Sandbox: T cell: Difference between revisions
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==Overview== | ==Overview== | ||
==Pathogenesis== | ==Pathogenesis== | ||
* Adult T‐cell leukaemia | * Adult T‐cell leukaemia arises from post‐thymic lymphocytes, which are normally involved in the process of cell-mediated immunity. | ||
* | * Adult T‐cell leukaemia is linked to an infection with human T‐cell lymphotropic virus (HTLV‐I). | ||
* | * HTLV-1 is usually transmitted via breast feeding early in life. | ||
* | * Other routes of transmission for HTLV-1 may include sexual contact, exposure to contaminated blood, or vertical maternal transmission. | ||
* There appears to be a long latent period between HTLV-1 infection and the development of adult T‐cell leukaemia. | |||
* HTLV-I p40 tax viral protein: non structural protein that causes transcriptional activation of many genes in infected lymphocytes | * HTLV-I p40 tax viral protein: non structural protein that causes transcriptional activation of many genes in infected lymphocytes | ||
* Enhancement of c-AMP response element binding transcription factor (CREB) phosphorylation | * Enhancement of c-AMP response element binding transcription factor (CREB) phosphorylation | ||
Line 29: | Line 31: | ||
* antibodies to HTLV‐I are demonstrable | * antibodies to HTLV‐I are demonstrable | ||
* defects of cell-mediated immunity recurrent infections | * defects of cell-mediated immunity recurrent infections | ||
==Genetic== | ==Genetic== |
Revision as of 14:07, 3 November 2015
Overview
Pathogenesis
- Adult T‐cell leukaemia arises from post‐thymic lymphocytes, which are normally involved in the process of cell-mediated immunity.
- Adult T‐cell leukaemia is linked to an infection with human T‐cell lymphotropic virus (HTLV‐I).
- HTLV-1 is usually transmitted via breast feeding early in life.
- Other routes of transmission for HTLV-1 may include sexual contact, exposure to contaminated blood, or vertical maternal transmission.
- There appears to be a long latent period between HTLV-1 infection and the development of adult T‐cell leukaemia.
- HTLV-I p40 tax viral protein: non structural protein that causes transcriptional activation of many genes in infected lymphocytes
- Enhancement of c-AMP response element binding transcription factor (CREB) phosphorylation
- HTLV-I basic leucine zipper factor (HBZ): causes T cell proliferation and oncogenesis
- JAK/STAT pathway constitutively activated in HTLV-I infected cells
- The disease manifests in 75% of cases with leukaemia and in the remaining as a pure lymphomatous form
- widely disseminated disease which may involve liver, skin dermis layer, peripheral blood involvement , bone, and CNS
- anaemia and thrombocytopenia is variable
- patchy infiltrates Bone marrow infiltration
- Neutrophilia and eosinophilia Present
- Infiltration of the liver and spleen lead to the development of organomegally
- lytic bone lesions
- tumor-induced osteolysis hypercalcaemia
- increased osteoclastic activity
- elevated serum levels of IL-1, TGFβ, PTHrP, macrophage inflammatory protein (MIP-1α), and receptor activator of nuclear factor-κB ligand (RANKL) have been associated with hypercalcemia
- Diffuse infiltration of the lymph node leading expansion of the paracortical area
- Infiltration of the dermis skin infiltration, epidermotropism present and Pautrier's microabcesses
- antibodies to HTLV‐I are demonstrable
- defects of cell-mediated immunity recurrent infections
Genetic
- +3, +7, +21, monosomy X,deletion of chromosome Y and chromosomes 6 and 14q;
- 14q11 and break points e TCR‐alpha and ‐delta chain genes TCRA and TCRD
- 14q32 of TCL1
- mutations of tumour‐suppressor genes CDKN2A (p16), CDKN2B (p15) and TP53 (p53)
Gross
- Nodules skin
Micro
- pleomorphic, a medium size lymphocyte conndensed chromatin
- convoluted or polylobated nucleus
- nucleoli are not visibl
- cytoplasm agranular
- “flower cell”
- Reed-Sternberg like cells may also be present
- CD4 positive CD8 positive
- CD2 and CD5 positive
- CD7 negativ
- CD3 and T‐cell receptor (TCR)‐β may be down‐regulated
- CD2, CD3, CD4, CD5, CD25, TCR α/β, CD45ROCD56 expressionCCR4, FOXP3, HLA-DR, L-selectin (CD62), MUM-1