Immunoglobulin levels and intellectual functioning in the aged.

Significant positive correlations between vocabulary test scores and serum levels of immunoglobulins, IgG and IgM, were obtained for 14 subjects ranging in age from 83-100 years (mean 89.0 years). This positive association with vocabulary scores is a result contrary to data reported by other investigators. The interrelationship between measures of behavior, central nervous system and immunologic function deserve further attention.