Antibody responses to meningococcal polysaccharide vaccine in adults without a spleen.

Asplenic persons are at risk for the development of overwhelming sepsis from certain encapsulated bacteria, including meningococci. Since it is not known if asplenic persons can have antibody responses, this study compared such responses following bivalent groups A and C meningococcal polysaccharide vaccine in 22 asplenic subjects and healthy control subjects. There were no adverse reactions to the vaccine. Antibody responses were measured using a solid-phase radioimmune assay; results were compiled for both seroconversions and changes in mean antibody titers of IgG, IgA, and IgM classes. Subjects who underwent splenectomy for trauma and control subjects with spleens showed a polyclonal antibody response to both vaccine antigens. Those persons who underwent splenectomy for nonlymphoid tumors had nearly as good a response as normal subjects. By contrast, asplenic subjects with lymphoid tumors who had received prior chemotherapy and radiotherapy had poor responses to both antigens. It is concluded that meningococcal vaccine is immunogenic in asplenic persons, with the aforementioned exceptions, and that this vaccine should be routinely administered to such persons.