The recent finding of impaired TRPM3 ion channel and Ca2+ mobilisation in NK cells (Marshall-Gradisnik et al. 2016; Nguyen et al. 2017, 2016; Cabanas et al. 2018, 2019a), provides further evidence of immune dysfunction in ME/CFS (Bansal et al. 2012; Eaton-Fitch et al. 2019; Lorusso et al. 2009). Here, TRPM3 is linked to immune system disorder.