Rheumatoid Arthritis: Campbell C

Johnsen AK, Plenge RM, Butty V, Campbell C, Dieguez-Gonzalez R, Gomez-Reino JJ, Shadick N, Weinblatt M, Gonzalez A, Gregersen PK, Benoist C, Mathis D. · Joslin Diabetes Center, Harvard Medical School, Boston, Massachusetts, USA. · Arthritis Rheum. · Pubmed #18576312 links to  free full text

Abstract: OBJECTIVE: It has been suggested that polymorphisms in IL1 are correlated with severe and/or erosive rheumatoid arthritis (RA), but the implicated alleles have differed among studies. The aim of this study was to perform a broad and well-powered search for association between allelic polymorphism in IL1A and IL1B and the susceptibility to or severity of RA. METHODS: Key coding and regulatory regions in IL1A and IL1B were sequenced in 24 patients with RA, revealing 4 novel single-nucleotide polymorphisms (SNPs) in IL1B. These and a comprehensive set of 24 SNPs tagging most of the underlying genetic diversity were genotyped in 3 independent RA case-control sample sets and 1 longitudinal RA cohort, totaling 3,561 patients and 3,062 control subjects. RESULTS: No fully significant associations were observed. Analysis of the discovery case-control sample sets indicated a potential association of IL1B promoter region SNPs with susceptibility to RA (for RA3/A, odds ratio [OR] 1.27, P = 0.0021) or with the incidence of radiographic erosions (for RA4/C, OR 1.56, P = 0.036), but these findings were not replicated in independent case-control samples. No association with rheumatoid factor, anti-cyclic citrullinated peptide, or the Disease Activity Score in 28 joints was found. None of the associations previously observed in other studies were replicated here. CONCLUSION: In spite of a broad and highly powered study, we observed no robust, reproducible association between IL1A/B variants and the susceptibility to or severity of RA in white individuals of European descent. Our results provide evidence that, in the majority of cases, polymorphism in IL1A and IL1B is not a major contributor to genetic susceptibility to RA.

Leung BP, Sattar N, Crilly A, Prach M, McCarey DW, Payne H, Madhok R, Campbell C, Gracie JA, Liew FY, McInnes IB. · Department of Immunology, Glasgow Royal Infirmary, University of Glasgow, Glasgow, United Kingdom. · J Immunol. · Pubmed #12538717 links to  free full text

Abstract: 3-Hydroxy-3-methylglutaryl-CoA reductase inhibitors (statins) exert favorable effects on lipoprotein metabolism, but may also possess anti-inflammatory properties. Therefore, we explored the activities of simvastatin, a lipophilic statin, in a Th1-driven model of murine inflammatory arthritis. We report in this study that simvastatin markedly inhibited not only developing but also clinically evident collagen-induced arthritis in doses that were unable to significantly alter cholesterol concentrations in vivo. Ex vivo analysis demonstrated significant suppression of collagen-specific Th1 humoral and cellular immune responses. Moreover, simvastatin reduced anti-CD3/anti-CD28 proliferation and IFN-gamma release from mononuclear cells derived from peripheral blood and synovial fluid. Proinflammatory cytokine production in vitro by T cell contact-activated macrophages was suppressed by simvastatin, suggesting that such observations have direct clinical relevance. These data clearly illustrate the therapeutic potential of statin-sensitive pathways in inflammatory arthritis.

Leung BP, Culshaw S, Gracie JA, Hunter D, Canetti CA, Campbell C, Cunha F, Liew FY, McInnes IB. · Department of Immunology and Bacteriology, Western Infirmary, University of Glasgow, Glasgow, United Kingdom. · J Immunol. · Pubmed #11509635 links to  free full text

Abstract: IL-18 expression and functional activity has been identified in several autoimmune and infectious diseases. To clarify the potential role of IL-18 during early innate immune responses, we have explored the capacity of IL-18 to activate neutrophils. Human peripheral blood-derived neutrophils constitutively expressed IL-18R (alpha and beta) commensurate with the capacity to rapidly respond to IL-18. IL-18 induced cytokine and chemokine release from neutrophils that was protein synthesis dependent, up-regulated CD11b expression, induced granule release, and enhanced the respiratory burst following exposure to fMLP, but had no effect upon the rate of neutrophil apoptosis. The capacity to release cytokine and chemokine was significantly enhanced in neutrophils derived from rheumatoid arthritis synovial fluid, indicating differential responsiveness to IL-18 dependent upon prior neutrophil activation in vivo. Finally, IL-18 administration promoted neutrophil accumulation in vivo, whereas IL-18 neutralization suppressed the severity of footpad inflammation following carrageenan injection. The latter was accompanied by reduction in tissue myeloperoxidase expression and suppressed local TNF-alpha production. Together, these data define a novel role for IL-18 in activating neutrophils and thereby promoting early innate immune responses.