Quantity and Quality of Naturally Acquired Antibody Immunity to the Pneumococcal Proteome Throughout Life.

BACKGROUND: Young children and older adults are susceptible for invasive pneumococcal disease (IPD) caused by Streptococcus pneumoniae. Pneumococcal protein-specific antibodies play a protective role against IPD; however, not much is known about the pace of acquisition, maturation, and maintenance of these antibodies throughout life. METHODS: Immunoglobulin G (IgG) and IgA levels, avidity, and/or specificity to the pneumococcal proteome in serum and saliva from healthy young children, adults, and older adults, with known carriage status, were measured by enzyme-linked immunosorbent assay (ELISA) and 2-dimensional western blotting against ΔcpsTIGR4. RESULTS: Eleven-month-old children, the youngest age group tested, had the lowest pneumococcal proteome-specific IgG and IgA levels and avidity in serum and saliva, followed by 24-month-old children and were further elevated in adult groups. Among adult groups, the parents had the highest serum and saliva IgG and IgA antibody levels. In children, antibody levels and avidity correlated with daycare attendance and presence of siblings, posing as proxy for exposure and immunization. Immunodominance patterns slightly varied throughout life. CONCLUSIONS: Humoral immunity against the pneumococcal proteome is acquired through multiple episodes of pneumococcal exposure. Low-level and low-avidity antiproteome antibody profiles in young children may contribute to their IPD susceptibility, while in overall antiproteome antibody-proficient older adults other factors likely play a role.

Effect of a dietary intervention including minimal and unprocessed foods, high in natural saturated fats, on the lipid profile of children, pooled evidence from randomized controlled trials and a cohort study.

AIM: To study the possible effects of a dietary intervention with minimal and unprocessed foods, high in natural saturated fats on the lipid profile and body mass index of children. METHOD: This study combines three intervention studies; one non-randomized retrospective cohort study and two randomized controlled trials, to a pooled analysis. The intervention group received a dietary intervention of minimal and unprocessed foods for three to six months, consisting of five times per week green vegetables, three times per week beef, daily 200-300 mL whole cow's milk (3.4% fat) and whole dairy butter (80% fat) on each slice of bread. The control group continued their usual dietary habits. Raw data of the three intervention studies where combined into one single dataset for data analysis, using mixed effects analysis of covariance to test the effects of the dietary advice on the main study outcomes, which are measurements of the lipid profile. RESULTS: In total, 267 children aged 1 to 16 years were followed. 135 children were included in the intervention group and 139 children in the control group. Characteristics (age, gender and follow-up period) were equally distributed between the groups at baseline. In the intervention group HDL-cholesterol increased significantly from 1.22 mmol/L, 95% confidence interval (CI) 1.14-1.32 to 1.42 mmol/L 95% CI 1.30-1.65 (p = 0.007). The increase over time in HDL cholesterol in the intervention group was significantly different compared to the increase in the control group (from 1.26 mmol/L, 95% CI 1.19-1.35, to 1.30 mmol/L, 95% CI 1.26-1.37) (p = 0.04). Due to the increased HDL concentration in the intervention group, the total cholesterol/HDL cholesterol ratio decreased significantly from 3.70 mmol/L, 95% CI 3.38-3.87, to 3.25 mmol/L, 95% CI 2.96-3.31 (p = 0.05). CONCLUSION: Consumption of minimal and unprocessed foods (high in natural saturated fats) has favourable effects on HDL cholesterol in children. Therefore, this dietary advice can safely be recommended to children.