Sources of heterogeneity in human monocyte subsets

AbstractHuman monocytes are commonly defined and discriminated by the extent of their cell surface expression of CD14 and CD16, with associated differences in function and phenotype related to the intensity of expression of these markers. With increasing interest into the function and behaviour of monocytes, it is important to have a clear understanding of how differing strategies of analysis can affect results and how different protocols and population backgrounds can affect this highly morphogenic cell type.Using PBMCs from populations with differing ethnicities and histories of parasite exposure we have characterized monocyte phenotype based on intensity of CD14 and CD16 expression. Using the surface markers HLA-DR, CCR2 and CX3CR1, we compared monocyte phenotype between populations and further assessed changes in monocytes with freezing and thawing of PBMCs.Our results reveal that there is a progression of surface marker expression based on intensity of CD14 or CD16 expression, stressing the importance of careful gating of monocyte subtypes. Freezing and thawing of the PBMCs has no effect generally on the monocytes, although it does lead to a decrease in CD16 and CX3CR1 expression. We show that there are differences in the monocyte populations based on ethnicity and history of exposure to the common parasites Plasmodium falciparum and Schistosoma haematobium.This study highlights that blood monocytes consist of a continuous population of cells, within which the dominant phenotype may vary dependent on the background of the study population. Comparing results from monocyte studies therefore needs to be done with great care, as ethnic background of donor population, gating strategy and processing of PBMCs may all have an effect on outcome of monocyte phenotype

Chitinase 3-Like 1 Protein Levels Are Elevated in Schistosoma haematobium Infected Children

Currently there are few studies characterising the nature and aetiology of human schistosome-related inflammatory processes. The aim of this study was to determine the relationship between Chitinase 3-like 1 (CHI3L1), also known as YKL-40, a molecule associated with inflammatory processes, and schistosome infection, morbidity and systemic cytokine levels. Methods Serological levels of CHI3L1 and a panel of cytokines (IFN-y, IL-4/5/6/9/10/13 and 17) were measured in two Zimbabwean populations resident in a high and low schistosome infection area. CHI3L1 levels were related to schistosome infection, haematuria status and cytokine levels after allowing for confounding variables. The effect of antihelminthic treatment with praziquantel on CHI3L1 levels was determined in 246 participants 6 weeks post-treatment. Results CHI3L1 levels increased with age in both areas but were significantly higher in the high infection areas compared to the low infection area. CHI3L1 levels were also higher in infected compared to uninfected individuals with this difference being significant in the youngest age group. Curative antihelminthic treatment resulted in a significant decrease in CHI3L1 levels. Of the cytokines, only IL-10 and IL-17 had a significant association with CHI3L1 levels, and this association was negative. Conclusions Serum CHI3L1 levels differ between infected and uninfected people before and after antihelminthic treatment. The greatest difference occurs in the youngest age group, in keeping with the period when schistosome-related pathological processes are initiated. Following from previous studies in non-infectious diseases showing that CHI3L1 is a biomarker for the inflammatory process, this study suggests that the potential for CHI3L1 as a biomarker for schistosome-related pathology should be explored further.World Health Organisation (www.who.org); the Wellcome Trust (http://www.wellcome.ac.uk/) [grant number WT082028MA]; the Thrasher Foundation (http://www.thrasherresearch.org/) to [FM]; and by the Medical Research Council (http://www.mrc.ac.uk) [grant number G0600818 to JEA, PhD studentship LJA-544 to LJA]

Independent and combined effects of improved water, sanitation, and hygiene, and improved complementary feeding, on child stunting and anaemia in rural Zimbabwe: a cluster-randomised trial.

BACKGROUND: Child stunting reduces survival and impairs neurodevelopment. We tested the independent and combined effects of improved water, sanitation, and hygiene (WASH), and improved infant and young child feeding (IYCF) on stunting and anaemia in in Zimbabwe. METHODS: We did a cluster-randomised, community-based, 2 × 2 factorial trial in two rural districts in Zimbabwe. Clusters were defined as the catchment area of between one and four village health workers employed by the Zimbabwe Ministry of Health and Child Care. Women were eligible for inclusion if they permanently lived in clusters and were confirmed pregnant. Clusters were randomly assigned (1:1:1:1) to standard of care (52 clusters), IYCF (20 g of a small-quantity lipid-based nutrient supplement per day from age 6 to 18 months plus complementary feeding counselling; 53 clusters), WASH (construction of a ventilated improved pit latrine, provision of two handwashing stations, liquid soap, chlorine, and play space plus hygiene counselling; 53 clusters), or IYCF plus WASH (53 clusters). A constrained randomisation technique was used to achieve balance across the groups for 14 variables related to geography, demography, water access, and community-level sanitation coverage. Masking of participants and fieldworkers was not possible. The primary outcomes were infant length-for-age Z score and haemoglobin concentrations at 18 months of age among children born to mothers who were HIV negative during pregnancy. These outcomes were analysed in the intention-to-treat population. We estimated the effects of the interventions by comparing the two IYCF groups with the two non-IYCF groups and the two WASH groups with the two non-WASH groups, except for outcomes that had an important statistical interaction between the interventions. This trial is registered with ClinicalTrials.gov, number NCT01824940. FINDINGS: Between Nov 22, 2012, and March 27, 2015, 5280 pregnant women were enrolled from 211 clusters. 3686 children born to HIV-negative mothers were assessed at age 18 months (884 in the standard of care group from 52 clusters, 893 in the IYCF group from 53 clusters, 918 in the WASH group from 53 clusters, and 991 in the IYCF plus WASH group from 51 clusters). In the IYCF intervention groups, the mean length-for-age Z score was 0·16 (95% CI 0·08-0·23) higher and the mean haemoglobin concentration was 2·03 g/L (1·28-2·79) higher than those in the non-IYCF intervention groups. The IYCF intervention reduced the number of stunted children from 620 (35%) of 1792 to 514 (27%) of 1879, and the number of children with anaemia from 245 (13·9%) of 1759 to 193 (10·5%) of 1845. The WASH intervention had no effect on either primary outcome. Neither intervention reduced the prevalence of diarrhoea at 12 or 18 months. No trial-related serious adverse events, and only three trial-related adverse events, were reported. INTERPRETATION: Household-level elementary WASH interventions implemented in rural areas in low-income countries are unlikely to reduce stunting or anaemia and might not reduce diarrhoea. Implementation of these WASH interventions in combination with IYCF interventions is unlikely to reduce stunting or anaemia more than implementation of IYCF alone. FUNDING: Bill & Melinda Gates Foundation, UK Department for International Development, Wellcome Trust, Swiss Development Cooperation, UNICEF, and US National Institutes of Health.The SHINE trial is funded by the Bill & Melinda Gates Foundation (OPP1021542 and OPP113707); UK Department for International Development; Wellcome Trust, UK (093768/Z/10/Z, 108065/Z/15/Z and 203905/Z/16/Z); Swiss Agency for Development and Cooperation; US National Institutes of Health (2R01HD060338-06); and UNICEF (PCA-2017-0002)

Description of study population.

<p>Note. Infection Range (eggs/10 ml urine) and sample sizes, according to age group. Abbreviations: N, sample size; M, male; F, female.</p

CHI3L1 levels in haematuria positive and haematuria negative individuals.

<p>CHI3L1 levels according to haematuria status. P values are obtained from t-test on age, sex and infection status matched individuals.</p

F and P values of the factors affecting levels of chitinase 3-like 1 in serum.

<p>Note. F and P values from analysis of variance (total degrees of freedom (df) = 858). Sex: Male or Female; Residential areas: high infection area and low infection area; Age groups as described in <a href="http://www.plosntds.org/article/info:doi/10.1371/journal.pntd.0001898#pntd-0001898-t001" target="_blank">Table 1</a>; Infection status: egg positive or egg negative.</p>**<p>Indicates significant p values.</p

Effect of treatment on CHI3L1 protein levels.

<p>Mean CHI3L1 expression within an untreated (n = 136) and a treated population (n = 110) by age group. Week 0 (open), 6 weeks later (solid), bars represent standard error of the mean. Significant p-values from posthoc ANOVA are indicated in bold.</p

Relationship between CHI3L1 protein and infection status in different age groups.

<p>Figure shows mean levels of CHI3L1 protein (log₁₀(x+1)). Uninfected individuals (open) compared to infected (solid). Bars represent standard error of the mean. P-values are obtained from posthoc tests after taking into account residential area. Significant p-values are indicated in bold.</p

Age profiles for infection intensity and CHI3L1 serum protein levels.

<p>Age profiles for the study areas, shown as circles for the high infection area and squares for the low infection areas. Bars represent standard error of the mean. A. Infection intensity exhibiting a peak shift between the two villages. B. Chitinase 3-like 1 protein showing no peak shift between the two villages.</p