Thymulin (Zn-FTS) activity in protein-energy malnutrition: new evidence for interaction between malnutrition and infection on thymic function.

The combined effects of protein-energy malnutrition (PEM) and infection on thymic function evaluated by specific plasma thymulin activity were studied in Senegalese children: 29 hospitalized in Dakar for severe malnutrition and various diseases; 9 infected without sign of severe PEM, living in Dakar; 13 apparently healthy, uninfected, living in Dakar; and 7 apparently healthy, uninfected, living in Paris. Most of the free-living children in Dakar suffered from mild to moderate PEM. The specific thymulin activity (total plasma activity minus the activity recorded after adsorption of the plasma with a monoclonal antithymulin antibody) was almost undetectable in the infected children and was normal only in the children living in Paris. Such activity might be decreased by moderate and severe PEM and severe malnutrition may not be the only underlying cause of depressed level of thymulin in malnourished children from the Third World. Concurrent infections are important factors.