Changes in Immunologic Function

Abstract

Immunologic function is one of the most intensively studied physiologic processes in gerontology, in part due to the explosive growth in all aspects of immunologic research in the past three decades, and to the ease of obtaining immunocytes (lymphocytes, monocytes, and polymorphonuclear leukocytes) for study. There are more fundamental reasons, however, why the study of immunology is particularly relevant to gerontology. Immunologic function declines with age, as do most physiologic functions. Concomitant with this decline in immune function, there is a rise in the incidence of many infections and malignancies with age. There is greater morbidity and mortality associated with common infections in adults over age 65 years. Elderly persons respond less well to protective immunizations against common infections such as influenza and pneumococcal pneumonia. Also intriguing have been observations dating back to the 1930s (described later) linking changes in immune function with changes in the life span of various animal species. An understanding of immunologic changes might be important not only in understanding the aging process, but also in developing potential strategies to prevent some of the morbidity and other changes that occur with age.1,2 This chapter describes changes in the immune system attributed to aging, and gives an overall sense of our understanding of aging and immune function as we near the end of the twentieth century.