Levamisole treatment enhances protective antibody response to hepatitis B vaccination in hemodialysis patients

Hemodialysis shows a high risk for hepatitis B infection, and hepatitis B virus (HBV) vaccination has now become a routine procedure. Unfortunately, 40% to 50% of hemodialysis patients do not have adequate protective antibodies against the HBV vaccination which is thought to be due to depressed cell mediated immunity. Levamisole has been reported to stimulate depressed T-cell activity and enhance B lymphocyte function and restore delayed hypersensitivity reactions in immune-depressed patients. We studied the effects of levamisole, an immunomodulatory agent, on the protective antibody response of hemodialysis patients to the HBV vaccination. Our hemodialysis patients with negative anti-HBs antibody routinely received 40 microg doses of recombinant HBV vaccine intramuscularly at 0, 1, and 6 months, and we followed serum anti-HBs levels. Patients with a serum antibody level of >10 mIU/ml were considered as responders. Study groups were classified as follows. Group 1 was comprised of 96 chronic hemodialysis patients with negative anti-HBs and HBV core antibody (52 male, 44 female, mean age of 45 +/- 15 years and mean hemodialysis duration of 46 +/- 40 months) who received HBV vaccination; 55 patients (57%) were found to be responders. Group 2 was comprised of 19 randomly selected patients who had never received hepatitis B vaccine (13 male, 6 female, mean age of 42 +/- 14 years, mean duration of hemodialysis 31 +/- 27 months) and who were started on an HBV vaccination protocol with levamisole per os 80 mg after each hemodialysis session for 4 months and followed up on serum anti-HBs levels. Seventeen of the patients completed this levamisole treatment. Fourteen of the 17 patients had the levels of the protective serum antibody indicating a higher response rate when compared with patients who did not receive levamisole (82% versus 57%, respectively, p < 0.05). Group 3 was comprised of 19 patients randomly selected from persons who did not respond to previous vaccination programs (10 male, 9 female, mean age of 51 +/- 14 years, mean duration of hemodialysis 41 +/- 31 months). A second HBV vaccination program was started with the same levamisole protocol. In this group, 18 patients completed this treatment model. Fourteen of them responded to the vaccination model. In Group 4, a second HBV vaccination program was applied without levamisole to 20 randomly selected persons who did not respond to the previous routine vaccination program (12 male, 8 female, mean age of 53 +/- 17 years, mean duration of dialysis 51 +/- 38 months). Only 3 of them responded to a second vaccination program. Comparing Group 3 with Group 4, there was a higher responder rate to HBV vaccination (77% versus 15%, respectively, p < 0.0001). These results show that levamisole treatment increases the response rate to the first HBV vaccination and of the previously unresponsive cases by modulating possible cellular immune response.