HUMORAL IMMUNE RESPONSES AND MICRONUTRIENT LEVELS OF Ascaris lumbricoides-INFECTED NIGERIAN CHILDREN ON ANTHELMINTHIC DRUG OR ORAL VACCINATIONS

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.