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Effect of early vitamin A supplementation on cell-mediated immunity in infants younger than 6 mo
M M Rahman1, D Mahalanabis, J O Alvarez
1International Centre for Diarrhoeal Disease Research, Bangladesh.
Insights
Vitamin A supplementation improved cell-mediated immunity (CMI) in infants only when their vitamin A status was adequate. Well-nourished infants showed better CMI responses regardless of vitamin A supplementation.
Area of Science:
- Immunology
- Nutritional Science
- Pediatrics
Background:
- Cell-mediated immunity (CMI) is crucial for infant health.
- Vitamin A status can influence immune responses.
- Diphtheria, pertussis, tetanus/oral polio vaccine (DPT/OPV) immunizations are standard for infants.
Purpose of the Study:
- To investigate the effect of vitamin A supplementation on CMI in infants.
- To determine if vitamin A supplementation impacts immune response to DPT/OPV immunizations.
- To explore the relationship between vitamin A status and CMI response.
Main Methods:
- 120 infants were randomized to receive vitamin A or placebo with DPT/OPV immunizations.
- CMI was assessed using a multitest skin evaluation for tetanus, diphtheria, and tuberculin.
- Serum retinol concentrations were measured to assess vitamin A status.
Main Results:
- Vitamin A supplementation did not significantly alter CMI response overall.
- Adequate serum retinol levels post-supplementation correlated with higher positive CMI tests in the vitamin A group.
- Malnourished infants had lower CMI responses irrespective of supplementation.
Conclusions:
- Vitamin A supplementation enhances CMI in infants with adequate vitamin A status.
- Nutritional status is a key determinant of CMI in young children.
- Targeted vitamin A supplementation may be beneficial for specific infant populations.
Abstract:
One hundred twenty infants were randomly assigned to receive either 15 mg vitamin A or placebo with each of three DPT/OPV (diphtheria, pertussis, tetanus/oral polio vaccine) immunizations at monthly intervals. Sixty-two received vitamin A and 58 received placebo. One month after the third supplementation dose, the response to the delayed cutaneous hypersensitivity test [multitest cell-mediated immunity (CMI) skin evaluation] for tetanus, diphtheria, and tuberculin (purified protein derivative, PPD) was the same in the vitamin A and placebo infants. The number of anergic infants was 17 (27%) and 19 (33%) in the vitamin A and placebo groups, respectively. The number of positive tests among well-nourished infants was significantly higher than that in malnourished infants irrespective of supplementation (P < 0.001). Among the infants with adequate serum retinol concentrations (> 0.7 mumol/L) after supplementation, the vitamin A-supplemented infants had a significantly higher proportion of positive CMI tests than the placebo infants (chi-square test: 8.99, P = 0.008). Among the infants with low serum retinol concentrations (< 0.7 mumol/L) after supplementation, vitamin A supplementation had no effect on CMI response. These results indicate that CMI in young infants was positively affected by vitamin A supplementation only in those infants whose vitamin A status was adequate (ie, serum retinol > 0.7 mumol/L) at the time of the CMI test. CMI was consistently better in well-nourished infants irrespective of supplementation.