Induction by lenalidomide and dexamethasone combination increases regulatory cells of patients with previously untreated multiple myeloma

The bone marrow of myeloma patients is steadily inhabited by a normal-sized pool of functional regulatory T cells irrespectiveof the disease status

“…More recently, thalidomide and lenalidomide have also been shown to increase the frequency and function of Tregs in MM, and lenalidomide, in association with dexamethasone, has been reported to increase Tregs and concurrently decrease the effector functions of T and NK cells. 32 Finally, our data indicate that Tregs neutralization should be considered to maximize the therapeutic effects of immune-based interventions in MM and different strategies are now available to achieve this goal. …”

Contribution of regulatory T cells to immunosuppression and disease progression in multiple myeloma patients

“…We were therefore interested in assessing whether lenalidomide (one of such IMiDs) affects Tregs in MM patients. To our surprise, the administration of lenalidomide in combination with dexamethasone (a corticosteroid) significantly increased the amount of both CD4 + and CD8 + Tregs in MM patients 6 , 7 . Such an increase in immunosuppressive Tregs upon the co-administration of lenalidomide and dexamethasone is paralleled by a decreased in the effector functions of T and NK cells 8 , 9 .…”

Immunological Dysregulation in Multiple Myeloma Microenvironment

“…Accumulation of myeloid derived suppressor cells (MDSC) has been described in the peripheral blood of patients affected by solid tumors [84–86], and only a few reports are focused on MM, including 11 newly diagnosed patients [87], 13 relapsed/refractory patients [88], and 11 MGUS [89–91]. …”

“…Recently, modulation by lenalidomide of regulatory cells, with an immunophenotype overlapping with mo-MDSC, defined as CD33 + CD11b + CD14 − HLADR − , has been reported [89], while in vitro studies exclude a direct effect of lenalidomide or bortezomib in MDSC expansion [88]. On the other hand, in lymphoma-bearing mice, lenalidomide can reduce MDSC numbers and reverts cancer-induced immunosuppression [105].…”