Reference Patients/controls evaluated Samples tested Method used in Treg evaluation Tregs frequency Functional studies Impact on prognosis Prabhala et al. [5 ] MGUS Isolated PBMC CD4+ FoxP3+ Decreased Unable to suppress anti-CD3-mediated T-cell proliferation Not evaluated Beyer et al. [6 ] MGUS Isolated PBMC CD4+ CD25+ + cells) Increased in MM versus MGUS (trend without statistical significance) Strong inhibitory function Not evaluated Feyler et al. [7 ] MGUS Isolated PBMC and BM CD4+ CD25+ FoxP3+ Increased in PBMC but not in BM Not evaluated Correlation with disease burden (paraprotein) Gupta et al. [8 ] MM Isolated PBMC CD4+ CD25+ CD127− FoxP3+ + cells) Reduced in untreated which increased after treatment with lenalidomide Able to inhibit proliferation of CD4+CD25-T-cells Increase of Tregs in responding patients to therapy; decrease correlates with ISS I + II Muthu Raja et al. [9 ] MGUS PB/BM whole CD4+ CD25+ CD127- CD45RA+/− Increased in MM but not in SMM and MGUS Able to inhibit the proliferation of CD4+ T-cells and the secretion of IFN- Correlation with adverse clinical features (hypercalcemia, lower normal PC, and IgA subtype); no correlation with ISS; predict time to progression; MM patients with ≥5% of Tregs had inferior time to progression Giannopoulos et al. [10 ] MM Isolated PBMC CD4+ CD25+ Increased Not evaluated Correlation with shorter overall survival Foglietta et al. [11 ] MM Isolated freshly PB and frozen BM CD4+ CD25+ Similar Effective suppressor function No correlation with the pattern of BM infiltration Present study MM PB CD4+ CD25− Similar Effective suppressor function No correlation with laboratory and clinical variables; no correlation with outcome
