Background Psoriatic arthritis is an inflammatory with an increase of cytokine production when compared to healthy subjects but with contradictory data due to its heterogeneity and according to its activity, its clinical presentation and/or the presence of comorbidity.

Objectives To study the sera and ex vivo cytokines secreted by mononuclear cells before and after stimulation of monocytes and lymphocytes through comparison of different groups of patients and according to activity, clinical presentation and comorbidity.

Methods Patients with psoriatic arthritis according to the Moll and Wright criteria have been clinically evaluated by a rheumatologist and a dermatologist. Active disease was defined by either more than 3 painful and swollen joints or a BASDAI higher than 40. Inflammatory syndrome was considered to be present when the CRP exceeded 10 mg/l. Cytokines dosage (IL-1a, IL1b, IL-1Ra, TNFa, IL-6, IL-17, IFNg, IL-4 and IL-10) in the serum and after mononuclear cell (MNC) extraction was carried out with luminex before and after stimulation with LPS on the one hand and by CD3-CD28 on the other hand.

Results Thirty-six patients with PsA were monitored. Mean age was 52 years and mean disease duration was 15.9 years. The sex ratio was 21 men (58.3%) and 15 women (41.7%). Thirty-four per cent had hypertension, 6% diabetes and 41% dyslipidemia; 51% were current smokers, 76% drank alcohol regularly and 27% were heavy drinkers. 72% had psoriasis on the day of the visit with a PASI (psoriasis area and severity index) averaging 5.1. Three of them had an axial form, 19 a peripheral form and 14 had both. In the serum, IFNg was increased; IL4 was decreased but not significantly while TNFa, was significantly increased in patients with psoriatic arthritis. When cytokines production of MNC in patients and healthy subjects was compared, we observed a significant increase of IL1ra (p=0,02), IL-10 (p=0,02), IL-6 (p<0,0005) and TNFa (p<0,001) in the absence of stimulation, an increase of IL-1a, IL1b, TNFa, IL-6 after stimulation with LPS and no significant difference after CD3-CD28 stimulation. When patients had active disease, there was no difference with regard to TNFa or IL6, whereas IL4 production was heightened after LPS stimulation. In the axial form, there was no TNFa increase compared to healthy subjects and in the peripheral form an IFNg increase and significantly heightened IL17 after CD3-CD28 stimulation were observed. No differences according to comorbidity were found.

Conclusions In psoriatic arthritis, the pro-inflammatory cytokines involved are IL-1, TNF alpha and l’IL-17, while for the anti-inflammatory, cytokines involved are l’IL1RA, l’IL10 et l’IL4 with differences depending largely on clinical presentation and disease activity.

Disclosure of Interest None Declared