CD4 and myeloid sarcoma: Extending idiotope driven T–B collaboration to humans, we have previously demonstrated that human leukocyte antigen (HLA)-DR restricted CD4+ T cells from blood and CSF of MS patients can recognize multiple idiotopes within the complementarity determining region 3 (CDR3) and mutated framework (FW) regions on autologous CSF IgG (31–33), showing that MS patients have a repertoire idiotope-matched T–B cell pairs.