AUTHOR=Nesmond Stéphane , Muller Céline , Le Naour Richard , Viguier Manuelle , Bernard Philippe , Antonicelli Frank , Le Jan Sébastien 

TITLE=Characteristic Pattern of IL-17RA, IL-17RB, and IL-17RC in Monocytes/Macrophages and Mast Cells From Patients With Bullous Pemphigoid

JOURNAL=Frontiers in Immunology

VOLUME=10

YEAR=2019

URL=https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2019.02107

DOI=10.3389/fimmu.2019.02107

ISSN=1664-3224

ABSTRACT=<p>Inflammation is largely implicated in bullous pemphigoid (BP), the most frequent skin auto-immune blistering disease. IL-17, essentially IL-17A/F, has been involved in blister formation through regulation of protease production, and its specific serum profile within BP was related to disease outcome. However, relationships between IL-17 family ligands and receptors are quite complex with six different IL-17 isoforms, and five different receptors. We here aimed at clarifying the contribution of the IL-17 axis in BP by characterizing not only the expression of IL-17 receptor (IL-17R) members within immune cells isolated from BP patients (PMNs, <italic>n</italic> = 9; T-lymphocytes, <italic>n</italic> = 10; and monocytes, <italic>n</italic> = 10) but also the expression of IL-17 isoforms in sera (<italic>n</italic> = 83), and blister fluid (<italic>n</italic> = 31) of BP patients. We showed that at diagnosis, IL-17RA and IL-17RC expression were significantly increased in monocytes isolated from BP patients as compared to those from control subjects (<italic>p</italic> = 0.006 and <italic>p</italic> = 0.016, respectively). Notably, both IL-17RA and IL-17RC mRNA expression remained elevated in BP monocytes at time of relapse. We further demonstrated a significant increase of all IL-17 isoforms tested in BP blister fluid compared with BP serum (IL-17A, <italic>p</italic> &lt; 0.0001; IL-17A/F, <italic>p</italic> &lt; 0.0001; IL-17B, <italic>p</italic> = 0.0023; IL-17C, <italic>p</italic> = 0.0022; IL-17E, <italic>p</italic> &lt; 0.0001). Among all, IL-17B was the only cytokine for which a significant decreased concentration within blister fluid was observed in BP patients with severe disease compared to patients with moderate disease (<italic>p</italic> = 0.012). We further evidenced a significant negative correlation between IL-17B levels and blister/erosion BPDAI subscore (<italic>r</italic> = −0.52, <italic>p</italic> = 0.003). We finally identified mast cells as a potential target of IL-17B in lesional skin of BP patients. In conclusion, we showed here that IL-17RA and IL-17RC expression in monocyte was associated with disease activity and evidenced <italic>in situ</italic> a negative correlation between BP disease activity and IL-17B, whose effects could be mediated by IL-17RB expressed by mast cell in BP lesional skin.</p>