Clonal Expansions of Cytotoxic T Cells in the Blood of Patients with Waldenstrom's Macroglobulinaemia Are Anergic and Disappear After Nucleoside Analogue Therapy.

Abstract 1820

Poster Board I-846

T cells contribute to the immunomodulatory control of the tumor in patients with monoclonal gammopathies. We previously found that CD3⁺CD8⁺CD57⁺TCRVβ⁺restricted cytotoxic T cell expansions were present in 48% of patients with multiple myeloma (n=221) and conferred a significant favorable prognosis. We now report the presence of these expansions in 70% of patients with Waldenstrom's Macroglobulinaemia (WM) (n=20) with a wide spectrum of the TCRVβ repertoire represented. Previous nucleoside analogue (NA) therapy, known to be associated with an increased incidence of transformation to aggressive lymphoma, significantly influenced the presence of TCRVβ expansions (χ2=11.6; p<0.001) as 5 of the 6 patients without and only 1 of the 14 patients with TCRVβ expansions had received NA. Clonality of CD3⁺CD8⁺CD57⁺TCRVβ-restricted cytotoxic T cells was confirmed by determining the size of the TCRVβ chain CDR3 region and by direct sequencing. We identified differential gene expression by using microarray analysis (Affymetrix GeneChip Human Genome U133 plus 2.0 Arrays) and confirmed the expression of selected genes by real-time qPCR and flow cytometry. Data was analysed by paired moderated t-test and then Gene Set Enrichment Analysis (GSEA) for pathway analysis. Clonal T cells not only had upregulated genes from cytotoxic pathways (granzyme B, perforin and FGFBP2) but also genes which suppress apoptosis, proliferation, cell cycle G1/S transition arrest and T cell activation (RAS, CSK and TOB pathways) indicating anergy which was validated by CFSE tracking of proliferation after antiCD3+antiCD28 stimulation. The current studies provide further evidence for the persistence and relevance of clonal T cells in monoclonal gammopathies.