Conclusion
The heterozygous stop-gain variant in IL37 (IL37 NM_014439.3:c.51G > A p.(Trp17*)) is not of functional relevance as we observed no clear pro-inflammatory phenotype in immune cells of a patient carrying this variant.
Methods
In this case study, the (hyper)responsiveness of immune cell subsets was investigated in a single patient with a seronegative autoimmune disorder who carries a heterozygous stop-gain variant in IL37 (IL37 Chr2(GRCh37):g.113670640G > A NM_014439.3:c.51G > A p.(Trp17*)). As the patient has been non-responsive to blockage of TNF or IL-1 by Etanercept or Anakinra, respectively, additional in-vitro experiments were set out to elucidate whether treatment with recombinant IL-37 could normalise observed immune cell functions. Findings: Characterisation of immune cell function showed no elevated overall production of acute-phase pro-inflammatory cytokines by patient PBMCs and neutrophils at baseline or upon stimulation. T-cell responses were elevated, as was the metabolic activity and IL-1Ra production of PBMCs at baseline. The identified stop-gain variant in IL37 does not result in the absence of the protein in circulation. In line with this, treatment with recombinant IL-37 did overall not dampen immune responses with the exception of the complete suppression of IL-17.