Thymus malnutrition

Protein-calorie malnutrition has a devastating effect on the thymolym-phatic system, and very early in the course of malnutrition in infants, the thymus usually shows a pronounced atrophy, followed by that of the spleen and then the rest of the lymph nodes. How these are related to (a) the defect of the cell-mediated immunity which we frequently observe in subjects with parasitic infection and (b) the autoimmune disorders of the heart, the kidneys, and the spleen in subtropical and tropical populations are not immediately apparent, but they arc useful areas for further investigations. 

Simon, in 1845, described the thymus as an early critical barometer of nutrition (Sll) and Hammar (HI) was so impressed by the characteristic lesions produced in the thymus by malnutrition (Jl) that he applied the term accidental involution to describe the atrophied changes produced in the thymus by malnutrition. Of all the thymolymphatic organs the thymus first showed the most pronounced involution in the malnourished individuals, followed by the spleen (A8) and then the rest of the lymphatic organs (.15) (Table 4). 

Children dying from malnutrition have been first noted in 1937 to have had a profound depletion of the thymus gland (V2). This has now been confirmed in several parts of the world (T6, W5). 

The massive atrophied change which takes place first in the thymus followed by the spleen could well explain the marked depressed function of thymus-dependent lymphocytes (T cells)—phytohemagglutinin-responsive cells—in peripheral blood of subjects with protein calorie malnutrition (J6, M18, S6, S12). 

Severe malnutrition generally affects the T cell rather than the B cell compartment. The basis for immune impairment of both children and experimental animals may well be atrophy of the thymus. The thymus is the slowest organ to recover following nutritional repletion (McFarlane, 1977). Severe malnu-... 

In addition, observers have noted that l3nnphocytopenia and thymic atrophy are also characteristic of those suffering from protein-calorie malnutrition. There is growing evidence that those suffering from this deficiency are also zinc deficient. Golden et al, (1977, 1978) were able to increase the size of the thymus and the delayed-type hypersensitivity response of malnourished children by administering zinc. 

Severe depletion of mature T-cells and atrophy of T-dependent areas of lymphoid tissue Significant defects even in mild malnutrition due to extreme sensitivity of thymus gland... 

Nunez, I.N., Maldonado Galdeano, C.M., Carmuega, E., et al. (2012) Effect of a probiotic fermented milk on the thymus in BALB/c mice under non-severe protein-energy malnutrition. British J Nutr 110, 500-508. 

Savino, W. (2002) The thymus gland is a target in malnutrition. Eur J Clin Nutr 56, S46-S49. 

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