Involvement of BAFF and APRIL in Resistance to Apoptosis of Acute Myeloid Leukemia.

B-cell activation factor of the TNF family (BAFF), and a proliferation-inducing ligand (APRIL), two members of the tumour necrosis factor (TNF) superfamily, beyond playing a significant role in normal B-cell development, promote survival and proliferation of malignant B cells. Both ligands interact with 3 receptors: BAFF-R, specific to BAFF, and TACI and BCMA which are shared by both BAFF and APRIL. Here we wished to investigate the potential role of these proteins in resistance of acute myeloid leukaemia (AML) blasts to apoptosis. We found that the levels of both mRNA and proteins of APRIL, BAFF and their receptors were expressed in leukaemic cells of 24 newly diagnosed, untreated AML patients. We also demonstrated that patients who did not further respond to induction therapy (NR) presented with significantly higher baseline APRIL and BAFF expression on AML blasts as compared to these subjects who, after induction, achieved complete remission (CR) following induction therapy. Moreover, we observed striking differences in baseline levels of BCMA between CR and NR patients as we did not find detectable expression of this receptor in the latter group of patients. Interestingly, we found that AML blasts collected at baseline from NR patients cultured in presence of exogenous BAFF and APRIL were significantly more resistant to spontaneous or drug-induced apoptosis as compared with cells derived from CR patients. Altogether, our data confirm that BAFF and APRIL signaling play important role in AML pathogenesis and susceptibility to cytotoxic therapy while measuring of BCMA expression on AML cells can become a novel prognostic factor for chemotherapy response.

Decreased proportions of CD4 + IL17+/CD4 + CD25 + CD127- and CD4 + IL17+/CD4 + CD25 + CD127 - FoxP3+ T cells in children with autoimmune thyroid diseases (.).

Until now, altered balance of Th1 and Th2 immune cells has been postulated to play an important role in the pathogenesis of autoimmune thyroid diseases (AITD). However, recent studies on thyroid diseases have suggested a new role for Th17 cells that have been classified as a new lineage, distinct from Th1, Th2 and Treg cells. Despite wide interest, the role of Th17 cells in the pathogenesis of inflammatory and autoimmune diseases is still debated. The aim of the study was to estimate the proportions of Th17/Treg T cells in peripheral blood from patients with Graves' disease (GD; n = 29, mean age 15.4 ± 5.1 years), Hashimoto's thyroiditis (HT; n = 39, mean age 15.2 ± 4.1 years) and in healthy controls (n = 49, mean age 14.8 ± 3 years). Polychromatic flow cytometry and several fluorochrome-conjugated monoclonal antibodies were applied to delineate Th17 and Treg cells. The analysis of Th17/Treg T cell proportions in peripheral blood from patients with Graves' disease revealed significantly lower ratios of CD4 + IL17+/CD4 + CD25 + CD127 - (p < 0.0021) and CD4 + IL17+/CD4 + CD25 + CD127 - FoxP3 + (p < 0.0031) than in the control group. In addition, in the case of HT, we observed a significant decrease in the ratios of CD4 + IL17+/CD4 + CD25 + CD127 - (p < 0.0001) and CD4 + IL17+/CD4 + CD25 + CD127 - FoxP3 + (p < 0.0001) T cells in comparison to healthy children. In patients with untreated GD, a statistically significant positive correlation was found between the proportions of CD4 + IL17+/CD4 + CD25 + CD127-, CD4 + IL17+/CD4 + CD25 + CD127 - FoxP3+ T cells and the TRAbs (R = 0.71, p < 0.029; R = 0.72, p < 0.026, respectively) and a positive correlation was noted between the percentage of CD4 + CD - IL - 17 + T cells and the level of TSAbs (R = 0.66, p < 0.037). We conclude that the changes in the proportion of Th17/Treg T cells in peripheral blood and their significant relationship with the level of anti-thyroid antibodies indicate an involvement of these cells in the pathogenesis of AITD.

Effect of Periodic Granulocyte Colony-Stimulating Factor Administration on Endothelial Progenitor Cells and Different Monocyte Subsets in Pediatric Patients with Muscular Dystrophies.

Muscular dystrophies (MD) are heterogeneous group of diseases characterized by progressive muscle dysfunction. There is a large body of evidence indicating that angiogenesis is impaired in muscles of MD patients. Therefore, induction of dystrophic muscle revascularization should become a novel approach aimed at diminishing the extent of myocyte damage. Recently, we and others demonstrated that administration of granulocyte colony-stimulating factor (G-CSF) resulted in clinical improvement of patients with neuromuscular disorders. To date, however, the exact mechanisms underlying these beneficial effects of G-CSF have not been fully understood. Here we used flow cytometry to quantitate numbers of CD34+ cells, endothelial progenitor cells, and different monocyte subsets in peripheral blood of pediatric MD patients treated with repetitive courses of G-CSF administration. We showed that repetitive cycles of G-CSF administration induced efficient mobilization of above-mentioned cells including cells with proangiogenic potential. These findings contribute to better understanding the beneficial clinical effects of G-CSF in pediatric MD patients.

Prognostic significance of PD-1 expression on peripheral blood CD4+ T cells in patients with newly diagnosed chronic lymphocytic leukemia.

INTRODUCTION: Recent studies in a mouse model of chronic lymphocytic leukemia (CLL) demonstrated that inhibition of the programmed death receptor 1 (PD­1)-PD­L1 axis resulted in correction of leukemia­induced CD8+ T cell­related immune dysfunction and protected mice against CLL development. However, it remains unclear whether CLL development and progression can be also associated with CD4+ T cells expressing PD­1. OBJECTIVES: We aimed to analyze whether a quantitative assessment of CD4+PD­1+ T cells performed at the time of diagnosis can have prognostic significance in patients with CLL. PATIENTS AND METHODS: We examined 56 patients with newly diagnosed CLL at different stages of the disease. The quantitative assessment of PD­1­expressing CD4+ T cells was performed in all patients, using multicolor flow cytometry. RESULTS: We demonstrated that CLL patients with an advanced (high and intermediate risk) stage had a significantly higher number of CD4+PD­1+ T cells compared with subjects with low­grade disease. Importantly, we showed that the number of PD­1­expressing CD4+ T cells in the peripheral blood of patients referred for immediate treatment due to the advanced stage of the disease was significantly higher compared with subjects on watchful waiting. Finally, we found that treatment­naive patients with higher numbers of CD4+PD­1+ T cells at baseline showed a significantly shortened time to the first treatment compared with patients with a low number of CD4+PD­1+ T cells. CONCLUSIONS: Our study showed that the quantative assessment of CD4+PD­1+ T cells in peripheral blood using flow cytometry can facilitate prognostication of patients with newly diagnosed CLL.

Circulating classical CD14++CD16- monocytes predict shorter time to initial treatment in chronic lymphocytic leukemia patients: Differential effects of immune chemotherapy on monocyte-related membrane and soluble forms of CD163.

Three main monocyte subsets: classical CD14++CD16-, intermediate CD14++CD16+ and non-classical CD14+CD16++, differentially regulate tumor growth and survival. Thereby, in the present study we aimed to determine the role of distinct monocyte subsets in the prognostication of chronic lymphocytic leukemia (CLL). Moreover, we set out to analyze the effects of standard immune chemotherapy on different monocyte subsets and levels of membrane-associated and soluble forms of CD163, a monocyte/macrophage-related immunomodulatory protein. We demonstrated that the number of peripheral blood classical CD14++CD16- monocytes assessed at the time of diagnosis was negatively correlated with lymphocytosis and was decreased in the CLL patients who required immediate treatment as opposed to patients who qualified to 'watch and wait' strategy. Notably, lower baseline levels of classical CD14++CD16- monocytes in CLL patients who were qualified for 'watch and wait' therapy were associated with shorter time to initial treatment. Notably, therapy with rituximab, cyclophosphamide and fludarabine resulted in a significant reduction in the number of non-classical CD14+CD16++ monocytes and soluble form of CD163 but upregulation of membrane-associated monocyte CD163. Our data indicate that distinct monocyte subsets and two forms of CD163 are differentially modulated by both CLL and immune chemotherapy. Moreover, we proposed that quantification of classical monocytes at the time of diagnosis contributes to better prognostication of CLL patients.

Vitamin D3 Treatment Decreases Frequencies of CD16-Positive and TNF-α-Secreting Monocytes in Asthmatic Patients.

BACKGROUND: Previously, we demonstrated that glucocorticoid (GC) treatment of asthmatic patients resulted in decreasing frequencies of monocyte subsets expressing CD16 and capable of releasing TNF-α. Here, we wished to analyze whether the active form of vitamin D, i.e. vitamin D3, referred to as 1α,25-dihydroxyvitamin D3 [1,25-(OH)2D3] can exert GC-like proapoptotic effects on CD16-positive monocytes and thus decrease the proinflammatory potential of these cells. Finally, we set out to investigate whether the addition of 1,25-(OH)2D3 would facilitate the use of lower doses of GC without decreasing their anti-inflammatory properties. METHODS: Peripheral blood mononuclear cells collected from healthy individuals and asthmatic patients were cultured with 1,25-(OH)2D3 and/or varying doses of GC in the presence or absence of caspase inhibition. The cells were either directly stained for extracellular markers or prestimulated with lipopolysaccharide for the assessment of intracellular cytokine production and then analyzed by flow cytometry. RESULTS: We found that 1,25-(OH)2D3 alone (and in combination with GC) decreased the frequency of CD14++CD16+ and CD14+CD16++ monocytes from asthmatic patients and significantly diminished TNF-α production by the monocytes. With regard to the CD14+CD16++ subset, the monocyte-depleting effects of 1,25-(OH)2D3 were abrogated in the presence of pan-caspase inhibitor, suggesting a proapoptotic mechanism of 1,25-(OH)2D3 action. Interestingly, we found that a combined treatment of 1,25-(OH)2D3 and GC allowed for a 5-fold reduction of the GC dose while maintaining their anti-inflammatory effects. CONCLUSIONS: This study has revealed novel immunomodulatory properties of 1,25-(OH)2D3 directed against monocyte subsets capable of TNF-α production. In addition, our data suggest that the introduction of 1,25-(OH)2D3 to anti-inflammatory therapy would possibly allow for the use of lower doses of GC.