Absolute numbers of LDGs, CD14⁺ cells and white blood cells.

<p>The white blood cell counts were determined after Ficoll using trypan blue exclusion and are expressed as cell number per ml of blood.</p

Phenotype and frequency of arginase-expressing cells in PBMCs.

<p>PBMCs were isolated by density gradient from the blood of controls (n = 14), VL patients (n = 17) and treated VL patients (n = 12). The phenotype of arginase-expressing cells was determined by flow cytometry. (A) Dot plot profile of CD15⁺ arginase⁺ cells, data show the results of one representative experiment out of 17 independent experiments; (B) dot plot profile of CD14⁺ arginase⁺ cells, data show the results of one representative experiment out of 17 independent experiments. (C) Percentages of CD15⁺arginase⁺ cells in the PBMCs of controls (n = 14), VL patients (n = 17) and treated VL patients (n = 12). Box  =  interquartile range and median; whiskers = range. Statistical significance was determined by a two-tailed Mann-Whitney test. NS = not significant. Patients = VL patients before treatment; treated patients = VL patients after 3–4 weeks treatment.</p

Arginase activity in PBMCs.

<p>PBMCs were isolated by density gradient from the blood of controls (n = 10), VL patients (n = 14) and treated VL patients (n = 12) and the activity of arginase was measured by enzymatic assay. Box = interquartile range and median; whiskers = range. Statistical significance was determined by a two-tailed Mann-Whitney test. NS = not significant. Patients = VL patients before treatment; treated patients = VL patients after 3–4 weeks treatment.</p

Frequency of LDGs and monocytes in PBMCs.

<p>PBMCs were isolated by density gradient from the blood of controls (n = 14), VL patients (n = 17) and treated VL patients (n = 12), (A) the frequencies of monocytes were determined by flow cytometry and (B) the ratio of low-density granulocytes (LDGs) to monocytes was calculated by dividing the percentages of LDGs by the percentages of monocytes. Box = interquartile range and median; whiskers = range. Statistical significance was determined by a two-tailed Mann-Whitney test. NS = not significant. Patients = VL patients before treatment; treated patients = VL patients after 3–4 weeks treatment.</p

L-arginine levels and CD3ζ expression in CD4⁺ and CD8⁺ T cells.

<p>Plasma was isolated by centrifugation of the blood of controls (n = 11), VL patients (n = 11) and treated VL patients (n = 11) and (A) the levels of L-arginine were measured by HPLC. PBMCs were isolated by density gradient from the blood of controls (n = 10), VL patients (n = 10) and treated VL patients (n = 10) and the mean fluorescence intensity of CD3ζ was determined in CD4⁺ T cells (B) and CD8⁺ T cells (C). Box = interquartile range and median; whiskers = range. Statistical significance was determined by a two-tailed Mann-Whitney test. NS = not significant. Patients = VL patients before treatment; treated patients = VL patients after 3–4 weeks treatment.</p

Haematological data.

<p>Hct = hematocrit; Hb = haemoglobin.</p><p>Normal range: platelets (×10³) = 150–450; white blood cells (×10³) = 4.5–10.5; Hct (%) = 35–60; hb (g/dl) = 11–18.</p><p>The white blood cells were counted in total blood before Ficoll using a COULTER Ac•T diff Hematology Analyzer and are expressed as number of WBC (×10³) per µl of blood.</p

Clinical data.

<p>Spleen and liver size = measurement below left costal margin and right subcostal margin (respectively).</p

Arginase activity - a marker of disease status in patients with visceral leishmaniasis in ethiopia.

The underlying mechanisms resulting in the profound immune suppression characteristic of human visceral leishmaniasis (VL) are not fully understood. Here, we tested the hypothesis that arginase, an enzyme associated with immunosuppression, is higher in patients with VL and contributes to impaired T cell responses. We recruited patients with VL before and after treatment and healthy controls and measured the arginase metabolism in the blood of these individuals. Our results show that arginase activity is significantly higher in the blood of patients with active VL as compared to controls. These high levels of arginase decline considerably once the patients are successfully treated. We identified the phenotype of arginase-expressing cells among PBMCs as neutrophils and show that their frequency was increased in PBMCs of patients before treatment; this coincides with reduced levels of L-arginine in the plasma and decreased expression levels of CD3ζ in T cells