Antibody responses to pneumococcal and hemophilus vaccinations in splenectomized patients with hematological...

In this study we addressed the question of whether an underlying hematological malignancy may affect the immune response to vaccination against bacterial polysaccharide antigens (e.g. Haemophilus influenzae type b, Streptococcus pneumoniae) in splenectomized patients. Between 1993 and 2003, 44 splenectomized adults from the outpatient clinic for infectious diseases were prospectively included in the study: 23 patients suffered from hematological malignancies (HM) and had undergone splenectomy; 21 were splenectomized following trauma (T) and served as the control group. Each patient received an intradeltoid injection with 0.5 ml of a single lot of a 23-valent pneumococcal polysaccharide vaccine, and 0.5 ml of a polyribosyl ribitol phosphate capsular polysaccharide vaccine of H. influenzae type b (Hib) into the opposite arm. Blood samples for determination of pneumococcal and Hib antibodies were taken prior to vaccination and again 6-8 weeks later. In assessing responses to the 23-valent pneumococcal polysaccharide vaccine, we found significant differences in antibody titer increase between the HM and T groups (median IgG increase 1.27 [0.7; 2.39] vs. 3.9 [2.1; 15.3], P < 0.001; and median IgM increase 1.33 [1.0;2.67] vs. 5.25 [2.3; 7.78], P < 0.001). In the HM group, only 8/23 and 6/23 showed a titer increase of twice or more the base value for IgG and IgM respectively, whereas in the trauma group an adequate response was shown by 16/21 and 16/20 respectively. Patients with splenectomy and hematological malignancies responded poorly to the 23-valent polysaccharide vaccine. Response to the conjugated Hib vaccine was slightly better, but still significantly lower than in individuals with posttraumatic splenectomy. Data suggest that vaccination response to the polysaccharide vaccines should be evaluated at least in the high-risk group.