Substantial reduced SLAMF4 + CD8 + T cells were detected in SLE patients, resulting in weakened cytotoxic capacity and an impaired ability to combat infection [43, 45]. The inhibition of CD160 to CD160-ligand coupling revived CD8 T-cell proliferation, and the degree of restoration was proportional to the ex vivo CD160 + CD8 T cells, demonstrating that CD160-associated CD8 T-cell dysfunction exists independently of PD-1 expression [46]. This evidence concerns the gene PDCD1 and systemic lupus erythematosus.