Studies on salivary gamma A in agammaglobulinaemia.

Sera and saliva from nine adult subjects with acquired agammaglobulinaemia and from two individuals with a selective absence of γA were studied for γA and secretory γA content. In all subjects, except for one (B.Cr.), secretory γA was detected in saliva when γA was demonstrable by radial diffusion in serum, and salivary secretory piece alone was found in the absence of serum γA. Saliva B.Cr. contained both γA and free secretory piece, whereas the serum from this patient appeared to lack γA. However, when tested by quantitative complement fixation, a small amount of serum γA was detected. Chromatographic separation and subsequent immunological testing of saliva B.Cr. revealed the presence of secretory γA, secretory piece, and a small amount of serum-type γA. Severity of sinopulmonary infections in these subjects did not correlate with the presence or absence of secretory γA. These observations further substantiate that the production of serum and secretory γA is controlled by similar mechanisms, and that a quantitative defect in secretory γA production does not by itself account for the presence of sinopulmonary disease.