Streptococcus pneumoniae is a gram-positive bacteria that causes a variety of infectious diseases in children and adults. More than 90 serotypes of Streptococcus pneumoniae have been identified, based on cell wall polysaccharides.
Immunization with a 23-valent vaccine is recommended for all adults 65 years or older, adults 18 to 64 years of age with chronic diseases, immunocompromised patients, and individuals with asplenia.
Vaccines containing bacterial polysaccharides induce a T-cell independent type II humoral immune response that results in generation of memory B cells and IgG antibodies, which can be protective against bacterial disease. Adults and children older than 2 years are immunized with a nonconjugated polysaccharide vaccine (Pneumovax and Pnu-Immune 23) that contains 23 serotypes (1, 2, 3, 4, 5, 6B, 7F, 8, 9N, 9V, 10A, 11A, 12F, 14, 15B, 17F, 18C, 19A, 19F, 20, 22F, 23F, and 33F), which account for approximately 90% of invasive pneumococcal infections. Three fourths of immune-competent adults and older children form IgG antibodies within 4 to 6 weeks following immunization. Serotype-specific antibodies may persist for up to 10 years following immunization or infection.
Children younger than 2 years have weak immune response to polysaccharide vaccines. They require vaccine prepared from purified polysaccharides conjugated with Corynebacterium diphtheria strain C7 protein to mount a T-cell dependent antibody response.Prevana13 contains 13 serotypes and isapproved for administration to all children between the ages of 6 weeks to 71 months.
Determining the ability of a patient to produce an IgG antibody response to pneumococcal vaccine is included in the workup of suspected humoral or combined immunodeficiencies. A twofold or greater increase in antibody concentration for at least 50% of serotypes after pneumococcal vaccine is consistent with a normal immunological response.
Patients with congenital immunodeficiency diseases may exhibit impaired antibody response to pneumococccal vaccine. Some patients have selective antibody deficiency, which is characterized by recurrent bacterial respiratory infections, decreased or absent antibody response to a majority of the polysaccharide antigens, and normal or increased immunoglobulin levels.
Specimen requirement is a red top tube of blood. Reference ranges are determined for each serotype and reported in ug/mL.
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