CD4 and tropical spastic paraparesis: To evaluate the relative expression of single and multiple co-expressed NCRs on CD4 and CD8 T cells during HTLV-1 infection, cryopreserved PBMCs from HTLV-1-infected asymptomatic carriers (AC, n = 20), HTLV-1-infected individuals diagnosed with HAM/TSP (HAM/TSP, n = 6) and seronegative controls (SC, n = 12) were assessed for expression of PD-1, TIGIT, TIM-3, and LAG-3 (Table 1, Figure 1; Supplementary Figure 1).