HOPX and thrombotic thrombocytopenic purpura: Correlation of ribosomal gene expression with transcripts typically expressed in NK cells (KLRB1/CD161, CD244, GZMA, IFNG) [41,49–51] and certain subsets of T-lymphocytes (MAF, HOPX, GZMA, IFNG, CD52, KLRB1/CD161) [51–57] is consistent with activation and proliferation of one or more subsets of these cells in TTP patients with a history of relapse.