RESEARCH - Systemic levels of IL-23 are strongly associated with disease activity in RA by not SpA

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Ann Rheum Dis. 2009 Feb 5.

Systemic levels of IL-23 are strongly associated with disease activity

in rheumatoid arthritis but not spondyloarthritis.

Melis L, Vandooren B, Kruithof E, Jacques P, De Vos M, Mielants H,

Verbruggen G, De Keyser F, Elewaut D.

Ghent University Hospital, Belgium.

OBJECTIVES: Th17 cells are an effector T-cell population that plays a

role in several chronic inflammatory conditions and are dependent on

IL-23 for their survival and expansion. More recently, a genetic

association was discovered between polymorphisms in the gene coding

for the IL-23R and spondyloarthritis (SpA). Our aim was to evaluate

the role of Th17 associated cytokines in SpA pathogenesis by measuring

their levels in the joints and circulation of SpA patients as well as

correlating them with disease activity parameters.

METHODS: Paired synovial fluid (SF), serum and synovial biopsies were

obtained from 30 non-PsA (non-psoriatic arthritis) SpA, 22 PsA and 22

rheumatoid arthritis (RA) patients. Interleukin-17, IL-23 and CCL20

were measured by ELISA in the SF and serum of the patients and

correlated with systemic and local parameters of disease activity.

RESULTS: SF IL-17 levels tended to be higher in non-PsA SpA compared

to PsA and RA patients, whereas SF IL-23 levels were similar.

Concentrations of CCL20, a major Th17 attracting chemokine, tended to

be higher in the joints of RA than in SpA patients. Interestingly,

levels of CCL20 were markedly higher in synovial fluid as opposed to

serum. In addition, there was a remarkable association between the

expression of the Th17 cytokine system and the presence of intimal

lining layer hyperplasia in RA. Also in the serum, there was a

tendency for higher IL-23 levels in RA, which correlated strongly with

disease activity parameters.

CONCLUSIONS: Th17 related cytokines are expressed in joints of SpA as

well as RA patients. IL-23 levels, however, correlate with disease

activity parameters in RA only. These results point towards a

differential regulation of the Th17 cytokine system in SpA compared to

RA.

PMID: 19196728

http://www.ncbi.nlm.nih.gov/pubmed/19196728

Not an MD