BTLA Expression in CLL: Epigenetic Regulation and Impact on CLL B Cell Proliferation and Ability to IL-4 Production.

In our previous study, while chronic lymphocytic leukemia (CLL) cases showed higher levels of B and T lymphocyte attenuator (BTLA) mRNA compared to controls, lower BTLA protein expression was observed in cases compared to controls. Hence we hypothesize that micro RNA (miR) 155-5p regulates BTLA expression in CLL. In line with earlier data, expression of BTLA mRNA and miR-155-5p is elevated in CLL (p = 0.034 and p = 0.0006, respectively) as well as in MEC-1 cell line (p = 0.009 and 0.016, respectively). Inhibition of miR-155-5p partially restored BTLA protein expression in CLL patients (p = 0.01) and in MEC-1 cell lines (p = 0.058). Additionally, we aimed to evaluate the significance of BTLA deficiency in CLL cells on proliferation and IL-4 production of B cells. We found that secretion of IL-4 is not dependent on BTLA expression, since fractions of BTLA positive and BTLA negative B cells expressing intracellular IL-4 were similar in CLL patients and controls. We demonstrated that in controls the fraction of proliferating cells is lower in BTLA positive than in BTLA negative B cells (p = 0.059), which was not observed in CLL. However, the frequency of BTLA positive Ki67+ B cells in CLL was higher compared to corresponding cells from controls (p = 0.055) while there were no differences between the examined groups regarding frequency of BTLA negative Ki67+ B cells. Our studies suggest that miR-155-5p is involved in BTLA deficiency, affecting proliferation of CLL B cells, which may be one of the mechanisms responsible for CLL pathogenesis.

Imbalance in PB IL-17-Secreting and Regulatory Cells in Pars Planitis Is Associated with Dysregulation of IFN-γ-Secreting Cells, Especially in Patients with Clinical Complications.

RESULTS: In patients, an increase in the population of Th17-secreting cells negatively correlated with the abundance of both IFN-γ-producing and T regulatory as well as suppressor cells, regarding all the phenotypes studied. Although a strong dependence of the PB Th1 cell compartment on the duration of the disease was observed, it was limited to the subgroup of patients with macular edema only. The frequency of B regulatory cells was unchanged compared to controls. CONCLUSIONS: In pars planitis, the alterations in lymphocyte cell distribution affect primarily the T cell repertoire. The imbalance in PB Th1/Th17/Treg cells creates proinflammatory conditions, strengthening the suggestion that the immune background may play a role in pars planitis pathogenesis. Also, circulating Th1 level may be of potential clinical relevance in terms of prediction of a more severe course of the disease.

CD4+CD28null T cells are expanded in moderately active systemic lupus erythematosus and secrete pro-inflammatory interferon gamma, depending on the Disease Activity Index.

BACKGROUND: Pathogenic CD4+CD28null cells are characterized by inflammatory cytokine synthesis and tropism to the inflamed tissues. Recent studies showed the involvement of CD28null T cells in a severe clinical outcome of lupus. However, their role in moderately active disease is still unresolved. METHODS: We examined the levels of circulating CD4+CD28null cells and CD8+CD28null suppressor T cells. We also compared the CD4+CD28null and CD4+CD28+ T-cell functional properties, including the expression of interferon gamma (IFN-γ) and Ki67 among systemic lupus erythematosus (SLE) patients (n = 20) and healthy controls (n = 20). All the patients were under immunosuppressive treatment and exhibited moderate SLE activity (median SLE Disease Activity Index (SLEDAI) = 6). RESULTS: In patients, we found elevated CD4+CD28null and unchanged levels of suppressor CD8+CD28null T cells. There was no difference between patients and controls in IFN-γ and Ki67-expressing CD4+, CD4+CD28+, and CD4+CD28null T cells, except for higher IFN-γ levels in CD4+CD28+ T cells in SLE. In each studied group, we observed a higher preponderance of IFN-γ- and Ki67-expressing cells among CD4+CD28null T cells and lower levels of IFN-γ in CD4+CD28null T cells compared to the CD28+ subset. Similarly, Ki67 intensity was decreased in healthy CD4+CD28null cells, whereas in patients, comparably high expression was observed in both subsets. IFN-γ intensity in CD4+CD28null T cells correlated with SLEDAI. CONCLUSION: SLE with a moderately active clinical course is characterized by peripheral blood expansion of CD4+CD28null T cells and a normal abundance of suppressor CD8+CD28null T cells. The demonstration that these pathogenic CD4+ T cells, despite the lack of CD28, maintain the ability to produce pro-inflammatory IFN-γ positively correlated with disease activity as well as relatively high proliferative capacity may suggest their potentially predictive role in SLE flares.

Patients with chronic lymphocytic leukaemia (CLL) differ in the pattern of CTLA-4 expression on CLL cells: the possible implications for immunotherapy with CTLA-4 blocking antibody.

Recently, systemic administration of a human monoclonal antibody directed against cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) expressed on circulating T cells in patients with chronic lymphocytic leukaemia (CLL) has been considered. Also, CLL cells have been shown to express CTLA-4, increased levels of which in the leukaemic compartment are a predictor of good clinical outcome. Since both CLL and Treg microenvironment cells can be targeted by the CTLA-4 blocking antibody in this immunotherapy approach, the investigation of the functional effect of CTLA-4 blockade on CLL cells might be of potential clinical relevance. The main aim of this study was to examine the effect of CTLA-4 blockade on proliferation activity and apoptosis of CLL cells in patients with low and high CTLA-4 expression. We found that in the high CTLA-4-expressing CLL group, CTLA-4 blockade on the CLL cell surface resulted in a significant increase in the median percentages of Ki67(+) cells and a tendency to decrease in the proportion of apoptotic cells. In contrast, in the low CTLA-4 expressors, CTLA-4 blockade did not affect the proliferation activity or the frequency of apoptosis. This study reports for the first time the different effect of CTLA-4 blockade on CLL cells in CLL patients depending on the levels of CTLA-4 expression. CTLA-4 blockade seems to induce pro-survival signals in leukaemic cells from CLL patients exhibiting high CTLA-4 expression, suggesting that an immunotherapy approach based on the systemic use of monoclonal anti-CTLA-4 antibodies could be an unfavourable strategy for some CLL patients.

CTLA-4 affects expression of key cell cycle regulators of G0/G1 phase in neoplastic lymphocytes from patients with chronic lymphocytic leukaemia.

Previously, we showed that cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) is overexpressed in chronic lymphocytic leukaemia (CLL) and its expression is correlated with the expression of the major regulators of G1 phase progression: cyclins D2 and D3, and cyclin-dependent kinase inhibitory protein 1 (p27 (KIP1) ). In the present study, we blocked CTLA-4 on the surface of both CLL cells and normal B lymphocytes to investigate the impact of CTLA-4 on the expression of the mentioned G1 phase regulators. We found that in CLL patients and in healthy individuals, the median proportions of cyclin D2-positive cells as well as cyclin D3(+) cells significantly decreased following CTLA-4 blockade. Moreover, CTLA-4 blockade led to an increase in the median frequencies of p27 (KIP1) -positive cells, although this increase was marked only in CLL patients. Our study showed that CTLA-4 affects the expression of the key regulators of G1 phase progression in CLL cells as well as in normal B lymphocytes and may contribute to a better understanding of the role of CTLA-4 in the regulation of G1 phase progression.

Exogenous IL-2 controls the balance in Th1, Th17, and Treg cell distribution in patients with progressive rheumatoid arthritis treated with TNF-alpha inhibitors.

Interleukin-2 (IL-2) has been suggested to control Treg/Th17 balance. Recently, we reported a relationship of rheumatoid arthritis (RA) activity/progression with irreversible systemic Treg and Th1 defects including serum IL-2 shortage. Herein, we explore the role of in vitro stimulation with rIL-2 in the observed immune alterations reversal. Patients with stable or progressive RA were assigned to methotrexate (MTX) group or to TNF-alpha inhibitors (iTNF) group, respectively. Flow cytometric analyses were performed before and after 6 months of treatment. Circulating Th1, Th17, and Treg cells were determined before and after 72-h culture with anti-CD3 + rIL-2. Before therapy, 72-h stimulation restored recently observed phenotypic Th cell alterations, except for the enriched Th17 subset normalized as late as after therapy in all patients. Under 6-month therapy, anti-CD3 stimulation changed the Th cell distribution only in progressive RA; despite Th1 enrichment, it revealed Treg population defects, which were completely reversed by exogenous IL-2 added to the stimulating culture. Our paper shows that in aggressive RA patients exhibiting serum IL-2 shortage despite iTNF therapy, exogenous rIL-2 is capable of promoting Treg differentiation affected by chronic activation, thus supporting its use in the combined strategy of biologic treatment of the progressive form of RA.

Peripheral blood Th17/Treg imbalance in patients with low-active systemic lupus erythematosus.

INTRODUCTION: The balance between proinflammatory Th17 cells and regulatory T cells plays an important role in the pathogenesis of autoimmune diseases, including systemic lupus erythematosus (SLE). In particular, an increased ratio of Th17/Treg cells has been shown to correlate with active SLE and specific organ involvement. The aim of our study was to assess Th17 and Treg cell populations in peripheral blood (PB) of patients with clinically quiescent SLE, and to evaluate their correlation with organ involvement. MATERIAL/METHODS: We performed flow cytometric analysis of studied T CD4+ cell subpopulations in PB from 21 patients with SLE and 13 healthy controls. Disease activity was measured with the SELENA-SLEDAI index; organ involvement was divided into renal, neurological and hematological. RESULTS: A statistically significant difference (p<0.01) between the mean percentages of CD4+CD25highFoxP3+ Treg cells in SLE patients (18.57%) and healthy controls (32.08%) was observed. Similarly, proportions of functional CTLA-4+ Treg cells were markedly lower in SLE patients than in healthy controls--19.3% vs. 23.82% (p=0.03). In contrast, SLE patients exhibited a significantly increased frequency of circulating Th17 cells with the phenotype CD4+IL-17+ compared to controls--1.36 % vs 0.19% (p<0.01). Also the ratio of Th17 cells to Th1 cells was markedly higher in SLE patients than in the control group (p<0.01). We did not find any correlation of PB Th cell distribution with organ involvement in SLE patients examined. CONCLUSIONS: Our report showed for the first time that systemic Th17/Treg imbalance occurred also in patients with low disease activity and in remission. We suggest that immunological alterations may precede clinical and laboratory symptoms of the disease activity.

Alterations in both the activatory and inhibitory potential of peripheral blood CD4+ T cells in rheumatoid arthritis patients correlate with disease progression.

The chronic nature of rheumatoid arthritis (RA) suggests immune dysfunction, including persistent systemic activation. Therefore, we evaluated the activatory and inhibitory potential as well as proliferative activity of peripheral blood (PB) CD4+ T cells from RA patients in different stages of the disease and after different therapeutic interventions. We found that CD4+ T cells from RA patients were activated in vivo concerning decreased CD28 expression and increase of CD40L, CD69, and CTLA-4 expression; however, the extent of stimulation was suboptimal when compared to healthy controls. Consequently, impaired proliferative activities of these cells were found in all patients irrespective of the active disease duration. Treatment with methotrexate (MTX) and/or inhibitors of TNF-alpha (iTNF) did not significantly influence systemic activation in RA patients, which corresponded with the maintenance of inflammation markers; however, partial restoration of CD28 and CTLA-4 expression as well as clinical improvement were observed. In patients with early disease (the MTX group), we noted higher capacity of CD4+ T cells for restoration of T cell function, whereas cells from the iTNF group with progressive disease remained with a proliferative defect after the treatment. In conclusion, our study demonstrates that the dysregulated expression of molecules interfering with CD4+ T cell signaling may result in functional impairment of the effector T cells and correlates with disease progression.

Patients with the most advanced rheumatoid arthritis remain with Th1 systemic defects after TNF inhibitors treatment despite clinical improvement.

Systemic immune defects might reflect severely dysregulated control of chronic inflammation related to disease progression. Th17/Treg cell imbalance has been demonstrated to be involved in rheumatoid arthritis (RA) pathogenesis. Despite controversial results, a growing anti-inflammatory role in this process has been recently attributed to Th1 responses. The aim of the study was to estimate the extent of Th1/Th17/Treg imbalance in peripheral blood (PB) of patients with short- and long-term RA in relation to cytokine milieu and its reversal after therapy with methotrexate and/or TNF inhibitors, respectively. Patients with different duration of RA (median 6 vs. 120 months) in the active phase of RA were enrolled in this study. We performed flow cytometric analysis of PB Th1, Th17, and Treg populations together with estimation of serum cytokine concentrations using cytometric bead array. Disease activity was calculated on the basis of clinical and biochemical indices of inflammation (DAS28, ESR, CRP). All parameters were measured and correlated with each other before and after 6 months therapy. Elevated levels of circulating Th17 cells and IL-6 were found in all active patients, of which Th17 cells were down-regulated by the treatment. Significantly reduced Th1 and functional CTLA-4+ Treg cell frequencies as well as Th1 cytokines observed only in progressive RA seemed to be irreversible. Although therapy induced clinical improvement in almost all patients, those with advanced RA remained with signs of inflammation. Our report demonstrates that both the extent of systemic immune abnormalities and their restoration are dependent on duration of the active RA.

Dysregulated expression of both the costimulatory CD28 and inhibitory CTLA-4 molecules in PB T cells of advanced cervical cancer patients suggests systemic immunosuppression related to disease progression.

UNLABELLED: Cervical cancer (CC) occurs more frequently in women who are immunosuppressed, suggesting that both local and systemic immune abnormalities may be involved in the evolution of the disease. Costimulatory CD28 and inhibitory CTLA-4 molecules expressed in T cells play a key role in the balanced immune responses. There has been demonstrated a relation between CD28, CTLA-4, and IFN genes in susceptibility to CC, suggesting their importance in CC development. Therefore, we assessed the pattern of CD28 and CTLA-4 expression in T cells from PB of CC patients with advanced CC (stages III and IV according to FIGO) compared to controls. We also examined the ability of PBMCs to secrete IFN-gamma. We found lower frequencies of freshly isolated and ex vivo stimulated CD4 + CD28+ and CD8 + CD28+ T cells in CC patients than in controls. Loss of CD28 expression was more pronounced in the CD8+ T subset. Markedly increased proportions of CTLA-4+ T cells in CC patients before and after culture compared to controls were also observed. In addition, patients' T cells exhibited abnormal kinetics of surface CTLA-4 expression, with the peak at 24 h of stimulation, which was in contrast to corresponding normal T cells, revealing maximum CTLA-4 expression at 72 h of stimulation. Of note, markedly higher IFN-gamma concentrations were shown in supernatants of stimulated PBMCs from CC patients. CONCLUSIONS: Our report shows the dysregulated CD28 and CTLA-4 expression in PB T cells of CC patients, which may lead to impaired function of these lymphocytes and systemic immunosuppression related to disease progression.

Zeta chain expression in T and NK cells in peripheral blood of children with nephrotic syndrome.

The idiopathic nephrotic syndrome (INS) has been related to cellular immune disturbances. The zeta (zeta) chain, a component of the T-cell receptor/CD3 (TCR) complex and CD16 heterodimer in NK cells, plays a crucial role in T and NK cell activation and proliferation. The aim of our study was to examine zeta chain expression in CD4+, CD8+ T lymphocytes and NK cells in the peripheral blood of children with INS and to evaluate the effect of anti-CD3+rIL-2 stimulation on the level of zeta chain expression in the INS pediatric population. The study group consisted of 15 children with INS in relapse, 16 patients with INS in clinical remission, and 17 controls. The percentage of zeta-positive cells and the values of mean fluorescence intensity (MFI) were determined by flow cytometry. Compared with that in the controls, the percentage of zeta+ freshly isolated NK cells in children with INS in relapse was significantly lower, whereas, in CD3+/CD4+ and CD3+/CD8+ populations, no alteration was observed. There were no differences in the MFI values between the populations of freshly isolated cells either. Stimulation with anti-CD3+rIL-2 decreased the percentage of zeta+/CD4+ T cells and NKzeta+ cells in a significant way in all the groups analysed, whereas the percentage of zeta+/CD8+ T cells decreased significantly only in patients with INS in relapse. The altered pattern of zeta expression in fresh NK cells from children with INS in relapse, and the disturbed response of zeta+/CD8+ T cells to anti-CD3+rIL-2 stimulation in relapse, suggests the possible role of this chain in immune dysregulation in INS, particularly with regard to cytotoxic cells.

Impaired zeta chain expression and IFN-gamma production in peripheral blood T and NK cells of patients with advanced lung cancer.

Recent studies show that low expression of zeta chain in T and NK cell leads to impaired anti-tumour immunity in patients with cancer, poor prognosis, and shorter overall survival. Therefore, monitoring zeta chain expression may be useful in assessing immune competence in lung cancer patients and in following changes during anticancer therapies. Such studies concerning small-cell and non-small cell lung cancer (SCLC and NSCLC, respectively) have not been published so far. The expression of zeta chain and IFN-gamma in peripheral blood (PB) T and NK cells from SCLC and NSCLC patients at advanced (III, IV) stages were analysed before and after chemotherapy with etoposide and cisplatin using flow cytometry. Serum concentrations of TGF-beta1 and IL-10 were also estimated at each time point tested. Before therapy, impaired zeta chain expression was observed in all the patients corresponding with increased levels of immuno-suppressive cytokines in sera compared with controls. Decreased IFN-gamma production in T cells from all patients was also demonstrated. In NK cells, IFN-gamma was secreted at lower levels in NSCLC patients, while in the SCLC group it was normal. After chemotherapy, restoration of zeta expression in NK cells and its insignificant increase in T cells in SCLC patents corresponding with normalization of TGF-beta secretion were noted. In contrast, NSCLC patients retained impaired zeta expression in T and NK cells. SCLC and NSCLC patients showed a profound defect in IFN-gamma secretion in T and NK cells upon treatment. There were no differences in studied parameters between NSCLC and SCLC groups before and after chemotherapy. This is the first report of impaired zeta expression in PB T and NK cells in patients with SCLC and NSCLC in advanced stages, which may result from higher levels of immunosuppressive cytokines in sera. After cytostatic treatment, all the studied patients, including those with initial good response to chemotherapy, remained with profound abnormalities in T and NK cells, which could have dramatic consequences regarding severely impaired anti-tumour immunity.

Is cyclin D2 a marker of B-cLL cell activation?

The most recent studies emphasize a link between B-cell proliferation in vivo and clinical outcome of B-cell chronic lymphocytic leukemia (B-CLL). The expression of cyclin D2 in B-CLL cells isolated from the peripheral blood of 27 untreated patients in relation to the apoptosis ratio both before and 72 h after culture in the absence of growth factors was analyzed by immunocytochemistry. The significant associations between cell death in culture and both cyclin D2 expression in freshly isolated cells and the rate of its decrement in culture found in this study confirm the special role of cyclin D2 in enhancing the longevity of these cells in vivo. As cyclin D2 is inducible in the early G1 phase, its increased expression might also reflect the activation of cells attempting to replicate in vivo. Furthermore, the finding that B-CLL progression positively correlates with the gradual increase in the proportion of apoptotic B lymphocytes in culture seems to support the notion of cells striving to undergo division in the absence of growth factors. All together, these results indicate the possibility that cyclin D2+ cells represent a pool of leukemic cells with the potential to enter the dividing compartment.

[Expression of zeta (zeta) chain in peripheral blood T lymphocytes and NK cells of children with idiopathic nephrotic syndrome (INS)--preliminary results]. / Ekspresja lancucha zeta (zeta) na limfocytach T i komórkach NK krwi obwodowej u dzieci z idiopatycznym zespolem nerczycowym (IZN)--doniesienie wstepne.

UNLABELLED: Cellular immune disturbances have been implicated in the pathogenesis of idiopathic nephrotic syndrome. The zeta (zeta) chain, which is a component of the TCR/CD3 complex and CD16 heterodimer in NK cells, plays a crucial role in signal transducing events leading to T and NK cell activation and proliferation. The aim of our study was to examine the zeta (zeta) chain expression in peripheral blood CD4+, CD8+ T-lymphocytes and NK cells (CD3-/CD56+) derived from children with NS in active phase of the disease and in remission. We also examined the effect of 24 and 72 h anti-CD3+rIL-2 stimulation on the zeta chain expression in all studied groups. MATERIAL AND METHODS: The study group consisted of 8 children with INS in active phase of the disease, 11 children with INS in clinical remission and 15 age-matched healthy controls. The level of zeta (zeta) chain expression, assessed by flow cytometry, was determined as the mean fluorescence intensity (MFI). RESULTS: In INS patients with active phase MFI values for CD4+ cells were higher than in children with remission and in controls. The levels of zeta in CD4+ T-lymphocytes of patients with remission were comparable to those in controls. There were no differences between zeta levels on NK cells in examined groups. Ex vivo stimulation had no impact on zeta expression in children with acute phase of NS, whereas in patients on remission stimulation with anti-CD3+rIL-2 increased zeta expression on CD4+ cells and decreased it on NK cells. NK zeta expression was also diminished in the control group. CONCLUSIONS: Preliminary results point at the alterations of zeta expression in children with INS as a probable cause of immune dysregulation in this group of patients.

CD40L, CD28, and CTLA-4 expression on CD4+ T cells in kidney graft recipients: a relationship with post-transplantation clinical course.

BACKGROUND: Experimental studies have demonstrated that the intensity of alloreactivity against a transplanted organ results from an interaction of positive (CD40/CD40L and B.7/CD28) and inhibitory (B.7/CTLA-4) signals between antigen-presenting cells (APCs) and T lymphocytes. METHODS: We examined the CD40L, CD28, and both surface (s) and intracellular (i) CTLA-4 expressions on freshly drawn and anti-CD3+rIL-2-stimulated peripheral blood CD4+ T cells in groups of kidney transplant recipients in relation to distinct clinical course using the tri-color immunofluorescence method. RESULTS: The median proportions of freshly isolated CD3+/CD4+/CTLA-4+ and CD3+/CD4+/CD40L+ cells in all groups of graft recipients were higher than in control subjects. In patients with stable graft function (SGF), non-significantly higher sCTLA-4, significantly higher iCTLA-4 expression, and significantly lower CD40L expression on freshly drawn CD4+ T cells compared with recipients with chronic allograft nephropathy (CAN) were found. Moreover, CD4+ T cells from SGF patients showed a higher potential to express sCTLA-4 and CD40L molecules and to down-regulate the CD28 molecule in response to ex vivo stimulation than those from patients with CAN. In patients without acute graft rejection (NAGR), a markedly higher proportion of freshly drawn CD3+/CD4+/iCTLA-4+ cells compared with patients with acute graft rejection (AGR) and an up-regulation of the median percentage of CD3+/CD4+/CD40L+ cells after ex vivo stimulation was found. CONCLUSIONS: In patients with SGF, peripheral blood CD4+ T cells exhibited a higher potential to express surface CTLA-4 and CD40L and to down-regulate CD28 costimulatory molecules in response to ex vivo stimulation, indicating a relationship between the expression patterns of both costimulatory and inhibitory molecules in CD4+ T cells and clinical course after renal transplantation.