Forty patients met the criteria and gave their written informed consent for participation in this study. All the participants were on

regular haemodialysis three times per GS 1101 week for 4 h by low-flux dialyser with polysulfone/polyamide membranes, reverse osmosis purified water and bicarbonate-containing dialysate. The 40 participants were randomized into two equal groups to receive one dose (0.5 mL) of intramuscular Td vaccine (made by Razi Vaccine & Serum Research Institute, Karaj, Iran) supplemented with either levamisole (100 mg) or placebo daily, 6 days before and 6 days after vaccination. This dosage was already shown to be effective in inducing seroprotection against HBV in haemodialysis patients with minimal side effects.[10] Using Random Allocation Software,[11] blocked randomization with a fixed block size of 4 was done by one of the investigators who had no clinical

involvement in the study. Levamisole and placebo tablets were provided by Shiraz School of Pharmacy in prepackaged bottles numbered for each patient according to the randomization sequence. Each patient was given an order number to receive the corresponding levamisole or placebo bottle. Levamisole and placebo tablets were completely similar in shape, size, weight, colour and taste. Patients, clinical investigators and laboratory staff were all blinded to the treatment assignment. Clinical staff inspected adverse events at each haemodialysis session. For all the enrolled patients, the anti-tetanus IgG serum levels were measured at baseline see more and also at 1 and 6 months after vaccination. Before the start of haemodialysis session, 10 cc blood samples were obtained from the patients’ arms used for haemodialysis access. The serum samples were separated by centrifugation at 3000 g/min for 5 min and stored at −70°C

until analysis. Anti-tetanus Amobarbital IgG levels were measured by a highly sensitive ELISA kit (IBL International GmbH, Hamburg, Germany). The cut-off value for protective level of anti-tetanus IgG was set at 0.1 IU/mL, based on the EPI Program of WHO.[2] The intra- and inter-assay coefficients of variation were 2.1% and 5.5%, respectively. Statistical analyses were done by the SPSS base 15 (SPSS Inc., Chicago, IL, USA) statistical software package. Quantitative data were compared between the two groups using Mann–Whitney U-test; categorical data were compared using chi-squared or Fisher’s exact tests. P-values of less than 0.05 were considered statistically significant. The primary outcome was the rate of the patients who developed protective anti-tetanus IgG levels 1 and 6 months after vaccination. This study was started in March 2008 and was completed in November 2008. As demonstrated in Table 1, the baseline demographic and laboratory characteristics of the patients were similar in the two groups.