[Immunoglobulin and lysozyme concentration in the serum of patients with Down's syndrome]

A study of the immunoglobulin level in the 3 main classes (IgG, IgM and IgA) and lysozymes in the blood serum of 73 patients with Down's disease (from 5 to 20 years of age) showed an increase of IgG in the younger age (up to 7 years) and older groups (over 7 years). The content of IgM was significantly lower in the younger group and did not differ from the control indices in the older group. The level of IgA corresponded to normal indices. The studies demonstrated a marked drop in the lysozyme content. The role of the abnormal system of humoral immunity and reactions of nonspecific defense in the formation of predisposition to the development of infectious diseases in this form of pathology is discussed.