CD4 and systemic lupus erythematosus: The presence of both CD4+ and CD8+ T cells in the affected tissues was confirmed in SLE patients (Li et al., 2007; Cohen et al., 2008; Crispin et al., 2008) and SSc patients (Almeida et al., 2015; Liu et al., 2016; Fuschiotti, 2018a,b).