A declining lymphocyte count is an apparent indicator of death, according to researchers from the National Institute on Aging's Gerontology Research Center. In a 16- year retrospective study, researchers noted a progressively declining lymphocyte count that began 3 years prior to death. The study involved 105 men who had no significant clinical disease when they entered the study. The decline in lymphocytes was not associated with age at the time of death or with the cause of death. Researchers hypothesize that a triggering event causes physiological stress, which affects lymphocyte numbers [Special Report on Aging 1988-1989. Washington, DC: National Institute on Aging; 1989:2].