Avaliação da imunogenicidade da vacina anti-pneumocócica polissacarídica 23-valente em pacientes com lúpus eritematoso sistêmico sob imunossupressão terapêutica

Abstract

Owing to the higher morbimortality due to pneumococcal pneumonia amongst systemic lupus erythematosus (SLE) patients in comparison with the general population, there has been worldwide support by governments and professional organizations for vaccinating this particular patient population against pneumococcal disease in order to tackle this adverse scenario. Nevertheless, few studies with adult SLE patients have examined the antibody response following pneumococcal vaccination, especially among those under immunosuppressive therapy. Thus, in this study we aimed to evaluate the humoral immune response to the 23-valent pneumococcal polysaccharide vaccine (PPSV23) in adult SLE individuals undergoing and not undergoing therapeutic immunosuppression (IS group and non-IS group, respectively). Fifty-four adult SLE patients received one dose of PPSV23 between february 2013 and april 2014, of whom 28 belonged to the IS group and 26 to the non-IS group. The serum levels of immunoglobulin G (IgG) antibodies to seven pneumococcal serotypes were measured by enzime-linked immunosorbent assay from samples collected immediately before and between 4 to 6 weeks after pneumococcal immunization. An adequate serotype-specific vaccine response was defined as a four-fold or greater increase in baseline IgG anti-pneumococcal antibody levels or as a pre-vaccine level < 1.3 µg/mL and post-vaccine &#8805; 1.3 µg/mL (i.e., seroconversion). Each immunized subject should then respond appropriately to at least 70% of the serotypes tested. We secondarily evaluated the fold rise in IgG anti-pneumococcal antibody levels, the two-fold response rate over baseline anti-pneumococcal levels for each specific serotype, and the effect of immunization on lupus disease activity. At baseline, IS group patients were significantly younger, had a more active disease and used a higher dosage of prednisone (median dose = 5 mg/day vs 4.5 mg/day; p = 0.01). There were no differences between the treatment groups in the two- and four-fold increase rate in IgG levels over baseline against each serotype tested. The mean ratio of increase in anti-pneumococcal levels was higher in the non-IS group than in the IS group (6.4 vs 4.7; p = 0.001). A positive seroconversion response was reached by 38.8% of the patients, whereas 29.6% of them responded adequately by the four-fold response criterion, having no significant differences in response rates between the groups. Lupus disease activity remained unchanged in both groups. In sum, the pneumococcal polysaccharide vaccine was poorly immunogenic in this group of adults with SLE, especially those under therapeutic immunosuppression.