Influence of vitamin A status on the antiviral immunity of children with hand, foot and mouth disease.

BACKGROUND & AIMS: Vitamin A (VA) deficiency has been shown to affect antiviral immunity and thus may be related to the progress and outcome of hand, foot and mouth disease (HFMD) in young children. Our objective was to determine whether children with HFMD associated with VA insufficiency displayed a decline in antiviral immunity.

METHODS: 450 children with HFMD and 113 non-infected children were included in this study. Dietary investigations were performed using a 24-h dietary questionnaire. The serum concentrations of VA were measured by high-performance liquid chromatography. The serum levels of interferon-α (IFN-α) and enterovirus 71 (EV71) IgM antibodies were detected using an enzyme-linked immunosorbent assay (ELISA).

RESULTS: The mean serum VA concentration for all patients was 0.73 ± 0.26 μmol/L, and 237 (52.7%) of them presented low concentrations (≤ 0.7 μmol/L). Both serum concentrations of VA and IFN-α in the patients with complications were significantly lower than in patients without complications (P < 0.01). The decreased concentrations of IFN-α and EV71-IgM were positively related to lower VA levels (correlation coefficient = 0.58 and 0.41, respectively, P < 0.001).

CONCLUSIONS: Most of the children with HFMD presented VA insufficiency, which was associated with their reduced immunity and more severe illness.