Immunosuppression impairs response to pneumococcal polysaccharide vaccination in patients with inflammatory bowel disease.

Objectives: The treatment of inflammatory bowel disease (IBD) often includes immunosuppressive medications, which may increase the risk of vaccine-preventable illnesses. We aimed to assess the impact of immunosuppression on immune responses to pneumococcal vaccination in patients with IBD.

Methods: The study design consists of a prospective controlled clinical trial. This study was carried out at a tertiary-care IBD clinic. The subjects for the study belonged to one of the following three groups: adult patients with IBD on combination TNF-blockers and immunomodulators (Group A), those without immunosuppressive therapy (Group B), and age-matched healthy controls (Group C). The treatment consisted of immunization with 23-valent pneumococcal polysaccharide vaccines (PSVs). The main outcome was immune response for five serotypes defined as a twofold or greater increase from pre-vaccination titers and > or =1 microg post-vaccination titer.

Results: Sixty-four subjects participated in the study: 20 in Group A, 25 in Group B, and 19 in Group C. Pre-vaccination titers were similar among the three groups. Vaccine responses were lower in Group A than in Group B (P< or =0.01 for four out of five antigens) and Group C (P<0.01 for all five antigens). Overall vaccine response was seen in 45, 80, and 85% of Groups A, B, and C (P=0.01), respectively.

Conclusions: Immune response to PSV-23 is impaired in Crohn's disease (CD) patients on combination immunosuppressive therapy but is normal among non-immunosuppressed patients. Given the unpredictable likelihood for immunosuppressive therapy, newly diagnosed patients with IBD should undergo vaccination before the initiation of immunosuppressive therapy.