Aspects of splenic hypofunction in old age.

The weight of the human spleen decreases in old age. The percentage of erythrocytes with pits observed by interference contrast microscopy was significantly higher in 39 elderly subjects (median 4.2%, range 1.2%-14.6%) than in 34 younger controls (median 1.4%, range 0.6%-6.2%). Further evidence of splenic hypofunction was obtained from 7 elderly people with increased pit counts: the removal from circulation and accumulation into the spleen of heat-damaged autologous erythrocytes was abnormally slow. However, no difference in the spleen area of the same subjects measured by scintillation scanning was observed in comparison with normals. Thus, the weight reduction of spleen in old age is accompanied by a decrease in splenic function.