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Immature circulating lymphocytes in severely malnourished Guatemalan children
G T Keusch1, J R Cruz, B Torun
1Division of Geographic Medicine, New England Medical Center, Boston, MA 02111.
Insights
Severe malnutrition in children can impair immune function, specifically T-cell activity. Treatment with thymosin may help restore immune responses in malnourished individuals.
Area of Science:
- Immunology
- Pediatric Nutrition
- Global Health
Background:
- Protein-energy malnutrition significantly impacts immune system development and function in children.
- Peripheral blood lymphocyte E-rosette formation is a marker of T-cell activity.
- Previous studies indicated uniform depression of E-rosettes in severely malnourished children globally.
Purpose of the Study:
- To assess T-cell function, measured by E-rosette formation, in severely malnourished Guatemalan children.
- To investigate the potential role of thymosin in modulating T-cell activity in malnourished children.
- To explore specific nutrient deficiencies contributing to immune dysfunction in protein-energy malnutrition.
Main Methods:
- Quantified the percentage of peripheral blood lymphocytes forming E-rosettes in 33 severely malnourished children and two control groups.
- Compared E-rosette percentages between malnourished and mildly growth-retarded children.
- Incubated lymphocytes from malnourished children with thymosin fraction 5 in vitro to assess dose-dependent effects on E-rosette formation.
Main Results:
- Severely malnourished children showed lower mean E-rosette percentages compared to mildly malnourished children, with significant overlap.
- Unlike previous reports, not all severely malnourished patients exhibited decreased E-rosettes, suggesting specific nutrient defects.
- In vitro thymosin administration dose-dependently increased E-rosette percentages in lymphocytes from malnourished children.
Conclusions:
- Immune dysfunction in protein-energy malnutrition may be linked to specific nutrient deficiencies affecting T-cell function.
- The presence of thymosin-responsive T-cells suggests potential therapeutic benefits of thymosin administration in malnourished individuals.
- Further research into targeted nutrient supplementation and thymosin therapy is warranted for improving immune function in malnourished populations.
Abstract:
The percentage of peripheral blood lymphocytes forming rosettes with sheep erythrocytes (E-rosettes) was determined in 33 severely malnourished Guatemalan children, and in two groups of clinically well but mildly growth retarded children from the same environment. Mean E-rosettes in the acutely ill patients was lower than the value observed in the mildly malnourished children, although there was considerable overlap between groups. These data differ from previously published studies of severely malnourished children from other parts of the world in that not all patients had decreased values for E-rosettes, in contrast to the uniform depression reported by others. As all patients were clinically similar, the results suggest that there may be specific nutrient defects associated with protein-energy malnutrition that particularly affect immune function. In addition, in vitro incubation of lymphocytes from the acutely malnourished children with the thymic factor, thymosin fraction 5, increased the percentage of E-rosettes in a dose-dependent fashion. These data suggest that immature, thymosin-responsive T cells are present in circulation. It is possible that in vivo thymosin administration may be beneficial for malnourished individuals.