Giuseppe Gambino

CD4+ CCR5+ and CD4+ CCR3+ lymphocyte subset and monocyte apoptosis in patients with acute visceral leishmaniasis

The potential involvement of apoptosis in the pathogenesis of visceral leishmaniasis (VL) was examined by studying spontaneous and Leishmania antigen (LAg)‐induced apoptosis using cryopreserved peripheral blood mononuclear cells (PBMC) of Sicilian patients with VL. Results indicate that monocytes and T lymphocytes from acute VL patients show a significantly higher level of apoptosis compared with that observed in healed subjects. The percentage of apoptotic cells was higher in monocytes than in T lymphocytes. T cells involved in programmed cell death (PCD) were mainly of the CD4+ phenotype. In particular, the T helper 1‐type (Th1) subset, as evaluated by chemokine receptor‐5 (CCR5) expression, is involved in this process. Cell death in Th1‐type uses a CD95‐mediated mechanism. Furthermore, Th1‐type CCR5+ cells are prone to cell suicide in an autocrine or paracrine way, as attested by enhanced expression of CD95L in acute VL patients. The reduction in Th1‐type cells by apoptosis was confirmed by the decrease in interferon‐γ secretion. In conclusion, apoptosis of monocytes, CD4+ and CD4+ CCR5+ T cells could be involved in the failure of cell mediated immunity that is responsible for severe immune‐depression in VL.

IL-15 in human visceral leishmaniasis caused by Leishmania infantum

Interleukin (IL)‐15 is a recently discovered cytokine with the ability to stimulate the proliferation activity of Th1 and/or Th2 lymphocytes. Here, we investigated the involvement of IL‐15 in the immune response to Leishmania infantum infection by studying patients with visceral leishmaniasis (VL). We found that IL‐15 is produced by leishmanial antigen (LAg)‐stimulated peripheral blood mononuclear cells (PBMC) from active VL patients at a significantly higher level than those produced by cells from healed VL subjects or healthy controls. A significant increase in IL‐15 serum blood levels was also observed in acute VL patients compared with healed ones. Furthermore, recombinant IL‐15 had an appreciable effect in vitro in reducing IL‐4 and increasing the production of IL‐12 in response to LAg, but it was ineffective in altering the production of interferon‐γ (IFN‐γ). The production of endogenous IL‐15 in acute VL patients appeared to be insufficient to activate both IFN‐γ and IL‐12, as attested by the absence of modification of these two cytokines by neutralization experiments in the presence of anti‐IL‐15 monoclonal antibodies (MoAB). On the contrary, the neutralization of IL‐15 increased IL‐4 production. Together, these results indicate that endogenous IL‐15 plays a role in the suppression of Th2‐type cytokines, even though it does not enhance the production of Th1 cytokines in acute VL patients. Since IL‐15, in the presence of anti‐IL‐4 MoAb, caused a further increase in IL‐12 production and led to a significant production of IFN‐γ, one of its indirect effects on Th1 cell activation could be due to the latter’s effect on Th2 cytokines such as IL‐4. Therefore, our observations indicate that there is a potential for IL‐15 to augment the T‐cell response to human intracellular pathogens.

The significance of serum soluble IL-2 receptor as a marker for active visceral leishmaniasis in Sicilian patients.

Sera from nine Sicilian patients with confirmed visceral leishmaniasis (Leishmania donovani infantum; VL), at the moment of the diagnosis, during the course of the disease and after clinical recovery, were analysed for the concentration of soluble IL‐2 receptor (sIL‐2R). The results show that sIL‐2R is a marker of disease activity, since it is in high concentration at the beginning of infection and returns to the normal range following successful chemotherapy. At the same time of serum analysis for sIL‐2R, peripheral blood mononuclear cells (PBMC) of VL patients were stimulated with phytohaemagglutinin (PHA) or antigen and supernatant tested for IL‐2 and interferon‐gamma (IFN‐γ) production. Data demonstrate that there is an inverse relation between concentration of IL‐2 and IFN‐γ in the supernatants and sIL‐2R secretion in the sera.

Visceral adiposity index and DHEAS are useful markers of diabetes risk in women with polycystic ovary syndrome.

OBJECTIVE On the basis of the known diabetes risk in polycystic ovary syndrome (PCOS), recent guidelines of the Endocrine Society recommend the use of an oral glucose tolerance test (OGTT) to screen for impaired glucose tolerance (IGT) and type 2 diabetes (T2DM) in all women with PCOS. However, given the high prevalence of PCOS, OGTT would have a high cost-benefit ratio. In this study, we identified, through a receiver operating characteristic analysis, simple predictive markers of the composite endpoint (impaired fasting glucose (IFG) or IGT or IFG+IGT or T2DM) in women with PCOS according to the Rotterdam criteria. DESIGN We conducted a cross-sectional study of 241 women with PCOS in a university hospital setting. METHODS Clinical, anthropometric, and metabolic (including OGTT) parameters were evaluated. The homeostasis model assessment of insulin resistance (HOMA2-IR), the Matsuda index of insulin sensitivity, and the oral dispositional index and visceral adiposity index (VAI) were determined. RESULTS Out of 241 women included in this study, 28 (11.6%) had an IFG, 13 (5.4%) had IGT, four (1.7%) had IFG+IGT, and four (1.7%) had T2DM. Among the anthropometric variables examined, the VAI had a significantly higher C-statistic compared with BMI (0.760 (95% CI: 0.70-0.81) vs 0.613 (95% CI: 0.54-0.67); P=0.014) and waist circumference (0.760 (95% CI: 0.70-0.81) vs 0.619 (95% CI: 0.55-0.68); P=0.028). Among all the hormonal and metabolic serum variables examined, DHEAS showed the highest C-statistic (0.720 (95% CI: 0.65-0.77); P<0.001). CONCLUSIONS In addition to fasting glucose, the VAI and DHEAS may be considered useful tools for prescreening in all women with PCOS without the classical risk factors for diabetes.

Evaluation of serum levels of soluble CD4, CD8 and β2-microglobulin in visceral human leishmaniasis

The levels of soluble CD4 (sCD4), sCD8 and β2‐microglobulin (β2‐M) were measured in sera from patients with visceral leishmaniasis during the course of infection. Levels of sCD4. sCD8 and β2‐M were raised significantly above levels In normal sera and returned to the normal range after recovery. The decrease in the levels of CDS was related to a reduction of anaemia, leukopenia and thrombocytopenia. In contrast, sCD4 levels fluctuated during the period of infection. β2‐M returned within normal range more rapidly than sCD8 secretion. Our results suggest that T cells are activated during infection, and that it is also possible that the raised levels of these soluble molecules play a role in the impairment of protective immunity.

Modifications of general parameters of immune activation in the sera of Sicilian patients with Boutonneuse fever

The serum levels of β2‐microglobulin (β2‐M), soluble HLA class I antigen (sHLA‐I), soluble CD4 (sCD4) and CD8 (sCD8) were studied in 98 Sicilian patients with Boutonneuse fever (BF). In different stages of infection all markers were significantly increased in sera from Sicilian patients with acute BF compared with healthy controls. sCD8 and sHLA‐I reached the peak in the second week after the onset of symptoms, whereas sCD4 and β2‐M reached the peak in the first week. Afterwards sCD8 decreased to the levels of controls within the third week, the other parameters decreased later and were unmodified until the third week of infection. Significant correlations were found between sCD4 and sCD8 and the sIL‐2R, as well as between serum levels of β2‐M and sCD8. The reduction of CD3+ and CD4+ and the increase of CD8+ T cells in the blood indicate that these cells are involved in the response to rickettsia, and their activation might be in part responsible for the release of sCD4 and sCD8. Our data suggest that these soluble markers, indexes of immune activation of T cells both in the circulation and the affected tissues, may be used in monitoring BF evolution.