CD4 and myeloid sarcoma: More recently, the realization that small subsets of (both CD4+ and CD8+) T cells can also express low levels of CD20 (referred to as CD20dim), and that these cells are also depleted with aCD20 (26, , , –30), has raised an alternate (though not mutually exclusive) possibility, that the ability of aCD20 agents to limit relapsing MS disease activity may in part be mediated by direct removal of pathogenic T cells expressing CD20.