Alterations in Na⁺, K⁺ and Ca²⁺ transport in erythrocytes of patients with carcinomas of the head and neck: possible role of mild anaemia and cell age

1. Rates of erythrocyte Ca²⁺ inward transport, activities of erythrocyte Ca²⁺-adenosine triphosphatase, Na⁺, K⁺ pump, Na⁺-K⁺ co-transport and Na⁺-Li⁺ exchange, and erythrocyte Ca²⁺, K⁺ and Na⁺ contents have been determined in patients with carcinomas of the head and neck.

2. Decreases in Ca²⁺ inward transport and Na⁺-K⁺ co-transport activity, and increases in erythrocyte Ca²⁺ and K⁺ contents, were observed.

3. The more pronounced changes found in advanced carcinoma stages proved to be related to a 50% incidence of a mild anaemia of chronic disease in patients with carcinoma stages T₃ and T₄.

4. ‘Young’ (light) erythrocytes from healthy donors obtained by density centrifugation showed modifications in Na⁺ transport and K⁺ content similar to those seen in the patients.

5. It is concluded that the decrease in Na⁺-K⁺ co-transport activity, as well as the elevated K⁺ content and the lowered mean corpuscular haemoglobin content, but not the disturbances in Ca²⁺ homoeostasis, in erythrocytes of patients with carcinomas of the head and neck are most probably due to the occurrence of a mild anaemia of chronic disease in advanced carcinoma stages, associated with a reduction in mean erythrocyte age.