IL1B and plexiform neurofibroma: Different molecules have been implicated in the recruitment of different cell types (mast cells, macrophages, T cells, dendritic cells) to neurofibromas: CCL2/CCL12/CCR2 (43); CSF1 (44); CXCL10/CXCR3 (45); IL-1b (23); IL-6 (46); and KITLG (SCF) (47, 48).