Fig. 2

HTLV-1 clone frequency distribution in sorted CD4⁺ and CD8⁺ cells. a Representative example of the difference in clonal distribution between CD4⁺ (left), CD8⁺ (middle) and unsorted (right) cells. Each slice of the pie chart represents a single observed clone, and the width of the slice is proportional to its relative abundance in the respective subject. The most abundant CD8⁺ clone constituted over 10 % of the load in CD8⁺ cells in this subject. OCI oligoclonality index [15]. b The HTLV-1 oligoclonality index was significantly higher in CD8⁺ cell samples than in CD4⁺ cell samples (p = 0.0005, paired Wilcoxon signed rank test). c The proportion of the load present in singletons (clones detected only once per sample) was significantly higher in CD4⁺ cells than in CD8⁺ cells (p = 0.002, Mann–Whitney test). d The oligoclonality index in CD8⁺ cells was significantly correlated with the proviral load in CD8⁺ cells (p = 0.017, Spearman’s rank correlation). No such correlation was observed in CD4⁺ cells or in unsorted PBMCs. e The observed total clone number (left panel) and estimated total number of clones in the blood (right panel) for sorted CD4⁺, CD8⁺ cells and unsorted PBMCs