In addition, vital signs, physical examination and laboratory results should not have exhibited any evidence of diseases such as psychiatric or cognitive disturbance, cirrhosis or advanced liver disease. Patients agreed not to take any herbal medicine or medication that was contraindicated with VPA for the duration of the study. VPA (valproate sodium; Epival®, Abbott Laboratories, Quebec, Canada) was administered at an initial dose of 500 mg on the first evening and increased to 500 mg twice a day (bid) per os over 1–7 days according to clinical tolerance. VPA serum concentration was assessed in all participants 12 h after the last dose at CHIR-99021 purchase week 1

and every 4 weeks thereafter. If the participant had not reached the therapeutic VPA concentration at the end of the first week, an unscheduled visit was arranged and the drug level retested. The dose was adjusted to the therapeutic range (50–100 μg/mL), which is used in patients with seizures. Venous blood samples were drawn into ethylenediaminetetraacetic acid (EDTA) tubes and processed within 1 h of collection as previously described [16]. Peripheral blood mononuclear cells (PBMC) were separated by Ficoll-Hypaque density centrifugation, washed and re-suspended in phosphate-buffered saline containing heat-inactivated fetal calf serum and then stored in liquid nitrogen until used. CD4 and CD8 T cells were enumerated by flow

cytometry, and plasma viral load was measured using the Roche Amplicor Assay HKI-272 manufacturer (Roche Diagnostics,

Mississauga, Canada) as previously described [16]. A quantitative limiting-dilution culture assay was used to determine the frequency of cells harbouring replication-competent virus as previously described [17]. In brief, PBMC were resuspended at a concentration of 106 cells/mL in RPMI-1640 medium (Sigma, St Louis, MO) supplemented with 10% heat-inactivated fetal calf serum, penicillin (50 U/mL), streptomycin (50 mg/mL), L-glutamine (2 mM), HEPES buffer (10 mM), and recombinant human interleukin-2 (Hoffmann-La Roche, Nutley, NJ) (100 U/mL). Six fivefold dilutions of PBMC were cultured starting at a concentration of 25 × 106 PBMC. A CD3/CD8-bispecific monoclonal antibody, which selectively depletes CD8 T cells while activating CD4 T cells, was added at a final concentration of 1 mg/mL. Cell cultures were Urease incubated at 37°C in a humidified 5% CO2 atmosphere and maintained for a 21-day period with medium changes twice a week. Supernatants were collected weekly prior to the medium change, for the measurement of HIV-1 p24 antigen using an enzyme-linked immunosorbent assay (Vironostika, Bio Mérieux, France). The number of infectious units per log10 billion (IUPB) PBMC was calculated from the pattern of positive wells using the method of maximum likelihood. IUPB were assessed at baseline and at weeks 16 and 48. Quantitative data were summarized using the mean, median, the standard deviation and the range.