AGEING IN HUMAN RED CELLS 



P. L. MOLLISON 



Medical Research Councils Blood Transfusion Research Unit, 

 Postgraduate Medical School of London 



Ageing in red cells suggests at least three processes, all of 

 which may be quite unrelated. First, there is the transition 

 from characteristics displayed by red cells in infancy to those 

 displayed by the same cells in adult life; secondly, there are 

 changes occurring during the life-span of individual red cells; 

 and thirdly, there are changes which occur when red cells are 

 stored outside the body. 



It has been shown that the red cells of newborn infants 

 differ in several respects from those of adults; for example, 

 they are larger and contain a considerable proportion of 

 foetal haemoglobin. It seems probable that the character- 

 istics of the cells of newborn infants reflect changes during 

 the evolution of the species or, in some cases, represent 

 adaptations to foetal life; for example, the weakness of the 

 A antigen at birth may help to protect the group A infants 

 against the A antibody which may cross the placenta from its 

 mother's circulation. A true age change observed in red cells 

 is the weakening of blood group receptors in elderly people as 

 compared with young adults. However, the kind of ageing 

 for the study of which red cells are particularly well fitted is 

 the kind occurring within the life-span of a given population of 

 red cells. 



The life-span of red cells in many species has been exten- 

 sively studied in the past 20 years. The most direct evidence 

 has been obtained from experiments in which red cells formed 

 during a limited period of time are labelled. For example, if 

 radioactive iron is injected into dogs the iron is incorporated 

 into newly formed haemoglobin. Provided that the animal is 

 given an adequate amount of non-radioactive iron, radioactive 



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