Defective mononuclear cell support of erythropoiesis in the elderly

As many as one third of anemic elderly patients have anemia as an isolated finding without demonstrable morphologic abnormality of the marrow, deficiency of hematinic vitamins, or minerals or disease known to cause secondary anemia. These people may have a pathologic process: anemia of senescence. Erythroid cells mature from nonlymphoid mononuclear cells; the maturation process is modulated by lymphokines. When assessed as end products of the humoral or cellular immune system, mononuclear cell function declines with host age. This study tests the hypothesis that mononuclear cell support of erythroid burst formation is defective in elderly subjects. Leukocyte-conditioned medium was prepared from each of five young and five elderly adults. Erythroid bursts from young or elderly adults were grown in culture medium containing leukocyte-conditioned medium from at least three young adults and at least three elderly adults. Erythroid bursts from either young or elderly adults were 1.4-3.0 times more numerous if the leukocyte-conditioned medium derived from a young rather than elderly adult. In addition, when culture medium contained leukocyte-conditioned medium from young adults, only half the elderly adults studied had erythroid bursts equal to those of young adults. These data support the hypothesis that mononuclear cell support of erythropoiesis in the elderly is defective.