The effect of ranitidine on antibody responses to polysaccharide vaccines in patients with B-cell chronic lymphocytic leukaemia.

OBJECTIVES To analyse the effects of ranitidine treatment on vaccination induced antibody responses in patients with chronic lymphocytic leukaemia (CLL). METHODS Fifty CLL patients were vaccinated with tetanus conjugated Hib vaccine and a 23-valent pneumococcal polysaccharide vaccine with (n = 25) or without (n = 25) ranitidine treatment in a matched case--control setting. Anti tetanus toxoid (TT), anti-Hib and anti-pneumococcal antibody levels were determined before and after vaccination. Additionally, cytokine levels were assessed in patients treated with ranitidine. RESULTS Vaccination-induced increases in anti-Hib and anti-TT antibody levels were higher in the ranitidine group compared with the control group. Anti-pneumococcal antibody responses were not improved by administration of ranitidine. Higher levels of IL-18 were found in patients treated with ranitidine compared with healthy controls. Levels of IL-6, IL-8, IL-18, RANTES, IP-10, sVCAM-1 and sICAM-1 were within normal ranges and did not change during ranitidine treatment. CONCLUSION Ranitidine treatment improves vaccination-induced T-cell dependent antibody responses in patients with CLL but has no beneficial effect on the response to vaccination with unconjugated polysaccharide antigens.