentation rate (ESR, mm/h) was determined by the Westergren method. Rheumatoid factor (RF, IU/ml) was also determined by the nephelometric method, and RF > 20 IU/ml was defined as positive. 25-OH Vitamin D EIA Kit was used to measure serum 25-OH Vitamin D levels. We found that the mean of the 25-OH D vitamin levels of the patients with RA was not different than that of controls (P = 0.936). We divided patients with RA into three groups according to DAS28 as low activity group (group 1, n = 25), moderate activity group (group 2, n = 25), and high activity group (group 3, n = 15). 25-OH vitamin D levels of the patients in the high activity group (group 3) were found to be the lowest (P < 0.001), and the patients with moderate disease activity had lower levels than those in the mild group (P = 0.033). Serum 25-OH vitamin D levels were significantly negatively correlated with DAS28, CRP, and HAQ (respectively, r = -0.431, P = 0.000, r = -0.276, P = 0.026, and r = -0.267, P = 0.031). Serum vitamin D levels in patients with RA were similar those in the healthy controls, while it significantly decreases in accordance with the disease activity and decreasing functional capacity.

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Vitamin D deficiency does not increase the risk of rheumatoid arthritis: Comment on the article by Merlino et al

Cited by 90 publications

References 9 publications

Is vitamin D in rheumatoid arthritis a magic bullet or a mirage? The need to improve the evidence base prior to calls for supplementation

Is vitamin D in rheumatoid arthritis a magic bullet or a mirage? The need to improve the evidence base prior to calls for supplementation

Citrullination-dependent Differential Presentation of a Self-peptide by HLA-B27 Subtypes

The relationship between vitamin D and disease activity and functional health status in rheumatoid arthritis

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