Both MDS patients had a PR-1- or WT-1-specific CD8+ T-cell response and experienced only grade 1 toxicities [24, 29] While repeated vaccination led to preferential proliferation of low-avidity CD8+ T-cell and loss of vaccine immunogenicity, anti-leukemic activity detected by reduction in WT-1 transcripts correlated positively with the presence of high-avidity CD8+ T cells in two patients and both patients had stable disease for > 2 years [24, 29]. Here, WT1 is linked to myelodysplastic syndrome.