Underweight Full-Term Indian Neonates Show Differences in Umbilical Cord Blood Leukocyte Phenotype: A Cross-Sectional Study

<div><p>Background</p><p>While infections are a major cause of neonatal mortality in India even in full-term neonates, this is an especial problem in the large proportion (~20%) of neonates born underweight (or small-for-gestational-age; SGA). One potential contributory factor for this susceptibility is the possibility that immune system maturation may be affected along with intrauterine growth retardation.</p><p>Methods</p><p>In order to examine the possibility that differences in immune status may underlie the susceptibility of SGA neonates to infections, we enumerated the frequencies and concentrations of 22 leukocyte subset populations as well as IgM and IgA levels in umbilical cord blood from full-term SGA neonates and compared them with values from normal-weight (or appropriate-for-gestational-age; AGA) full-term neonates. We eliminated most SGA-associated risk factors in the exclusion criteria so as to ensure that AGA-SGA differences, if any, would be more likely to be associated with the underweight status itself.</p><p>Results</p><p>An analysis of 502 such samples, including 50 from SGA neonates, showed that SGA neonates have significantly fewer plasmacytoid dendritic cells (pDCs), a higher myeloid DC (mDC) to pDC ratio, more natural killer (NK) cells, and higher IgM levels in cord blood in comparison with AGA neonates. Other differences were also observed such as tendencies to lower CD4:CD8 ratios and greater prominence of inflammatory monocytes, mDCs and neutrophils, but while some of them had substantial differences, they did not quite reach the standard level of statistical significance.</p><p>Conclusions</p><p>These differences in cellular lineages of the immune system possibly reflect stress responses in utero associated with growth restriction. Increased susceptibility to infections may thus be linked to complex immune system dysregulation rather than simply retarded immune system maturation.</p></div

Additional file 4: of Hypothermia for encephalopathy in low and middle-income countries (HELIX): study protocol for a randomised controlled trial

SPIRIT checklist. (PDF 77 kb

Characteristics of participant population.

<p>^<i>a</i> All values are Mean (SD) except where specified</p><p>^<i>b</i> To convert zinc in μg/dL to SI unit (μmol/L) multiply by 0.153</p><p>SGA, small for gestational age (birth weight below the 10th centile or 2SD below mean for GA of reference/normal birth curves); AGA, appropriate for gestational age (birth weight between the 10^th and 90^th centile for GA of reference/normal birth curves).</p><p>Characteristics of participant population.</p

Comparison of relative frequencies of immune markers between term SGA and AGA newborns.

<p>^<i>a</i> All immune marker variables have been log transformed</p><p>^{<b><i>b</i></b>} Adjusted for pre-specified factors: maternal age & newborn gender</p><p>SGA, small for gestational age (birth weight below the 10^th centile or 2SD below mean for GA of reference/normal birth curves); AGA, appropriate for gestational age (birth weight between the 10^th and 90^th centile for GA of reference/normal birth curves); ERC, exponentiated regression coefficient, ordinary least square (OLS) regression analysis after log transformation of dependent variable (immune marker); 95% CI, 95 percent confidence interval.</p><p>Comparison of relative frequencies of immune markers between term SGA and AGA newborns.</p

NK cells, but not innate-like T cells, show significant difference between AGA and SGA cord blood.

<p>(A) Comparison of proportions and absolute concentrations of NKT, iNKT and TCRγ/δ cells (median, IQR and 95% CI) along with p values. (B) Comparison of proportions and absolute numbers of immature NK cells (median, IQR and 95% CI) along with p values.</p

Comparison of absolute concentrations of immune markers between term SGA and AGA newborns.

<p>^<i>a</i> All immune marker (IM) variables have been log transformed</p><p>^{<b><i>b</i></b>} Adjusted for pre-specified factors: maternal age & newborn gender</p><p>^<i>c</i> To convert IgM in mg/dL to SI unit (mg/L) multiply by 10</p><p>SGA, small for gestational age (birth weight below the 10^th centile or 2SD below mean for GA of reference/normal birth curves); AGA, appropriate for gestational age (birth weight between the 10^th and 90^th centile for GA of reference/normal birth curves); ERC, exponentiated regression coefficient, ordinary least square (OLS) regression analysis after log transformation of dependent variable (immune marker); 95% CI, 95 percent confidence interval.</p><p>Comparison of absolute concentrations of immune markers between term SGA and AGA newborns.</p

Neutrophils and NK cells are more prominent in SGA cord blood.

<p>(A) Absolute numbers of leukocytes in cord blood from AGA and SGA babies (median, interquartile range [IQR] and 95% confidence interval (CI). Adjusted p values (as mentioned in Tables <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0123589#pone.0123589.t002" target="_blank">2</a>–<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0123589#pone.0123589.t003" target="_blank">3</a>; Tables B-C in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0123589#pone.0123589.s001" target="_blank">S1 File</a>) shown for each panel. (B) Major lineages in cord blood as % of total leukocytes (median, IQR and 95% CI) along with p values. (C) Absolute concentrations of major cell lineages in cord blood (median, IQR and 95% CI) along with p values.</p

Classical monocytes, myeloid and plasmacytoid DCs as well as mDC: pDC ratios differ between AGA and SGA cord blood.

<p>(A) Comparison of proportions of monocyte subsets and absolute concentrations (median, IQR and 95% CI) along with p values. (B) Comparison of proportions of DC subsets and absolute concentrations (median, IQR and 95% CI) along with p values. (C) Comparison of mDC: pDC ratios in cord blood (median, IQR and 95% CI) along with p value. (D) Comparison of concentrations of zinc in cord blood (median, IQR and 95% CI) along with p value.</p

Immature naïve B cells, IgM levels and CD4:CD8 ratios show differences between AGA and SGA cord blood.

<p>(A) Comparison of proportions of B cell subsets and absolute concentrations (median, IQR and 95% CI) along with p values. (B) Comparison of absolute concentrations of IgM and IgA in cord blood (median, IQR and 95% CI) along with p values. (C) Comparison of proportions of T cell subsets (median, IQR and 95% CI) along with p values. (D) Comparison of absolute numbers of T cell subsets (median, IQR and 95% CI) along with p values. (E) Comparison of CD4:CD8 ratios (median, IQR and 95% CI) along with p value.</p