title: Increased serum opsonic activity and antibody concentration in patients with sickle cell disease after pneumococcal polysaccharide immunization.
abstract: Opsonic defects have been reported in unimmunized patients with sickle cell disease. We found significant increases (P less than 0.001) in serum opsonic activity, measured by a radiolabeled bacterial uptake assay, and in type 7 pneumococcal polysaccharide antibody concentration in 17 such patients 2 years of age or older after pneumococcal polysaccharide immunization. All 17 patients and six healthy controls achieved a type 7 antibody concentration of more than 300 ng antibody nitrogen per milliliter, believed to be the protective level of antibody in vivo. Six patients with sickle cell disease less than 2 years of age did not have a significant increase in type 7 antibody concentration after immunization. Only three of these six patients achieved a postimmunization type 7 antibody concentration exceeding 300 ng Ab N/ml. Overall, 16 of 23 patients with sickle cell disease (70%) had a twofold or greater increase in type 7 antibody concentration, and 13 of these (81%) had a corresponding increase in opsonic activity (P less than 0.001). Thus most patients who responded to pneumococcal polysaccharide immunization had a concurrent increase in opsonic activity in vitro.
mesh_terms: D000293:Adolescent; D000367:Age Factors; D000755:Anemia, Sickle Cell / Q000150:complications / Q000276:immunology*; D000907:Antibodies, Bacterial / Q000276:immunology*; D001428:Bacterial Vaccines / Q000008:administration & dosage*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007114:Immunization; D007223:Infant; D008297:Male; D009895:Opsonin Proteins / Q000276:immunology*; D011008:Pneumococcal Infections / Q000517:prevention & control; D022242:Pneumococcal Vaccines; D013296:Streptococcus pneumoniae / Q000276:immunology
chemical_list: D000907:Antibodies, Bacterial; D001428:Bacterial Vaccines; D009895:Opsonin Proteins; D022242:Pneumococcal Vaccines