High dose cyclophosphamide preferentially targets naive T (CD45/CD4/RA+) cells in CIDP and MS patients

Introduction: T cells occupy a central role in MS and CIDP pathogenesis. High dose cyclophosphamide's in-vivo cytotoxic-effect on circulating memory and naive T cells is unknown. Method: Three MS and five CIDP patients received cyclophosphamide (200 mg/kg) for refractory disease. Before and after chemotherapy administration, peripheral blood T-cell subsets were determined. Patients underwent serial neurologic evaluations quarterly. Results: Cyclophosphamide uniformly decreased clinical disease activity. Compared to memory T cells, naive T cells were preferentially eradicated. Discussion: Cyclophosphamide effectiveness in autoimmune illness may result from Naive T-cell destruction, as this compartment may be the source of autoreactive lymphocytes. (C) 2007 Elsevier B.V. All rights reserved.