Increased proliferative response of human peripheral blood lymphocytes to anti-immunoglobulin antibodies in elderly people

Abstract

The proliferative response of human peripheral blood lymphocytes from young adults (average age, 29 years) and from healthy elderly individuals (average age, 78 years) to anti-immunoglobulin antibodies (anti-Ig), phytohemagglutinin (PHA), Concanavalin A (Con A), and pokeweed mitogen (PWM) was measured. Elderly individuals responded better to anti-Ig than young subjects, while young subjects responded better to PHA and PWM. There was no difference in terms of Con A. These results suggest that in terms of lymphocyte responsiveness to PHA and to anti-Ig, elderly subjects have “hyporeactive” thymus-derived or T cells and “hyperreactive” bone marrow-derived or B cells. There was no relationship between the response to anti-Ig in the elderly subjects and serum immunoglobulin levels or the presence of serum autoantibodies. These differences between young and old people may be due to a loss of thymic influence that occurs with age.