Schistosomiasis Coinfection in Children Influences Acquired Immune Response against Plasmodium falciparum Malaria Antigens

Background: Malaria and schistosomiasis coinfection frequently occurs in tropical countries. This study evaluates the influence of Schistosoma haematobium infection on specific antibody responses and cytokine production to recombinant merozoite surface protein-1-19 (MSP1-19) and schizont extract of Plasmodium falciparum in malaria-infected children. Methodology: Specific IgG1 to MSP1- 19, as well as IgG1 and IgG3 to schizont extract were significantly increased in coinfected children compared to P. falciparum mono-infected children. Stimulation with MSP1- 19 lead to a specific production of both interleukin-10 (IL-10) and interferon-c (IFN-c), whereas the stimulation with schizont extract produced an IL-10 response only in the coinfected group. Conclusions: Our study suggests that schistosomiasis coinfection favours anti-malarial protective antibody responses, which could be associated with the regulation of IL-10 and IFN-c production and seems to be antigen-dependent. This study demonstrates the importance of infectious status of the population in the evaluation of acquired immunity against malari

Compatibility of stabilized whole blood products with CD4 technologies and their suitability for quality assessment programs.

BACKGROUND: CD4 T cell enumeration is the most widely used prognostic marker for management of HIV disease. Internal quality control and external quality assessment (EQA) programs are critical to ensure reliability of clinical measurements. The utility of stabilized whole blood products (SWBP) as a test reagent for EQA programs such as Quality Assessment and Standardization for Immunological measures relevant to HIV/AIDS (QASI) program have been demonstrated previously. Since then, several new commercial SWBPs and alternative CD4 enumeration technologies have become available. Seven SWBPs were evaluated on seven different enumeration platforms to determine which product(s) are most suitable for EQA programs that support multiple analytical technologies. METHOD: Assessment of SWBPs was based on two criteria: (1) accuracy of CD4 T cell measurements and; (2) stability under sub optimal storage conditions. RESULTS: Three SWBPs (Multi-Check, StatusFlow and CD4 Count) showed accurate CD4 T-cell absolute count and percentage values across six of the enumeration platforms. All products retain stability up to 18 days at 21-23°C with the exception of Multi-Check-high on FacsCount and Multi-Check-Low and StatusFlow-Low on Pima. One of the products (CD4 Count) retained stability for three days on all platforms tested when stored at 37°C. CONCLUSION: This study demonstrated that the characteristics of commercially available SWBPs vary across multiple CD4 platforms. The compatibility of testing panels for EQA programs with multiple analytical platforms needs to be carefully considered, especially in large multiplatform CD4 EQA programs. The selection of a suitable cross-platform SWBP is an increasing challenge as more reagents and platforms are introduced for CD4 T-cell enumeration

Stability of <i>Multi-Check</i>, <i>StatusFlow</i> and <i>CD4 Count</i> stabilized whole blood products (SWBPs) under different conditions on various platforms.

<p>Stability of <i>Multi-Check</i>, <i>StatusFlow</i> and <i>CD4 Count</i> stabilized whole blood products (SWBPs) under different conditions on various platforms.</p

Mean ± Standard Deviation of CD4 T-cell percentage measurements for each stabilized whole blood product on the different enumeration platforms.

<p>* = multiple lots combined.</p><p>NM = not measurable.</p

FacsCalibur Multiset analysis of stabilized whole blood products (SWBPs).

<p>Low CD4 level SWBP and fresh whole blood stained with CD4FITC/CD8PE/CD3PerCP antibody combination are shown. Two dot plots are shown for each analysis: CD3×CD4 with attractor gate on CD3+4− cells cluster; CD4×CD8 (upper right corner) with attractor gate on beads, CD4, CD8 and double positive CD4+8+ cells cluster.</p

List of stabilized whole blood products tested.

<p>*Obtained by the reference method.</p

Analysis of Low CD4 level SWBPs on CyFlow.

<p>Stabilized whole blood products (low CD4 level) and fresh whole blood stained with CD4% easy count on CyFlow Counter are shown. Each CD4×SSC dot plot displays two gates: (1) “CD4” gate set around CD4 lymphocytes cluster and (2) “LYM” gate set around all lymphocytes.</p

FacsCalibur Multiset analysis of different SWBPs.

<p><i>Multi-Check</i>, <i>StatusFlow</i> and <i>CD4 Count</i> (low CD4 level) were prepared with MultiTest reagent CD3FITC/CD8PE/CD45PerCP/CD4APC on product incubated for 1 (D1) and 2 (D2) days at 37°C. Analysis displayed CD45×SSC dot plots with automated CD45 gates.</p

Residual values obtained for each stabilized whole blood product (SWBP) from CD4 percentages measurements.

<p>Technologies “a–j” are detailed in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0103391#pone-0103391-t002" target="_blank">table 2</a>.</p><p>Italic values = values out of range.</p><p>NM = not measurable.</p><p>Score = number of values within the range.</p

Guava PCA analysis of of different SWBPS.

<p><i>Multi-Check</i>, <i>StatusFlow</i> and <i>CD4 Count</i> (low CD4 level) were prepared using the CD3/CD4 reagent kit on product stored at 4°C (D0) and products stored for 1 day at 37°C (D1). Analysis required first setting cursors around the CD3 cells population FSC×CD3 PECy5 dot plot and then isolating the CD4 positive cells cluster on CD4PE×CD3PECy5.</p