AUTHOR=Theodoropoulou Katerina , Wittkowski Helmut , Busso Nathalie , Von Scheven-Gête Annette , Moix Isabelle , Vanoni Federica , Hengten Veronique , Horneff Gerd , Haas Johannes-Peter , Fischer Nadine , Palm-Beden Katharina , Berendes Rainer , Heubner Georg , Jansson Annette , Lainka Elke , Leimgruber Annette , Morris Michael , Foell Dirk , Hofer Michaël 

TITLE=Increased Prevalence of NLRP3 Q703K Variant Among Patients With Autoinflammatory Diseases: An International Multicentric Study

JOURNAL=Frontiers in Immunology

VOLUME=11

YEAR=2020

URL=https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2020.00877

DOI=10.3389/fimmu.2020.00877

ISSN=1664-3224

ABSTRACT=<p><bold>Background:</bold> The <italic>NLRP3</italic> inflammasome has been recognized as one of the key components of innate immunity. Gain-of-function mutations in the exon 3 of <italic>NLRP3</italic> gene have been implicated in inflammatory diseases suggesting the presence of functionally important sites in this region. Q703K (c.2107C&gt;A, p.Gln703Lys, also known in the literature as Q705K) is a common variant of <italic>NLRP3</italic>, that has been considered to be both clinically unremarkable or disease-causing with a reduced penetrance.</p><p><bold>Objectives:</bold> We aimed to investigate the potential genetic impact of the <italic>NLRP3</italic> variant Q703K in patients with recurrent fever presenting with two autoinflammatory diseases: PFAPA (periodic fever, aphthous stomatitis, pharyngitis and cervical adenitis) and CAPS (cryopyrin-associated periodic syndrome), as well as with undefined autoinflammatory disease (uAID).</p><p><bold>Methods:</bold> This is an international multicentric observational retrospective study characterizing the clinical phenotype of patients presenting with recurrent fever suspected to be of auto-inflammatory origin and where the Q703K <italic>NLRP3</italic> variant was found. Monocytes of parents of 6 Q703K+ PFAPA patients were studied and levels of pro-inflammatory cytokines produced by monocytes of Q703K+ and Q703K- parents have been compared by ELISA.</p><p><bold>Results:</bold> We report 42 patients with the Q703K <italic>NLRP3</italic> genetic variant: 21 were PFAPA patients, 6 had a CAPS phenotype, and 15 had an uAID. The phenotypes of PFAPA, CAPS and uAID were quite similar between Q703K positive and negative patients with the exception of increased prevalence of pharyngitis in the Q703K positive CAPS population compared to the negative one. The <italic>in vitro</italic> production of IL-1β was not significantly different between Q703K+ and Q703K- monocytes from asymptomatic parents.</p><p><bold>Conclusion:</bold> The evidence we report in our study shows an increased prevalence of <italic>NLRP3</italic> Q703K in patients with autoinflammatory diseases, suggesting an association between the Q703K variant and the risk of PFAPA, CAPS and uAID syndromes. However, we did not show a functional effect of this mutation on the inflammasome basal activity.</p>