By contrast to other proinflammatory cytokines which are found up-regulated in the skin of patients with psoriasis, atopic dermatitis or systemic sclerosis, IL-34 is the only cytokine that undergoes down-regulation. This finding is interesting regarding the description of IL-34 as an immunosuppressive cytokine. In this study, the expression and the role of interleukin-34 (IL-34) will be investigated in the physiopathology of systemic sclerosis.
The mechanisms involved in the physiopathology of systemic sclerosis (SSc) are not fully understood, particularly the pattern of cytokine expression in the skin of SSc patients. These cytokines are known to play a central role in the regulation of numerous inflammatory diseases and, among them, IL-34 is the only cytokine which has been found to be down-regulated in other skin inflammatory disorders such psoriasis or atopic dermatitis. IL-34 has been described as an immunosuppressive cytokine, and our preliminary results show that IL-34 is active on fibroblasts, a key cell that undergoes dysfunction in SSc. Thus, we are willing to explore its expression profile in the skin of SSc patients and its potential role in the physiopathology of the disease. For this study, we will analyze IL-34 mRNA levels in the skin and the plasma of SSc patients by comparison to healthy patients. Thirty patients will be included in the Internal Medicine Unit of the CHU de Poitiers during a single visit, in the frame of their medical follow-up, to collect two skin biopsies and 5 ml of blood after obtaining their informed consent. The expression of IL-34 will also be investigated at the protein level by immunostaining on skin sections and by ELISA (skin protein lysates and plasma). Moreover, the expression of other proinflammatory cytokines will be investigated both at the mRNA and protein levels.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
BASIC_SCIENCE
Masking
NONE
Enrollment
22
Two skin biopsies (4mm punch) are performed under local anesthesia at the site of cutaneous inflammation/fibrosis.
CHU de Poitiers
Poitiers, France
Skin IL-34 mRNA expression levels
Skin IL-34 mRNA expression levels (expressed in % of relative expression of GAPDH) in systemic sclerosis patients by comparison with healthy subjects. Skin biopsies are collected at D0 for SSc patients (inclusion day)
Time frame: 1 day
Immunostainings against IL-34 and other cytokines on skin sections
Immunostainings against IL-34 and other cytokines on skin sections from systemic sclerosis patients versus healthy skins
Time frame: 1 day
Protein expression levels of IL-34 and other cytokines by ELISA
Protein expression levels of IL-34 and other cytokines by ELISA (quantitative study) in plasma and lysates of skin biopsies from systemic sclerosis patients versus
Time frame: 1 day
Skin IL-34 mRNA expression levels of other cytokines
Skin IL-34 mRNA expression levels of other cytokines in patients with systemic sclerosis compared to healthy patients.
Time frame: 1 day
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