Influenza virus vaccination and booster in B-cell chronic lymphocytic leukaemia patients

Background: Influenza vaccination is recommended for patients with B-cell chronic lymphocytic leukaemia (CLL). Because response rates are often low, we decided to evaluate antibody response to single and booster vaccinations with influenza A and B virus vaccine in these patients. Methods: Twenty patients with B-CLL received two subunit virus vaccine injections 21 days apart. Antibody titres were determined before and 21 days after the single and booster vaccinations. The serological response was expressed using the following criteria: (1) response rate, i.e. the proportion of subjects with at least a 4-fold titre increase; (2) the protection rate, i.e. the proportion of subjects exceeding the threshold of 100 (influenza A) or 200 (influenza B); and (3) the mean fold increase (MFI), i.e. the difference between the log-adjusted geometric mean titres of pre- and post-vaccination sera. Results: Response rates were 5% for influenza A and 15% for B after the single vaccination and 15% for A and 30% for B after the booster vaccination. Protection rates were 0% for influenza A and 25% for B after the single vaccination; they were 5% (H1N1) and 10% (H3N2) for influenza A and 30% for B after the booster. The MFI+/-S.D. (range) after the booster vaccination was 0.26+/-0.33 (0-1.00), 0.17+/-0.34 (0-1.00) and 0.35+/-0.34 (0-1.20) for H1N1, H3N2 and influenza B, respectively. Conclusion: In this study with B-CLL patients, immune response to influenza vaccination was poor. Thus, single and booster vaccinations with influenza virus vaccine do not appear to be of great value to patients with B-cell CLL.