Low frequency of regulatory B-cells and increased CD4+ and CD8+ interferon-γ-producing cells in patients with tropical spastic paraparesis associated with human T-cell lymphotropic virus type

Abstract INTRODUCTION: Tropical spastic paraparesis/HTLV-1 associated myelopathy (TSP/HAM) is a disease caused by human T-cell lymphotropic virus type 1 (HTLV-I) that mainly infects CD4 T cells-for example, those of the CD4+CD25hiFOXP3+ [Treg] phenotype-where it inhibits forkhead box protein P3 (FOXP3) expression and promotes interferon-γ (IFN-γ) expression. However, the role it exerts on regulatory B cells (CD19+CD24hiCD38hi; Breg) is unknown. METHODS: The frequencies of Treg and Breg cells was evaluated and the Th1 profiles were assessed in TSP/HAM patients and healthy control subjects. RESULTS: Low percentages of Breg cells and high production of IFN-γ were observed in patients compared to those in healthy control subjects. CONCLUSIONS: The low percentage of Breg cells in patients and the increase in the frequency of Th1 cells suggest an imbalance in the control of the inflammatory response that contributes to the immunopathogenesis of TSP/HAM.