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Vitamin A levels and immunity in humans
Janine Jason1, Lennox K Archibald, Okey C Nwanyanwu
1HIV Immunology and Diagnostics Branch, Division of AIDS, STD, and TB Laboratory Research, National Center for Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia 30333, USA. JMJ1@cdc.gov
Clinical and Diagnostic Laboratory Immunology
|May 3, 2002
Summary
Vitamin A deficiency in African children is linked to a stronger type 1 immune response, potentially benefiting those with HIV or tuberculosis. This study highlights the immune system
Area of Science:
- Immunology
- Nutritional Science
- Public Health
Background:
- Vitamin A deficiency is prevalent in Africa, alongside high rates of HIV and Mycobacterium tuberculosis infections.
- Control of these infections relies on type 1 cytokine (cellular) immunity.
- Animal studies show vitamin A deficiency shifts immunity towards type 1 cytokines, but human data are lacking.
Purpose of the Study:
- To investigate the relationship between serum vitamin A levels and immune parameters in hospitalized children in Malawi.
- To explore associations with HIV status, BCG vaccine response, and clinical findings.
Main Methods:
- Serum vitamin A levels were measured in 70 hospitalized children.
- Cell-specific cytokine production was assessed using flow cytometry.
- Immune status, HIV infection, BCG scarring, and clinical symptoms were analyzed using nonparametric statistics and logistic regression.
Main Results:
- 30% of children had severe vitamin A deficiency (<10 microg/dl), 34% moderate (10 to <20 microg/dl).
- Lower vitamin A levels correlated with higher proportions of natural killer (NK) cells and a shift towards type 1 cytokine profiles.
- Vitamin A-deficient children showed increased respiratory symptoms and BCG scar prevalence, indicating a type 1 immune response.
Conclusions:
- Lower vitamin A levels in children are associated with a relative type 1 cytokine dominance and increased NK cells.
- This immune profile may offer some protection against type 1 pathogens like HIV and Mycobacterium tuberculosis.
- Findings underscore the complex interplay between nutrition and cellular immunity in vulnerable populations.