CD4 and myeloid sarcoma: Th17 cells can form immune synapses with oligodendrocyte progenitor cells (OPCs) and axons and induce a partially reversible intra-axonal calcium influx, but therapies targeting solely CD4+ T cells (e.g., via a monoclonal antibody against the p40 subunit of IL12 and IL23) are inefficient in MS [94,95,96].