CD8A and systemic sclerosis: Increased CD8+ T cell clonality observed in the lungs and blood of SSc patients suggests proliferation in response to an immunogenic antigen (Yurovsky et al., 1996; Servaas et al., 2021), and activated CD8+ T cells have been identified in the skin, and isolated from the fibrotic lungs of SSc patients, where they express pro-fibrotic cytokines which stimulate fibroblast proliferation and collagen production (Atamas et al., 1999; Li et al., 2017).