Generation of T regulatory cells in children with newly diagnosed type 1 diabetes mellitus.

UNLABELLED: There is increasing evidence that T-regulatory (Treg) cells could be used to prevent or cure autoimmune diseases including type 1 diabetes mellitus (T1DM). The aim of the present study was to verify the hypothesis that functional Treg cells can be generated from conventional T-cells separated from a small amount of peripheral blood of children with newly diagnosed T1DM (N=25). METHODS: CD4(+)CD25(-) cells were cultured with Treg expander (CD3/CD28) and IL-2 for generating de novo Treg cells. The assessment of the expression of selected genes and proteins critical to Treg function and the proliferation assays were performed with the use of real-time RT-PCR and flow cytometry. RESULTS: After a 4-week stimulation with Treg expander and IL-2, the percentage of T-regulatory cells was significantly higher compared to the cells treated with medium alone (with no difference between diabetic and control children). However, we found some disturbances in the gene expression at mRNA level for molecules crucial for T-reg function. The induced Tregs from diabetic and control children were fully functional as assessed in proliferation assays. IN SUMMARY: Despite some disturbances at mRNA level in the critical gene expression, the suppressive properties of induced Treg cells from diabetic and control children were effective.

Disturbances in some gene expression in T regulatory cells separated from children with metabolic syndrome.

The metabolic syndrome (MS) is defined as a cluster of risk factors, including abdominal obesity, dyslipidaemia, glucose intolerance and hypertension, which increase the risk for coronary heart disease. The immunological aspects of obesity and MS, including the role of T regulatory cells, have been intensively investigated. The aim of this study was to determine whether there is any disturbance in T regulatory cells number and/or function in children with MS. The percentages of T regulatory cells in the peripheral blood of children fulfilling the International Diabetes Federation criteria of the disease (n = 47) were assessed. Treg cells were also separated for further analysis of multiple genes important in their function with the use of real-time RT-PCR. We did not observe any difference in Treg percentages between study and control group but there was lower expression of some molecules including transforming growth factor-beta and interleukin-12 family members in Treg cells separated from children with MS compared to the healthy subjects. Our study is the first to report significant disturbances in some gene expression in T regulatory cells separated from children with MS. The results should be useful for further research in this field, including immunotherapeutic interventions.

Acute lymphoblastic leukemia-derived dendritic cells express tumor associated antigens: PNPT1, PMPCB, RHAMM, BSG and ERCC1.

In all types of leukemia both in children and adults there is a need for novel therapies that could reduce the risk of relapse after standard treatment. Acute lymphoblastic leukemia (ALL) cells are ineffective antigen presenting cells, but as shown by many authors including results from our laboratory, stimulation with CD40L restores their antigen expressing capacity. The development of T-cell therapies for leukemic patients can be based on discovery of leukemia-associated antigens (LAA) which could be recognized by the host immune system. The aim of our present study was to test the hypothesis that leukemia-derived dendritic cells maintain the expression of tumor associated antigens. Twenty five children with B-cell precursor ALL were prospectively enrolled into the study. The mononuclear cells from peripheral blood or bone marrow were cultured and stimulated (or not) with CD40L and IL-4. The assessment of costimulatory/adhesion molecules with the use of flow cytometry and real-time RT PCR were used to confirm the possibility of turning ALL cells into dendritic-like cells. Additionally 22 tumor associated antigens mRNA levels were determined by real-time PCR technique with the TaqMan chemistry using ready-to-use Low Density Arrays for Gene Expression. The results of the study showed maintained expression and even up-regulation of some (PNPT1, PMPCB, HMMR/RHAMM, BSG and ERCC1) tumor associated antigens in CD40-activated leukemic cells. CD40L stimulation leading to the differentiation of leukemic cells into DCs which combine both antigen presenting function and expression of tumor associated antigens represents an interesting approach in cancer immunotherapy.

B-cell chronic lymphocytic leukemia-derived dendritic cells stimulate allogeneic T-cell response and express chemokines involved in T-cell migration.

UNLABELLED: Despite discovery of new therapeutic agents, including nucleoside analogs and monoclonal antibodies, the B-cell chronic lymphocytic leukemia (B-CLL) remains incurable. In recent years, some effort has been made in developing T-cell specific immunity against neoplasmatic cells. Reconstitution of effective costimulation and immunological response of host T-cells against CLL cells could be a potential approach in immunotherapeutic trials. CD40/CD40L system is involved in the survival and proliferation of normal and neoplasmatic B-cells. Some preclinical studies have shown that CD40 stimulation can differentiate leukemic cells into dendritic cells (DCs) and result in host response. In this study, we sought to determine whether B-CLL cells could be turned into efficient and functional antigen presenting cells, as well as to assess the type of allogeneic T-cell response against B-CLL - derived DCs. MATERIAL AND METHODS: B-CLL cells from 25 patients were cultured with or without the presence of CD40L and IL-4 for 96 hours and then cultured in mixed lymphocyte reaction with allogeneic T-cells. RESULTS: 1) after CD40 stimulation B-CLL cells achieved phenotypical and functional characterization of DCs (i.e. upregulated co-stimulatory and adhesion molecules at mRNA and protein level) 2) leukemia-derived DCs expressed higher amount of mRNA for chemokines involved in T-cell migration (MDC, TARC and CCR7) 3) the proliferating response of Tcells against leukemia-derived DCs consisted of CD4 and CD8 cells (upregulation of HLA-DR and OX40). CONCLUSIONS: our experiment confirm that B-CLL cells can be turned into dendritic-like cells, additionally, these cells express chemokines involved in T-cell migration and stimulate allogeneic response.

Acute lymphoblastic leukaemia cells express CCR7 but not higher amounts of IL-10 after CD40 ligation.

OBJECTIVE: Production of cytokines that support T-cell activation and proliferation and migration to lymph nodes is one of the most important terms of cancer vaccine development. In previous studies we and others used CD40 ligation to obtain higher expression of co-stimulatory and adhesion molecules on leukaemic cells from children with acute lymphoblastic leukaemia (ALL). This time we assess the cytokine and chemokine gene expression profile in CD40-stimulated ALL cells. MATERIAL AND METHODS: Malignant cells from 25 children with BCP-ALL were stimulated (or not) with huCD40LT and rIL-4 for 96 h. Eleven different molecule, cytokine and chemokine mRNAs levels (CCR7, IL-23, TGF-beta-IP, IFN-gamma, IL-10, CD1a, CD40, CD54, CD80, CD83, CD86) were determined using the real-time PCR technique with TaqMan chemistry using ready-to-use low-density arrays for gene expression by Applied Biosystems. RESULTS: 1) Increases in mRNA levels for CD40, CD54 and CD80 after CD40L and IL-4 stimulation were observed, 2) CCR7 mRNA expression was higher after CD40 ligation than before the culture (p = 0.002), 3) IL-10 mRNA expression was higher after the culture with medium than before the culture (p = 0.01). CONCLUSIONS: The results show that leukaemia-derived dendritic cells obtained with CD40 ligation express CCR7 - chemokine is involved in migration to lymph nodes and does not produce higher amounts of IL-10, a potent immunosuppressive cytokine. Our preclinical findings could be used in the design of immunotherapy trials for the treatment of children with ALL.

Low expression of costimulatory molecules and mRNA for cytokines are important mechanisms of immunosuppression in acute lymphoblastic leukemia in children?

UNLABELLED: Mechanisms leading blasts of acute lymphoblastic leukemia to escape from immune surveillance are still unknown. Only few reports showed that ALL cells are inefficient antigen presenting cells. The aim of the study was to assess expression of critical costimulatory/adhesion molecules and mRNA for main pro- and anti-inflammatory cytokines in ALL cells. Children with B-cell precursor ALL (n=20) were prospectively enrolled into the study. Expression of costimulatory/adhesion molecules (CD1a, CD11c, CD40, CD54, CD80, CD83, CD86, CD123, HLA class I and II) was assessed by flow cytometry and mRNA for cytokines (IFN-gamma, IL-10, IL-4, TGF-beta) - with real-time PCR. RESULTS: 1) high expression was observed for HLA I and II class, moderate for CD40, CD83, CD86 and low or no expression for CD80, CD54, CD1a, CD11c and CD123; 2) we found expression of mRNA for IFN-gamma, IL-10, IL-4 and TGF-beta in blasts cells (but not in all specimens). We noted relatively lower expression of all assessed cytokines comparing to T-cells obtained from healthy donors but interestingly expression for IL-10 was higher in normal B-cells than in blast cells, and IFN-gamma and IL-4 were not found in normal B-cells. In summary we suggest that ALL-blasts present low expression of costimulatory/adhesion molecules and mRNA for cytokines and this probably contribute to the absence of host T- cells stimulation to immune response.