RESUMO
Children with Down syndrome (DS) are at an increased risk of developing transient abnormal myelopoiesis (TAM) and acute leukemia. Aberrant expression of CD56 has been observed on myeloid leukemic blasts in DS patients. In general, CD56 expression in acute myeloid leukemia (AML) is considered a promoter of leukemogenesis. We did a retrospective flow cytometric study to investigate mature myelomonocytic cell CD56 expression patterns in TAM, non-TAM, and leukemia cases with DS. Flow cytometric analysis showed that granulocyte and monocyte aberrant/dysplastic CD56 expression is an inherent characteristic of most DS patients irrespective of the presence of TAM or leukemia. Increased CD56 expression in monocyte and granulocyte populations in DS could be multifactorial; greater expression of RUNX1 secondary to the gene dose effect of trisomy 21 along with the maturational state of the cells are the potential contributors. Unlike AML seen in non-DS patients, CD56 overexpression in DS AML cases does not appear to play a role in leukemogenesis.
Assuntos
Antígeno CD56/biossíntese , Síndrome de Down/genética , Granulócitos/metabolismo , Monócitos/metabolismo , Mielopoese , Antígenos CD/análise , Antígeno CD56/genética , Transformação Celular Neoplásica , Pré-Escolar , Subunidade alfa 2 de Fator de Ligação ao Core/biossíntese , Subunidade alfa 2 de Fator de Ligação ao Core/genética , Síndrome de Down/metabolismo , Síndrome de Down/fisiopatologia , Citometria de Fluxo , Regulação da Expressão Gênica , Humanos , Lactente , Leucemia Mieloide , Leucocitose/etiologia , Estudos Retrospectivos , Trombocitopenia/etiologiaRESUMO
AIMS: To compare immunological microenvironments in local and distant lymphoid tissues in Hodgkin's lymphoma (HL) in children. METHODS: We have analysed diagnostic bone marrow (BM) samples in 22 and corresponding involved lymph node (LN) in eight and peripheral blood (PB) in eight cases of HL by flow cytometry and sought correlations with clinical features retrospectively. RESULTS: While there were significant differences in lymphocyte compositions of BM and LN tissues, the distribution of lymphocyte subsets mimicked each other in BM and PB. CD8-positive cytotoxic T cells predominate the bone marrow in contrast to CD4-positive helper T cells in LN tissue with corresponding CD4/CD8 ratios (0.85 and 5.3, respectively; p=0.002). Additionally, T-large granular lymphocytes population was much higher in BM in comparison to LN tissue (10.5% vs 4.5%; p=0.036). CONCLUSIONS: Local immunological microenvironment appears to be highly influenced by HL tumour cells and distant site lymphocyte composition reflects immune response to control the neoplastic process.
