Abstract:
Intestinal helminth infection is associated with altered immune responses and micronutrient
status in infected children. These alterations compromise vaccine efficacy of infected
children. There is paucity of information on the interplay between humoral immunity,
nutritional status and vaccine response, before and after anthelminthic (Albendazole)
treatment or oral vaccination in Ascaris lumbricoides (Al)–infected Nigerian children. This
study was designed to assess the micronutrient status and immune responses to vaccines in
Al–infected Nigerian children before and after anthelminthic treatment or oral vaccination.
After ethical approval (UI/EC/13/0331) and informed consent were obtained, a total of 349
children [149 preschool-aged (PSAC) and 200 school-aged children (SAC)] were enrolled
into this case-control study. The stool samples were collected and examined for helminth ova
using the concentration technique. Twenty three of the Al–infected children were
Albendazole treated (AT) while twenty three received oral poliovirus vaccine (OPV) and
nineteen received oral rotavirus vaccine (ORV). Age and sex-matched helminth free children
were randomly selected as controls. Sera were collected before, one and two months after
Albendazole treatment or three weeks after oral vaccinations. Serum concentrations of zinc
and selenium were determined using Atomic Absorption Spectrophotometry. Vitamins A and
C concentrations were determined using HPLC. Interferon–γ (IFN–γ), tumour necrosis
factor–α, interleukins (IL)-4, 6, 8 and 10, transferrin, poliovirus-specific IgA and rotavirus specific IgA concentrations were determined using ELISA. Data were expressed as
mean±SEM and analysed using Mann-Whitney U test, Wilcoxon Signed Ranks Test and
Kruskal Wallis Test, with levels of significance set at α0.05.
Eighty three (23.7%) of the children were infected with A. lumbricoides. In SAC, serum zinc
(139.1±2.5 vs 152.7±2.4µg/dL) and vitamin A (119.3±1.7 vs 153.6±5.5µg/dL) levels were
significantly lower while transferrin (178.9±4.1 vs 137.9±4.2mg/dL), selenium (62.1±5.8 vs
35.5±1.6ng/mL), IL-8 (995.2±49.3 vs 562.9±44.0pg/mL), IL-6 (16.6±1.8 vs 4.9±0.4pg/mL),
IFN–γ (105.9±9.2 vs 62.9±11.6pg/mL), and IL-4 (210±18.3 vs 106.6±2.5pg/mL) levels were
significantly higher in Al-infected group compared with controls. In AT group, serum vitamin
A levels were significantly higher at one month (203.6±5.4 vs 118.5±2.0µg/dL) and two
months (206.2±5.0 vs 118.5±2.0µg/dL) while IL-8 was significantly lower at one month
(433.7±85.9vs 619.4±77.4pg/mL) compared with pre-treatment values. In OPV-vaccinated
group, post-vaccination serum IL-8 (703.1±41.5 vs 1063.2±69.7pg/mL) and IL-6 (8.1±0.7 vs
7
14.7±2.5pg/mL) levels were significantly lower compared with pre-vaccination levels. Also,
post-vaccination serum poliovirus-specific IgA level was lower in OPV-vaccinated group and
higher in controls compared with pre-vaccination levels, but not significant. In ORV vaccinated group, post-vaccination serum IFN–γ (101.6±18.4 vs 181.1±37.3pg/mL), IL-4
(230.4±55.8 vs 507.1±130.2pg/mL), and IL-8 (545.3±78.9 vs 966.8±159.6pg/mL) levels
were significantly lower while IL-10 (0.25±0.04 vs 0.13±0.02ng/mL) level was significantly
higher compared with pre-vaccination levels. Also, serum rotavirus-specific IgA level was
not significantly lower in ORV-vaccinated group, but was significantly higher (7.9±0.7 vs
6.9±0.4mg/dL) in controls compared with pre-vaccination levels.
Inflammation, deficiencies of zinc, vitamin A and reduced vaccine-specific immunoglobulin
A are associated with Ascaris lumbricoides infection in Nigerian children but were reversed
with anthelminthic treatment. Anthelminthic treatment with micronutrient supplementation
will benefit children during vaccination.
