Patients with strongyloidiasis and HTLV-1 co-infection (n = 12) had more <i>Strongyloides stercoralis</i> larvae found in stool when compared to strongyloidiasis-only patients (n = 25).

<p>A semi-quantitative measure of <i>Strongyloides stercoralis</i> parasite load was determined at the time of diagnosis according to the number of larvae observed in stool sediment after Baermann concentration (range from1+ to 4+). Parasite load determination was made before the HTLV-1 status was known. HTLV-1 carriers had higher parasite loads (3+ and 4+) when compared to the non HTLV-1 group (10 out of 12 vs. 4 out of 25 respectively; p<0.001, Chi square test, Lima, Peru).</p

Increased proportions of regulatory T cells in strongyloidiasis/HTLV-1 co-infected patients.

<p>Comparison of regulatory T cell proportions (CD25+FoxP3+ among CD4+ T-cells) between healthy controls (blue, n = 17), patients with strongyloidiasis without HTLV-1 infection (red, n = 27), HTLV-1 asymptomatic carriers (orange, n = 9) and strongyloidiasis/HTLV-1 co-infected patients (green, n = 13). Co-infected patients had a significant increase of regulatory T cells compared to non-HTLV-1 patients. (* = P<0.05, One-way ANOVA). Lima, Peru.</p

Blood analysis, flow cytometry and interleukin-5 responses to <i>Strongyloides stercoralis</i> larval antigens A peripheral blood sample was obtained at enrollment from all strongyloidiasis patients.

<p>Samples were analyzed before HTLV-1 status was known. Numbers represent median of all parameters analyzed. Complete peripheral blood cell count showed lower hemoglobin and hematocrit levels in the HTLV-1 co-infected group. White blood cell, neutrophil, eosinophil, and lymphocyte proportions were not significantly different among groups, although a tendency to lower absolute eosinophil count was observed in the HTLV-1 infected group. Regulatory T cells were significantly increased in patients with strongyloidiasis and HTLV-1 co-infection (* = p<0.05, One way ANOVA, Lima, Peru).</p

IL-5 responses to larval <i>Strongyloides stercoralis</i> antigens are decreased in patients with strongyloidiasis and HTLV-1 co-infection (n = 13) compared to HTLV-1 negative subjects with strongyloidiasis (n = 27).

<p>Peripheral blood mononuclear cells from newly diagnosed strongyloidiasis patients were cultured with or without <i>Strongyloides stercoralis</i> infective-stage larval antigen. Culture supernatants were analyzed for IL-5 production. Patients with HTLV-1 co-infection had significantly decreased IL-5 responses (* p = 0.0004, Mann Whitney test).</p

Demographics and frequency of clinical signs and symptoms of strongyloidiasis patients with and without HTLV-1 co-infection.

<p>Clinical data was obtained from newly diagnosed patients with strongyloidiasis by stool modified Baermann sedimentation method and tested for HTLV-1 co-infection. Age and gender were similar among strongyloidiasis patients with or without HTLV-1 co-infection. Gastrointestinal signs and symptoms were more frequently reported among HTLV-1 co-infected patients. Table shows proportion of patients reporting symptoms. Frequencies were compared between <i>S. stercoralis</i> groups by Chi square test, * = p<0.05 (Lima, Peru).</p

Flow cytometry analysis showing increased proportions of CD4+CD25hi T cells and CD4+CD25+FoxP3+ regulatory T cells in peripheral blood of patients with strongyloidiasis and HTLV-1 co-infection.

<p>Representative flow cytometry analysis of peripheral blood mononuclear cells comparing a patient with strongyloidiasis without HTLV-1 co-infection (left) to strongylioidiasis/HTLV-1 co-infected patient (right). Upper figures show CD4 and CD25 staining of cells within the lymphocyte gate. Note population of CD4+CD25hi cells in the HTLV-1 co-infected patient suggesting regulatory T cell phenotype. Lower figures show CD4+ lymphocytes stained with CD25 and intracellular staining with FoxP3 confirming that CD4+CD25hi cells are indeed FoxP3+ (regulatory T cells).</p

Increased numbers of regulatory T cells correlates with reduced IL-5 responses to <i>Strongyloides stercoralis</i> larval antigens.

<p>Patients with higher regulatory T cell numbers showed lower IL-5 responses to <i>Strongyloides stercoralis</i> infective-stage crude antigen. An inverse correlation was determined by Sperman non-parametric correlation analysis (Spearman r = −0.38, p = 0.03).</p

AA, but not IFN-α, induces cell death in HAM/TSP PBMCs.

<p>HAM/TSP PBMCs (n = 6) were treated for 72 hours in the absence or presence of low-dose AA (10 µg/ml), high-dose AA (100 µg/ml) or IFN-α2A (1000 IU/ml). (A) The percentage of cell death was quantified by trypan blue dye exclusion and is shown in the <i>y</i>-axis, whereas the treatment conditions are shown in the <i>x</i>-axis. The one-sample t-test p-values are indicated by asterisks (^*<0.05, ^**<0.01 and ^***<0.001). (B) Fluorescence microscopy images of Hoechst 33342-stained PBMCs are shown for untreated (NT) and high-dose AA-treated PBMCs of one representative HAM/TSP patient (n = 3). Nuclear condensation and DNA fragmentation (f) was observed for AA-treated PBMCs.</p

Overview of the top 20 of the most significant down- and up-regulated genes by high-dose AA (100 µg/ml) in MT-2 cells.

<p>Overview of the top 20 of the most significant down- and up-regulated genes by high-dose AA (100 µg/ml) in MT-2 cells.</p

AA treatment dose-dependently induces cell death in HTLV-1-infected cell lines.

<p>HTLV-1-infected CD4+ T-cell lines were cultured for 48 hours with no treatment (NT), low-, intermediate-, high-dose AA (10, 50, 100 µg/ml) or IFN-α (1000 IU/ml). Flow cytometric quantification of cells with DNA degradation (Hoechst 33342-positive subdiploid cells) and proliferating cell nuclear antigen (PCNA)-positive cells are shown in the <i>y</i>-axis for both (A) MT-4 (n = 4) as well as (B) MT-2 cells (n = 3), whereas the treatment conditions are shown in the <i>x</i>-axis. ANOVA with Bonferroni post-test for multiple testing was used and the p-values are indicated by asterisks (^*<0.05, ^**<0.01 and ^***<0.001). (C) Confocal microscopy images of Hoechst 33342-stained MT-2 cells are shown for untreated and high-dose AA-treated MT-2 cells. Nuclear condensation (c) was observed for the AA-treated cells, whereas normal nuclei and mitosis (m) were observed for the untreated cells.</p