FCER2 and myeloid sarcoma: This broad mRNA immunophenotype included features — CD19+, PTPRC (CD45)+, FCER2 (CD23)lo, CR2 (CD21)lo, ITGA4 (VLA-4)+, ITGAL (LFA-1)+, TLR4 (CD284)+, CD5int — consistent with pro-inflammatory GM-CSF+ B cells described in MS (103), which are closely related but not identical to innate response activator B cells in mice (104).