CD8A and Friedreich ataxia: The number of CD8+CD3−CD69− ISP cells in the thymus was 0.86×106, 0.42×106, 0.09×106 in AL, DR and FA groups, respectively, while that of mature CD8 single positive (SP) was 1×106 in the AL group, 0.5×106 in both DR and FA groups (Fig. 4B, 4C).