Serum anti-flagellin and anti-lipopolysaccharide immunoglobulins as predictors of linear growth faltering in Pakistani infants at risk for environmental enteric dysfunction

Background: Environmental Enteric Dysfunction (EED) in children from low-income countries has been linked to linear growth declines. There is a critical need to identify sensitive and early EED biomarkers.Objective: Determine whether levels of antibodies against bacterial components flagellin (flic) and lipopolysaccharide (LPS) predict poor growth.Design/Methods: In a prospective birth cohort of 380 children in rural Pakistan blood and stool samples were obtained at ages 6 and 9 months. Linear mixed effects models were used to examine longitudinal associations between quartiles of anti-flic and anti-LPS antibodies and changes in LAZ, WAZ and WLZ scores. Spearman\u27s correlations were measured between anti-flic and anti-LPS immunoglobulins with measures of systemic/enteric inflammation and intestinal regeneration.Results: Anti-LPS IgA correlated significantly with CRP, AGP and Reg1 serum at 6mo and with MPO at 9mo. In multivariate analysis at 6mo of age, higher anti-LPS IgA levels predicted greater declines in LAZ scores over subsequent 18mo (comparing highest to lowest quartile, β (SE) change in LAZ score/year = -0.313 (0.125), p-value = 0.013). Anti-flic Ig A in the two highest quartiles measured at 9mo of age had declines in LAZ of -0.269 (0.126), p = 0.033; and -0.306 (0.129), p = 0.018 respectively, during the subsequent 18mo of life, compared to those in the lowest quartile of anti-flic IgA.Conclusions and Relevance: Elevated anti-flic IgA and anti-LPS IgA antibodies at 6 and 9mo, predict declines in linear growth. Systemic and enteric inflammation correlated with anti-LPS IgA provides mechanistic considerations for potential future interventions

Cumulative age distribution of children less than 5 years of age admitted with severe diarrhea at five sentinel hospitals in Pakistan, 2006–2008.

<p>Bars represent number of children with rotavirus- positive diarrhea. Points represent cumulative rate (%) of rotavirus- positive gastroenteritis.</p

Geographic distribution of the five sentinel sites participating in rotavirus surveillance in Pakistan from 2006–2008.

<p>Geographic distribution of the five sentinel sites participating in rotavirus surveillance in Pakistan from 2006–2008.</p

Distribution of rotavirus positive gastroenteritis by age in months at five sentinel hospitals in Pakistan from 2006–2008.

<p>Distribution of rotavirus positive gastroenteritis by age in months at five sentinel hospitals in Pakistan from 2006–2008.</p

Distribution of genotype of rotavirus strains determined in children less than 5 years of age admitted with acute gastroenteritis in Pakistan, 2006–2008.

<p>Distribution of genotype of rotavirus strains determined in children less than 5 years of age admitted with acute gastroenteritis in Pakistan, 2006–2008.</p

Infant and Maternal Characteristics at six and nine months^*.

<p>Infant and Maternal Characteristics at six and nine months^{<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0193768#t001fn002" target="_blank">*</a>}.</p

The association of anti-flagellin and anti-lipopolysaccharide immunoglobulin concentrations at 6 and 9 months with annual Z score changes for length using linear mixed effects models.

<p>The association of anti-flagellin and anti-lipopolysaccharide immunoglobulin concentrations at 6 and 9 months with annual Z score changes for length using linear mixed effects models.</p

Median LAZ, WLZ and WAZ scores in Pakistani infants over 18 months of follow-up.

<p>Dashed lines show q1 and q3 quartiles. Abbreviations: LAZ = Length-for-Age Z score, WLZ = Weight-for-Length Z score and WAZ = Weight-for-Age Z score.</p

Anti-Flagellin and anti-LPS immunoglobulin concentrations in Pakistani infants.

<p>Closed shapes indicate means±SDs in Pakistani infants over the follow-up period. Open shapes indicate means±SDs values in 36 healthy Boston infants with a mean age of 9.5 months. n = 380 for all immunoglobulins in Pakistani infants at 6 and 9 months of age; n = 36 for all immunoglobulins in Boston infants at 9.5 months of age. **** p< 0.0001, ** p< 0.01 and * p< 0.05 for comparisons of mean biomarker concentrations in Pakistani infants with those of healthy Boston infants (unpaired t tests).</p

Correlation coefficient matrix of immunoglobulins to flagellin and lipolysaccharide with measures of systemic inflammation and enteric inflammation & regeneration.

<p>Correlation coefficient matrix of immunoglobulins to flagellin and lipolysaccharide with measures of systemic inflammation and enteric inflammation & regeneration.</p