Immunogenicity of pneumococcal polysaccharide vaccine in adult systemic lupus erythematosus patients undergoing immunosuppressive treatment

Abstract

Objective To evaluate the immunogenicity of the 23-valent pneumococcal polysaccharide vaccine (PPSV23) in adult systemic lupus erythematosus patients undergoing (IS group) and not undergoing (non-IS group) immunosuppressive treatment. Methods In this prospective open-label study from February 2013 to April 2014, 54 patients had blood samples collected immediately before PPSV23 immunization and 4–6 weeks thereafter for the ELISA measurement of IgG antibody levels against seven pneumococcal serotypes. Positive vaccine response for each serotype was defined as a four-fold or greater antibody response over baseline levels or as a post-vaccine anti-pneumococcal IgG level ≥1.3 µg/ml when baseline values were <1.3 µg/ml. Patients should have responded appropriately to ≥70% of the tested serotypes. We also calculated the mean ratio of post- to pre-vaccination anti-pneumococcal IgG levels. Results Twenty-eight patients were classified into the IS group and 26 into non-IS group. The median dose of prednisone at baseline was ≤5 mg/day in both groups. Serotype-specific vaccine response rates were not significantly different between the groups. Less than 40% of patients responded adequately by both vaccine response criteria, being numerically lower among IS patients. The mean ratio of increase in anti-pneumococcal levels was 6.4 versus 4.7 ( p = 0.001) in non-IS and IS groups, respectively. Conclusion The vaccine was poorly immunogenic, especially among adult systemic lupus erythematosus patients under immunosuppressive therapy.