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Depressed immune response to tetanus in children with vitamin A deficiency
R D Semba1, Muhilal, A L Scott
1Dana Center for Preventive Ophthalmology, Wilmer Institute, Baltimore, MD 21205.
Insights
Mild vitamin A deficiency in children impairs immune response. Supplementation with vitamin A significantly improved immune response to tetanus immunization in both healthy and vitamin A-deficient children.
Area of Science:
- Nutritional Immunology
- Pediatric Infectious Diseases
- Micronutrient Deficiencies
Background:
- Vitamin A deficiency is a prevalent public health issue, particularly in developing countries.
- Subclinical vitamin A deficiency can compromise immune function, increasing susceptibility to infections.
- Assessing immune status is crucial for understanding the impact of micronutrient deficiencies on child health.
Purpose of the Study:
- To evaluate the effect of vitamin A supplementation on immune status in preschool children with mild vitamin A deficiency.
- To assess immune competence using the immune response to tetanus immunization as a biomarker.
Main Methods:
- A randomized, double-masked, placebo-controlled trial involving 236 preschool children (ages 3-6) in Indonesia.
- Participants were categorized as clinically normal or having mild xerophthalmia.
- Children received either oral vitamin A (60,000 micrograms retinol equivalent) or placebo, followed by diphtheria-pertussis-tetanus vaccination; immunoglobulin G (IgG) responses to tetanus were measured.
Main Results:
- Children receiving vitamin A supplementation showed a significantly greater immunoglobulin G (IgG) response to tetanus compared to those receiving placebo, irrespective of their initial clinical status.
- This improvement was observed after adjusting for prior tetanus immunization status.
- The findings indicate a relative immune depression in children with mild vitamin A deficiency.
Conclusions:
- Vitamin A supplementation enhances the immune response to tetanus immunization in preschool children.
- Mild vitamin A deficiency is associated with impaired immune function, highlighting the importance of adequate vitamin A status for robust immunity.
- These results support the role of vitamin A supplementation in improving immune competence in vulnerable populations.
Abstract:
A randomized, double-masked, placebo-controlled clinical trial was conducted with 236 preschool children, age 3-6 y, in Indonesia to assess immune status in mild vitamin A deficiency. The immune response to tetanus immunization was used as a measure of immune competence. Clinically normal children (n = 118) and children with mild xerophthalmia (n = 118) were randomly assigned to receive oral vitamin A (60,000 micrograms retinol equivalent) or placebo treatment for a total of four study groups. Two weeks after treatment, children were immunized with diphtheria-pertussis-tetanus vaccine. The immunoglobulin G (IgG) responses to tetanus at baseline and 3 wk following immunization were measured by ELISA. After adjusting for previous tetanus immunization, clinically normal and xerophthalmic children receiving vitamin A had a significantly greater IgG response to tetanus than clinically normal and xerophthalmic children receiving placebo (P less than 0.05). These results suggest that children with mild vitamin A deficiency have a relative immune depression compared with children who have been supplemented to normal vitamin A levels.