We studied 17 immunodeficient children 4-14 years old (9 with hypogammaglobulinemia, 8 with selective IgA deficiency) all having chronic lung suppurations. The highest rate of S.pneumoniae colonization was in children with IgA deficiency (up to 50%) with noncapsular H.influenzae found in 43%. Antibody levels to S.pneumoniae capsular polysaccharides, C-polysaccharide, protein antigens were studied in serum, saliva and bronchoalveolar lavage fluid by ELISA; IgG subclasses in serum - by radial immunodiffusion. All patients had absent or very low levels of pneumococcal IgA-antibody in secretions. In spite of the presence of serum IgG-antibody (even their high levels in selective IgA deficiency) all children had severe suppurations indicating the major role of local immune response in bacterial clearance from the respiratory tract. It also suggests that serum IgG antibodies do not pass in sufficient quantity into bronchial secretion due to a peribronchial fibrosis. Low serum IgG-antibody levels were found in children with hypogammaglobulinemia, however two patients with combined IgA - IgG subclass deficiency (IgA plus IgG1, IgG3, IgG4 and IgA plus IgG4) had almost normal serum antibody level probably due to the relation of pneumococcal antibody to IgG2. Clinical data indicate that different rate of hypogammaglobulinemia expression may explain the diversity in manifestations of primary humoral immunodeficiency.
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