A microRNA profile of human CD8(+) regulatory T cells and characterization of the effects of microRNAs on Treg cell-associated genes.

Recently, regulatory T (Treg) cells have gained interest in the fields of immunopathology, transplantation and oncoimmunology. Here, we investigated the microRNA expression profile of human natural CD8(+)CD25(+) Treg cells and the impact of microRNAs on molecules associated with immune regulation. We purified human natural CD8(+) Treg cells and assessed the expression of FOXP3 and CTLA-4 by flow cytometry. We have also tested the ex vivo suppressive capacity of these cells in mixed leukocyte reactions. Using TaqMan low-density arrays and microRNA qPCR for validation, we could identify a microRNA 'signature' for CD8(+)CD25(+)FOXP3(+)CTLA-4(+) natural Treg cells. We used the 'TargetScan' and 'miRBase' bioinformatics programs to identify potential target sites for these microRNAs in the 3'-UTR of important Treg cell-associated genes. The human CD8(+)CD25(+) natural Treg cell microRNA signature includes 10 differentially expressed microRNAs. We demonstrated an impact of this signature on Treg cell biology by showing specific regulation of FOXP3, CTLA-4 and GARP gene expression by microRNA using site-directed mutagenesis and a dual-luciferase reporter assay. Furthermore, we used microRNA transduction experiments to demonstrate that these microRNAs impacted their target genes in human primary Treg cells ex vivo. We are examining the biological relevance of this 'signature' by studying its impact on other important Treg cell-associated genes. These efforts could result in a better understanding of the regulation of Treg cell function and might reveal new targets for immunotherapy in immune disorders and cancer

Chronic Myelomonocytic Leukemia (cmml) - a Myelodysplastic Or Myeloproliferative Syndrome

Chronic myelomonocytic leukaemia (CMML), a disorder belonging to the group of myelodysplastic syndromes, has a number of peculiar features which raise the question as to whether it should be considered a distinct entity in its own right. The problems associated with its classification and diagnosis are discussed in this report using all currently available tools from clinical data to molecular genetics, including morphology, histology, cellular biology and cytogenetics. Three groups of patients can be identified (isolated monocytosis with a mild degree of dysplasia, severe cytopenia and the most frequent type with proliferative symptoms dominating the clinical picture). The latter group is close to atypical chronic myeloid leukaemia and perhaps these two entities should be regarded as a single one. Classification of the disease is further complicated by the possibility of evolution from one subgroup into another one and by the finding that CMML can also arise as a disorder secondary to other myeloproliferative (MPS) or myelodysplastic (MDS) syndromes. No specific marker of the disease has been identified by cytogenetics or molecular biology. Due to all these facts, we believe that CMML should perhaps be viewed more pragmatically by considering the use of prognostic factors that could at least help to define different groups of patients who may require different therapeutic strategies. We conclude that CMML is a heterogeneous syndrome with features of both MPS and MDS, encompassing primary and secondary stem cell disorders and varying widely in its clinical presentation. This heterogeneity should stimulate the search for reliable predictors of evolution which would allow a better definition of CMML subtypes based on prognostic factors

Chronic Myelomonocytic Leukemia - Single Entity Or Heterogeneous Disorder - a Prospective Multicenter Study of 100 Patients

To investigate the prognostic factors in chronic myelomonocytic leukemia (CMMoL), and to determine the importance of cytogenetic abnormalities at diagnosis and during evolution, a multicentric prospective study was established by the Groupe Francais de Cytogenetique Hematologique. One hundred patients were analyzed: 29 had cytogenetic abnormalities, among which the most frequent were +8, -Y, -7/7q-, and 12p-. Transformation into acute leukemia (AL) occurred in 26 patients. At transformation, eight patients had new cytogenetic abnormalities, not different from those described in the chronic phase of this disease. The median survival was 36 months (+/- 20 months, 95%, confidence interval). In multivariate analysis, four factors were associated with shorter survival: anemia < 10 g/dl, thrombocytopenia < 100 x 10(9)/L, splenomegaly, and the presence of immature precursors (IMP) in peripheral blood (PB). A very good prognosis subgroup could be identified which included eight patients with myelodysplasia and monocytosis only and none of the four unfavorable prognostic factors. This study confirmed the cytogenetic findings previously described by our group, and its results yielded further prognostic information. It also indicates the heterogeneity of this disease [some patients show clinical and biologic features of myeloproliferative syndromes (MDS, especially karyotypic abnormalities described only in these syndromes), whereas others appear more to have myelodysplasia, shifting from refractory anemia (RA) to CMMoL], and stresses the need for a more precise definition of this entity

Chronic myelomonocytic leukaemia (CMML)--a myelodysplastic or myeloproliferative syndrome?

Chronic myelomonocytic leukaemia (CMML), a disorder belonging to the group of myelodysplastic syndromes, has a number of peculiar features which raise the question as to whether it should be considered a distinct entity in its own right. The problems associated with its classification and diagnosis are discussed in this report using all currently available tools from clinical data to molecular genetics, including morphology, histology, cellular biology and cytogenetics. Three groups of patients can be identified (isolated monocytosis with a mild degree of dysplasia, severe cytopenia and the most frequent type with proliferative symptoms dominating the clinical picture). The latter group is close to atypical chronic myeloid leukaemia and perhaps these two entities should be regarded as a single one. Classification of the disease is further complicated by the possibility of evolution from one subgroup into another one and by the finding that CMML can also arise as a disorder secondary to other myeloproliferative (MPS) or myelodysplastic (MDS) syndromes. No specific marker of the disease has been identified by cytogenetics or molecular biology. Due to all these facts, we believe that CMML should perhaps be viewed more pragmatically by considering the use of prognostic factors that could at least help to define different groups of patients who may require different therapeutic strategies. We conclude that CMML is a heterogeneous syndrome with features of both MPS and MDS, encompassing primary and secondary stem cell disorders and varying widely in its clinical presentation. This heterogeneity should stimulate the search for reliable predictors of evolution which would allow a better definition of CMML subtypes based on prognostic factors

Chronic myelomonocytic leukaemia (CMML)--a myelodysplastic or myeloproliferative syndrome?

Chronic myelomonocytic leukaemia (CMML), a disorder belonging to the group of myelodysplastic syndromes, has a number of peculiar features which raise the question as to whether it should be considered a distinct entity in its own right. The problems associated with its classification and diagnosis are discussed in this report using all currently available tools from clinical data to molecular genetics, including morphology, histology, cellular biology and cytogenetics. Three groups of patients can be identified (isolated monocytosis with a mild degree of dysplasia, severe cytopenia and the most frequent type with proliferative symptoms dominating the clinical picture). The latter group is close to atypical chronic myeloid leukaemia and perhaps these two entities should be regarded as a single one. Classification of the disease is further complicated by the possibility of evolution from one subgroup into another one and by the finding that CMML can also arise as a disorder secondary to other myeloproliferative (MPS) or myelodysplastic (MDS) syndromes. No specific marker of the disease has been identified by cytogenetics or molecular biology. Due to all these facts, we believe that CMML should perhaps be viewed more pragmatically by considering the use of prognostic factors that could at least help to define different groups of patients who may require different therapeutic strategies. We conclude that CMML is a heterogeneous syndrome with features of both MPS and MDS, encompassing primary and secondary stem cell disorders and varying widely in its clinical presentation. This heterogeneity should stimulate the search for reliable predictors of evolution which would allow a better definition of CMML subtypes based on prognostic factors