Serum and salivary IgA levels in normal subjects: comparison between tonsillectomized and non-tonsillectomized subjects.

Serum IgA and secretory IgA (SIgA) were determined in 1,000 apparently healthy subjects; 274 were tonsillectomized. Four groups were identified in this study: (1) 0.3% of subjects had no serum IgA and SIgA; (2) 1.6% of subjects showed partial serum and SIgA deficiency; (3) 27.4% of individuals were tonsillectomized and had partial serum IgA deficiency but normal SIgA, and (4) 71.4% were normal, both with respect to serum IgA and SIgA. There results stress the relatively high incidence of IgA deficiency in the normal population and confirm the role of the tonsils in maintaining serum IgA levels.