MDSCs: friend or foe in systemic lupus erythematosus

Meyoid derived suppressor cells(MDSCs)are heterogeneous myeloid cell populations that expand in pathological conditions such as cancer,autoimmunity,and infection;these cells are also known to exert strong immunosuppressive effects on primitive Tcell responses.1 MDSCs are derived from myeloid progenitors and are arrested at an immature phase of differentiation.In mice,normal bone marrow contains~20–30%cells exhibiting the MDSC phenotype.2 In contrast,a very low number of MDSCs are found in naive spleens(2–4%),and these cells are completely absent in lymph nodes.