Inverse correlation between the frequency of iNKT cells and the proviral load in peripheral blood from HTLV-1–infected persons. The correlation between the HTLV-1 proviral load in PBMCs and the frequency of iNKT cells (A), CD56⁺CD16⁺ NK cells (B), mDCs (C), and pDCs (D) from HTLV-1–infected persons (ACs, n = 12; HAM/TSP patients, n = 13) was statistically analyzed using the Spearman rank correlation test.