CD8A and plasma cell myeloma: To get insights into the potential in vivo relevance of the above findings, we evaluated the frequency of myeloma-reactive, NY-ESO-1-specific CD8+ T cells in a subgroup of 16 HLA-A2+NY-ESO-1+ MM patients, 10 of whom could be classified as KYNhi based on serum KYN (Figure 1A).