Skin-homing, cutaneous lymphocyte‒associated antigen (CLA)+, CCR4+ CD4+ (Clark et al., 2006a; Ferran et al., 2013) T cells proliferated in response to B. safensis (Figure 8a), which suggests homing of Bacillus antigen‒reactive T cells to CTCL lesions in this individual. The gene discussed is CCR4; the disease is primary cutaneous T-cell non-Hodgkin lymphoma.