Turkish journal of haematology : official journal of Turkish Society of Haematology 2018 03 28() doi 10.4274/tjh.2018.0022
Plasma cell dyscrasias (PCD) are disorders of the plasma cells having in common the production of a monoclonal M-protein. They include a spectrum of conditions which may represent a natural progression of the same disease from monoclonal gammopathy of unknown significance (MGUS), to asymptomatic and symptomatic multiple myeloma and plasma cell leukemia and Waldenström’s macroglobulinemia (WM). In PCD the immune system is actively suppressed through the secretion of suppressive factors and the recruitment of immune suppressive subpopulations. In this study, we examined the expression of two subpopulations of cells with immunosuppressive activity: the monocytic-myeloid derived suppressor cells (MDSCs) and monocytes expressing latency-associated peptide (LAP) in patients with different PCD, and in healthy volunteers. Interestingly, we observed a hierarchical correlation between disease activity and the presence of monocytes with immunosuppressive activity. These results suggest that MDSCs and monocytes expressing LAP have diverging roles in PCD and may perhaps serve as biomarkers of tumor activity and bulk.