Thus, the expression atlas of SIGIRR in healthy human PBMCs prompted us to focus on the function of SIGIRR in memory CD4 T cells, which are critical for host defense but are also major drivers of immune-mediated diseases (O'Shea and Paul 2010; Borst et al. 2018; Beek et al. 2021), such as RA (Jiang et al. 2020; Raphael et al. 2020). The gene discussed is CD4; the disease is rheumatoid arthritis.