Clinical evaluation of VPA treatment. (A) Proviral load in 19 HAM/TSP patients among whom 8 discontinued the treatment before the end of the study. Genomic DNA was extracted at month 0 (M0), month 12 (M12), and month 21 (M21) using Trizol (Sigma-Aldrich), and HTLV-1 proviral load was quantified using a real-time TaqMan PCR method, as described previously.¹⁰  The value for the HTLV-1 proviral load was reported as the [(HTLV-1 average copy number)/(albumin average copy number)] × 2 × 10³ and expressed as the number of HTLV-1 copies per 10³ cells. (B) Baseline demographic characteristics of the patients and comparison of mean neurologic scores between M0 and M24 or last visit before treatment discontinuation. (C) Patients withdrawn over the 24 months of the study.