Session Type: Abstract Submissions (ACR)
We recently reported elevated numbers of synovial fluid IL-17+CD4- T cells (mainly CD8+ (Tc17) cells) in Psoriatic Arthritis (PsA), correlating with clinical, serological and imaging measures of disease activity (1). These relationships are not found with CD4+ IL-17+ (Th17) synovial cells. Here we report the relationship of synovial fluid T cell cytokine expression with PsA clinical patterns, and the relationships between synovial fluid cytokine-expressing T cells.
Mononuclear cells from synovial fluid (SF) and peripheral blood (PB) samples from 22 patients with PsA were isolated and stimulated for three hours in vitro with PMA and ionomycin in the presence of GolgiStop. CD3+ T cells were investigated for cytokine expression (IL-17A, IFN-γ, TNF-α, IL-22, IL-21, IL-10) by flow cytometry. Clinical measures and Power Doppler Ultrasound (PDUS) of the affected joint were made at the time of joint aspiration.
Of 22 subjects, 16 (73%) had an oligoarthritis (<5 involved joints) and 6 (27%) a polyarticular pattern of PsA, with 9 (41%) having co-existing axial disease. 2 subjects had a history of dactylitis, 8 of enthesitis and 5 of nail disease.
All clinical subgroup patients had elevated synovial IL-17+CD4- and IL-17+CD4+ T cells compared to PB, which was significant in the oligo (p=0.001 and p=0.02 respectively) and axial groups (p=0.01 for both), with the polyarthritis group increase not statistically significant (p=0.06 for both), most likely due to low numbers.
TNF-α+CD4- T-cell frequency positively correlated with DAS28 (r=0.51, p=0.02) with a trend for TNF-α+CD4+ T-cells and DAS28 (r=0.43, p=0.07). In contrast to IL-17+CD4- T cells, there was no correlation between TNF-α+ T-cells and ESR, CRP or PDUS. IL-22+CD4- cells correlated with PDUS. No other T cell cytokine expression pattern correlated with clinical measures.
Relationships of cytokine expressing T cells were assessed for the percentages of IL-17+CD4- T cells and IFN-γ+, TNF-α+, IL-22+, IL-21+ and IL-10+ CD4- T-cells in PsA SF. Only TNF-α+ cells positively correlated with IL-17+ cells in the CD4- T-cell compartment (r=0.55, p=0.01). This relationship may be partly explained by the finding that 60% of IL-17+CD4- cells co-express TNF-α. IL-22 was co-expressed in 22% of IL-17+ CD4- T cells.
These data suggest that IL-17 expressing CD4- (CD8+) T cells are found in all articular patterns of PsA. The correlation of IL-17+ and TNF-α+ CD4- cells suggests that IL-17 and TNF-α may be related in expression as well as synergy of function.
Ref 1. Menon B,et al.Arthritis Rheumatol. 2014;66:1272-81.
L. S. Taams,
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ACR Meeting Abstracts - https://acrabstracts.org/abstract/immunological-and-clinical-relationships-of-synovial-il-17-t-cells-in-psoriatic-arthritis/