AB0058 Interferons and Systemic Sclerosis: Correlation Between Interferon Gamma and Interferon-Lambda 1 (IL-29)
Authors: A.T. Dantas, S.M.C. Gonçalves, M.C. Pereira, A.R. Almeida, C.D.L. Marques, M.J.B.D.M. Rego, I.D.R. Pitta, A.L.B.P. Duarte, M.G.D.R. Pitta
Journal: Annals of the Rheumatic Diseases (2015)

<h3>Background</h3> Interferon-lambda 1 (IFNl1), also known as Interleukin-29, belongs to the family of type III interferons and is produced by human peripheral blood mononuclear cells (PBMC) and dendritic cells. It was already described antiviral, anti-proliferative and antitumor effects of IFNl1, but immune-regulatory function is still gradually been elucidated. In human T cells, this cytokine was able to inhibit Th2 response by diminishing secretion of IL-4, IL-5 and, mainly, IL-13 but its real role in pathophysiology of human diseases is still unclear. <h3>Objectives</h3> To evaluate serum levels of IFNl1 in systemic sclerosis (SSc) patients and healthy controls and its association with Th1 and Th2 cytokines. <h3>Methods</h3> Serum samples were obtained from 52 SSc patients (49 women, 3 men) with a mean age of 44.8 years (range 19–79 yrs) and 53 sex and age matched healthy controls. ELISAs for serum levels of IFNl1, IFNg, TNFa, IL-13, IL-2, IL-4, IL-6 and IL-10 were performed with commercially available sandwich ELISA kits, according to the manufacturer9s instructions. <h3>Results</h3> IFNl1 levels in patients with SSc were significantly higher than those in healthy individuals (24.82±8.78 and 11.04±3.04 pg/ml, respectively; p&lt;0.0001). Also, SSc patients had higher IFNg levels than controls (34.11±8.11 and 10.73±2.77 pg/ml, respectively; p&lt;0.0001). Furthermore, we found a positive correlation between IL-29 and IFNg levels in SSc patients (p=0.0103, r=0.3526). IL-2, IL-4, IL-6, IL-10, IL-13 and TNFa were not detected in most of the patients and normal controls serum. We found that patients with myositis had higher IFNg levels than those without muscle involvement (p=0.0483) but no significant association was found between IL-29 levels and clinical manifestations. <h3>Conclusions</h3> IL-29 levels are increased in SSc and are positively correlated with IFNg levels, a Th1 cytokine. Because of its strong inhibitory effect on Th2 pathway demonstrated by previous studies, at this point, we can only speculate on the potential role of IL-29 as an anti-fibrotic cytokine and additional longitudinal studies are needed to evaluate this concern <h3>References</h3> Jordan WJ, Eskdale J, Srinivas S, Pekarek V, Kelner D, Rodia M, Gallagher G.Human interferon lambda-1 (IFN-lambda1/IL-29) modulates the Th1/Th2 response. Genes Immun. 2007 Apr;8(3):254-61. Srinivas S, Dai J, Eskdale J, Gallagher GE, Megjugorac NJ, Gallagher G. Interferon-lambda1 (interleukin-29) preferentially down-regulates interleukin-13 over other T helper type 2 cytokine responses in vitro. Immunology. 2008 Dec;125(4):492-502. Wu Q, Yang Q, Lourenco E, Sun H, Zhang Y. Interferon-lambda1 induces peripheral blood mononuclear cell-derived chemokines secretion in patients with systemic lupus erythematosus: its correlation with disease activity. Arthritis Res Ther. 2011 Jun 16;13(3):R88. <h3>Disclosure of Interest</h3> None declared