AUTHOR=Kessal Karima , Liang Hong , Rabut Ghislaine , Daull Philippe , Garrigue Jean-Sébastien , Docquier Mylene , Melik Parsadaniantz Stéphane , Baudouin Christophe , Brignole-Baudouin Françoise 

TITLE=Conjunctival Inflammatory Gene Expression Profiling in Dry Eye Disease: Correlations With HLA-DRA and HLA-DRB1

JOURNAL=Frontiers in Immunology

VOLUME=9

YEAR=2018

URL=https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2018.02271

DOI=10.3389/fimmu.2018.02271

ISSN=1664-3224

ABSTRACT=<p><bold>Purpose:</bold> In several multicenter clinical trials, HLA-DR was found to be a potential biomarker of dry eye disease (DED)'s severity and prognosis. Given the fact that HLA-DR receptor is a heterodimer consisting in an alpha and a beta chain, we intended to investigate the correlation of inflammatory targets with the corresponding transcripts, <italic>HLA-DRA</italic> and <italic>HLA-DRB1</italic>, to characterize specific targets closely related to HLA-DR expressed in conjunctival cells from patients suffering from DED of various etiologies.</p><p><bold>Methods:</bold> A prospective study was conducted in 88 patients with different forms of DED. Ocular symptom scores, ocular-staining grades, tear breakup time (TBUT) and Schirmer test were evaluated. Superficial conjunctival cells were collected by impression cytology and total RNAs were extracted for analyses using the new NanoString<sup>®</sup> nCounter technology based on an inflammatory human code set containing 249 inflammatory genes.</p><p><bold>Results:</bold> Two hundred transcripts were reliably detected in conjunctival specimens at various levels ranging from 1 to 222,546 RNA copies. Overall, from the 88 samples, 21 target genes showed a highly significant correlation (<italic>R</italic> &gt; 0.8) with <italic>HLA-DRA</italic> and <italic>HLA-DRB1, HLA-DRA</italic> and <italic>B1</italic> presenting the highest correlation (<italic>R</italic> = 0.9). These selected targets belonged to eight family groups, namely interferon and interferon-stimulated genes, tumor necrosis factor superfamily and related factors, Toll-like receptors and related factors, complement system factors, chemokines/cytokines, the RIPK enzyme family, and transduction signals such as the STAT and MAPK families.</p><p><bold>Conclusions:</bold> We have identified a profile of 21 transcripts correlated with <italic>HLA-DR</italic> expression, suggesting closely regulated signaling pathways and possible direct or indirect interactions between them. The NanoString<sup>®</sup> nCounter technology in conjunctival imprints could constitute a reliable tool in the future for wider screening of inflammatory biomarkers in DED, usable in very small samples. Broader combinations of biomarkers associated with HLA-DR could be analyzed to develop new diagnostic approaches, identify tighter pathophysiological gene signatures and personalize DED therapies more efficiently.</p>