Salt-extractable antigen from Brucella melitensis 16M (RCM-BM) was used to evaluate the immune response from acute and chronic patients suffering from Brucella infections (in Mexico); their responses were compared with those of healthy controls. As a readout we used upregulation of CD69 (a well-established early activation marker for lymphocytes), lymphocyte proliferation by 3[H]thymidine or 5-bromo-2-deoxyuridine (BrdU) incorporation measured by liquid scintillation or flow cytometry, respectively, and production of gamma interferon (IFN gamma). We compared the antigen-specific response with the response induced by phytohaemagglutinin (PHA) as a positive control. There was no difference between acute patients and the healthy controls in the percentages of CD3+, CD4+ or CD8+ lymphocytes. However, we found that chronic patients had a significant (P < 0.05) increase in the CD8+ T cells, in line with previous studies. Antigen-specific responses to RCM-BM showed a significant (P < 0.05) upregulation of CD69 in both CD4+ and CD8+ T lymphocytes in acute brucellosis patients and in CD8+ T lymphocytes in chronic patients, indicating that both populations became activated by this antigen preparation. Moreover, lymphocyte proliferation from both acute and chronic patients in response to RCM-BM was highly significant (P < 0.001) when compared with healthy controls. However, there were no apparent differences between acute and chronic patients. Although the incorporation of BrdU showed similar results it provided additional information, since we demonstrated that both CD4+ and CD8+ T lymphocytes from acute and chronic patients proliferated equally well in response to RCM-BM. Similar results were observed with intracellular IFN gamma determination. As a whole, our data suggest an important role for both CD4+ and CD8+ T lymphocytes in Brucella infection in humans. As has been reported in mice, it is feasible that activated CD8+ T cells participate in protection against Brucella in humans through cytotoxicity or/and by the production of factors such as interferon and granulysin. The role of these cells should be carefully analysed to understand better their participation in human infection by Brucella.

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Abstract. Establishing the safety of non-caloric sweetener consumption in humans is a difficult task, since many contradictory results have been reported. The objective of this study was to compare the effect of frequent intake of sucrose, sucralose or steviol glycosides, on selected anthropometric, biochemical and immunological parameters in healthy, young adults. 38 individuals with normal body mass index were recruited and randomly divided into three experimental groups. After a washout week (where food with added sweeteners was restricted), each group was supplemented with sucrose (8 × 5 g packets/day), sucralose or steviol glycosides (4 × 1 g packets/day each) for 6 weeks. Selected variables were measured before and after treatment in each group and differences within and among groups were assessed. Our results showed that, compared to baseline, there was a modest but significant increase in weight (p = 0.0293) in the sucralose group, while the steviol glycosides group reduced their fat mass (p = 0.0390). No differences were observed in glycaemia; however, there was a significant increase in serum triglycerides (77.8–110.8 mg/dL) and cholesterol (162.0–172.3 mg/dL) in the sucrose group, whereas the steviol glycosides group presented lower triglycerides (104.7–92.8 mg/dL) and TNF-α concentrations (51.1–47.5 pg/mL). Comparison among groups showed differences in serum triglycerides (p = 0.0226), TNF-α (p = 0.0460) and IL-β (p = 0.0008). Our results suggest that, even in a short time span, frequent intake of steviol glycosides may have positive effects on metabolic parameters that may be relevant for human health.

CD8+ T cells that secrete proinflammatory cytokines play a central role in exacerbation of inflammation; however, a new subpopulation of CD8 regulatory T cells has recently been characterized. This study analyzes the prominent role of these different subpopulations in the development of graft-versus-host disease (GVHD). Samples from 8 healthy donors mobilized with Filgrastim® (G-CSF) and 18 patients who underwent allogeneic hematopoietic stem cell transplantation (HSCT) were evaluated by flow cytometry. Mobilization induced an increase in Tc1 (p < 0.01), Th1 (p < 0.001), Tc17 (p < 0.05), and CD8+IL-10+ cells (p < 0.05), showing that G-CSF induces both pro- and anti-inflammatory profiles. Donor-patient correlation revealed a trend (p = 0.06) toward the development of GVHD in patients who receive a high percentage of Tc1 cells. Patients with acute GVHD (aGVHD), either active or controlled, and patients without GVHD were evaluated; patients with active aGVHD had a higher percentage of Tc1 (p < 0.01) and Tc17 (p < 0.05) cells, as opposed to patients without GVHD in whom a higher percentage of CD8 Treg cells (p < 0.01) was found. These findings indicate that the increase in Tc1 and Tc17 cells is associated with GVHD development, while regulatory CD8 T cells might have a protective role in this disease. These tests can be used to monitor and control GVHD.