Secretory immunity and immunodeficiency.

1) Certain selective IgA-deficient subjects are capable of synthesizing functional secretory antibodies (s-IgM or s-IgA class) to indigenous oral microorganisms. 2) The presence or absence of these secretory antibodies in saliva can be correlated with the extent of caries involvement. 3) Lysozyme activity is significantly increased in saliva from immune deficient subjects though no correlation can be made with caries experience.