Background Experimental studies indicate that interleukin-35 (IL-35) is an important anti-inflammatory cytokine and can efficiently suppress T effector cell activity and reduce the progression of inflammatory and autoimmune diseases. However, its real role in the pathophysiology of human diseases is still unclear.
Objectives To assess the serum IL-35 level and its association with clinical manifestations in patients with Systemic Sclerosis (SSc).
Methods IL-35 serum levels were measured by ELISA from 56 patients with SSc and 53 healthy controls. Association of IL-35 serum levels with clinical parameters were sought.
Results Serum IL-35 levels were significantly higher in SSc patients (5.08±0.76pg/ml) than in healthy individuals (1.89±0.69 pg/ml; P<0.0001). There were no differences in serum IL-35 levels between those with limited cutaneous SSc and those with diffuse cutaneous SSc (4.87±1.07 and 5.32±1.11 pg/ml, p=0.776), but both levels were higher than control group (p<0.0001). Patients with lung fibrosis had higher IL-35 levels than those without fibrosis (7.75±1.36 and 3.08±0.70 pg/ml, respectively, p=0.0022). Regarding treatment, patients taking azathioprine had increased IL-35 levels (8.81±1.81 pg/ml) compared to those not taking (4.35±0.82 pg/ml, p=0.0220).
Conclusions IL-35 is elevated in the serum of patients with SSc and is associated with lung fibrosis. Our findings suggest that this cytokine can have a role in fibrotic diseases but further studies are needed to address the role of IL-35 in the pathogenesis of SSc.
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Disclosure of Interest None declared