Specific antibody deficiency with normal immunoglobulin concentration in children with recurrent respiratory infections

© 2013 SEICAP. Background: Response to polysaccharide antigens is a test to evaluate the immunological competence of children with recurrent respiratory infections (RRI) of unknown cause and no other immune system abnormality. In order to detect specific antibody deficiency (SAD), a group of children with RRI without other immunodeficiency were prospectively studied. Methods: We included 20 children (12 male), age range 3-14 years, with six or more annual episodes of respiratory infections (RI); one or more monthly episodes of RI during the winter months; or three or more annual episodes of lower RI. The children were immunised with 23-valent polysaccharide anti-pneumococcal vaccine, and ELISA was used to measure anti-polysaccharide IgG antibody levels for 10 pneumococcal serotypes at baseline (T0), and 45 days (T1) and one year post-immunisation (T2). Post-immunisation response above 1.3. μg/ml for more than 50% of the serotypes was considered normal for children 2-5 years, and for m