title: Flow cytometry based enumeration and functional characterization of CD8 T regulatory cells in patients with multiple myeloma before and after lenalidomide plus dexamethasone treatment.
abstract: BACKGROUND
  Multiple myeloma (MM) is a malignancy of plasma cells frequently associated with immune abnormalities. Several studies have confirmed that in MM immune deregulation can be mediated by increased numbers of CD4 T regulatory (Treg) cells, and these cells were also associated with poor outcome. In the present study, we aimed to study CD8 Treg cells before and after lenalidomide plus dexamethasone (len-dex) treatment in MM patients.
  
  
  METHODS
  Using flow cytometry, we enumerated and assessed suppressive function of CD8 Treg cells in 16 MM patients before and after len-dex treatment.
  
  
  RESULTS
  Numbers of CD8 Treg cells (CD8+CD25hi+FoxP3+) (P<0.01) were significantly increased in MM patients (before treatment) compared to healthy donors. However, no significant changes were observed in CD4 and CD8 T cells. A significant increase in CD8 Treg cells was observed after len-dex treatment compared to pre-treatment but no significant difference was observed in CD4 and CD8 T cells. Proliferation assay data showed that CD8 Treg cells inhibited proliferation of CD4 T cells and IFN-γ secretion in a concentration dependent manner. Suppressive activity of CD8 Treg cells did not differ significantly between healthy donors, untreated and len-dex treated MM patients. A significant abnormal level of IL-10 was observed from proliferation assays of untreated and len-dex treated MM patients compared to healthy donors (P≤0.03).
  
  
  CONCLUSIONS
  Using flow cytometry, we have shown that suppressive CD8 Treg cells are increased in MM patients and len-dex treatment is unable to control these suppressive CD8 Treg cells. © 2013 Clinical Cytometry Society.
authors.affiliation: Babak Myeloma Group, Department of Pathological Physiology, Faculty of Medicine, Masaryk University, Brno, Czech Republic; Department of Experimental Biology, Faculty of Science, Masaryk University, Brno, Czech Republic.
authors.forename: Karthick Raja Muthu
authors.initials: KR
authors.lastname: Raja
authors.forename: Martin
authors.initials: M
authors.lastname: Plasil
authors.forename: Lucie
authors.initials: L
authors.lastname: Rihova
authors.forename: Jana
authors.initials: J
authors.lastname: Pelcova
authors.forename: Zdenek
authors.initials: Z
authors.lastname: Adam
authors.forename: Roman
authors.initials: R
authors.lastname: Hajek