Increased CD4⁺CRTH2⁺ Th2 cell frequencies in peripheral blood of <i>M</i>. <i>perstans</i> microfilaremic individuals.

<p>Using flow cytometry, peripheral whole blood cells from <i>M</i>. <i>perstans</i> microfilaremic (Mp MF+; n = 11) and amicrofilaremic (Mp MF-; n = 10) individuals were analyzed for frequencies (%) of (<b>A</b>) CD4⁺ T cells on lymphocytes and CD4⁺ T cells expressing (<b>B</b>) CXCR3, (<b>C</b>) CD161, (<b>D</b>) CRTH2, (<b>E</b>) CTLA-4 or (<b>F</b>) PD-1. Graphs show box whiskers with median, interquartile ranges and outliers. Statistical significances between the indicated groups were obtained using the Mann-Whitney-U-test.</p

Increased frequencies of regulatory T and B cells (Tregs and Bregs) but decreased type 1 regulatory T (Tr1) cell populations in <i>M</i>. <i>perstans</i> microfilaremic individuals.

<p>Using flow cytometry, peripheral whole blood cells from <i>M</i>. <i>perstans</i> microfilaremic (Mp MF+; n = 11) and amicrofilaremic (Mp MF-; n = 10) individuals were analyzed for frequencies (%) of (<b>A</b>) CD4⁺CD127⁺ expressing CD25^high Tregs, (<b>B</b>) CD4+α/βTCR⁺ expressing CD49b and LAG3 Tr1 cells and (<b>C</b>) CD19⁺CD24^highCD38^high expressing CD1d^high Bregs. Graphs show box whiskers with median, interquartile ranges and outliers. Statistical significances between the indicated groups were obtained using the Mann-Whitney-U-test.</p

Reduced systemic IL-13, IL-4 and IL-17A levels in <i>M</i>. <i>perstans</i> microfilaremic individuals.

<p>Sera from <i>M</i>. <i>perstans</i>-microfilaremic (Mp MF+, n = 11) and amicrofilaremic (Mp MF-; n = 28) individuals were analyzed for the contents of (<b>A</b>) IFN-γ, (<b>B</b>) IL-5, (<b>C</b>) IL-13, (<b>D</b>) IL-4, (<b>E</b>) IL-10 and (<b>F</b>) IL-17A using luminex technology. Graphs show box whiskers with median, interquartile ranges and outliers. Statistical significances between the indicated groups were obtained using the Mann-Whitney-U-tests.</p

Elevated frequencies of CD3^-CD16⁺CD56⁺ natural killer cells in peripheral blood of <i>M</i>. <i>perstans</i>-microfilaremic individuals.

<p>Using flow cytometry, peripheral whole blood cells from <i>M</i>. <i>perstans</i> microfilaremic (Mp MF+; n = 11) and amicrofilaremic (Mp MF-; n = 10) individuals were analyzed for frequencies (%) of (<b>A</b>) CD3⁺ T cells co-expressing CD16 and CD56 for NKT cells and (<b>B</b>) CD3^- cells co-expressing CD16 and CD56 to determine NK populations. Graphs show box whiskers with median, interquartile ranges and outliers. Statistical significances between the indicated groups were obtained using the Mann-Whitney-U-test.</p

<i>Mansonella perstans</i> microfilaremic individuals are characterized by enhanced type 2 helper T and regulatory T and B cell subsets and dampened systemic innate and adaptive immune responses

<div><p>The filarial nematode <i>Mansonella perstans</i> is endemic throughout Africa, northern South America and the Caribbean. Interestingly, <i>M</i>. <i>perstans</i>-infected individuals present no distinct clinical picture associated with certain pathology. Due to its relatively silent nature, research on this tropical disease has been neglected, especially <i>M</i>. <i>perstans</i>-driven immune responses. A hindrance in obtaining data on <i>M</i>. <i>perstans</i>-specific responses has been the inability to obtain adult worms since their habitats in serous cavities are difficult to access. Thus, in this study, for the first time, we used <i>Mansonella perstans</i> worm antigen extract as stimulant to obtain filarial-specific recall and immunoglobulin responses from <i>M</i>. <i>perstans</i> microfilaremic individuals (Mp MF+) from Cameroon. Moreover, systemic immune profiles in sera and immune cell composition in peripheral blood from Mp MF+ and amicrofilaremic individuals (Mp MF-) were obtained. Our data reveal that Mp MF+ individuals showed significantly reduced cytokine (IL-4, IL-6 and IL-12p70) and chemokine levels (IL-8 and RANTES), but significantly higher MIP-1β as well as increased <i>M</i>. <i>perstans</i>-specific IgG4 levels compared to Mp MF- individuals. In contrast, upon re-stimulation with worm antigen extract, IFN-γ, IL-13, IL-10 and IL-17A secretion was enhanced in cell cultures from Mp MF+ individuals when compared to those from cultures of healthy European individuals. Moreover, analysis of immune cell composition in peripheral blood from Mp MF+ individuals revealed increased type 2 helper T (Th2), natural killer (NK), regulatory B and T cell (Breg and Treg) subsets but decreased type 1 regulatory T (Tr1) cells. In summary, this study deciphers for the first time, <i>M</i>. <i>perstans</i>-specific immune responses using worm antigen extract and shows that patent <i>M</i>. <i>perstans</i> infections have distinct Th2, Breg and Treg subsets accompanied with reduced systemic innate and adaptive immune responses and dominant filarial-specific IgG4 levels.</p></div

Dominant <i>M</i>. <i>perstans</i>-specific IL-10, IFN-γ, IL-13 and IL-17A production by peripheral cells from <i>M</i>. <i>perstans</i> microfilaremic individuals.

<p>Freshly isolated peripheral whole blood cells (100μl/well) from <i>M</i>. <i>perstans</i> microfilaremic individuals (Mp MF+; n = 9) and healthy European non-endemic normals (NEN; n = 4) were cultivated in 10% BCS/RPMI-1640 medium (100μl/well) and left either un-stimulated (Cntl) or cultured with <i>M</i>. <i>perstans</i>-derived worm antigen extract (Mp Ag, 50μg/ml) at 37°C for 72 hours. Thereafter, culture supernatants were analysed for levels of (<b>A</b>) IFN-γ, (<b>B</b>) IL-4, (<b>C</b>) IL-5 (<b>D</b>) IL-13, (<b>E</b>) IL-10 and (<b>F</b>) IL-17A by ELISA. Graphs show box whiskers with median, interquartile ranges and outliers. Statistical significances between the indicated groups were obtained using the Kruskal-Wallis-test and, if significant, followed by a Dunn`s multiple comparison test for further comparison of the groups.</p

Correlation between ICT positivity rate and <i>L</i>. <i>loa</i> Mf prevalence.

<p>Correlation between ICT positivity rate and <i>L</i>. <i>loa</i> Mf prevalence.</p

Logistic regression analysis of ICT results according to <i>L</i>. <i>loa</i> load among the Mf carriers.

<p>Numbers in brackets are percentages.</p><p>Logistic regression analysis of ICT results according to <i>L</i>. <i>loa</i> load among the Mf carriers.</p

Infection profile of ICT positives cases with respect to <i>L</i>. <i>loa</i> and <i>M</i>. <i>perstans</i> infection status using day blood.

<p>Infection profile of ICT positives cases with respect to <i>L</i>. <i>loa</i> and <i>M</i>. <i>perstans</i> infection status using day blood.</p

Percentage of positive results using ICT card according to the <i>L</i>. <i>loa</i> load of microfilariae.

<p>R = 0.438; p < 0.001</p><p>Percentage of positive results using ICT card according to the <i>L</i>. <i>loa</i> load of microfilariae.</p