Sandbox: T cell: Difference between revisions
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* Other routes of transmission for HTLV-1 may include sexual contact, exposure to contaminated blood, or vertical maternal transmission. | * 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 leukemia. | * There appears to be a long latent period between HTLV-1 infection and the development of adult T‐cell leukemia. | ||
* The oncogenesis of HTLV‐I infection, which results in the development of adult T-cell leukemia, is due to: | |||
:* HTLV-I basic leucine zipper factor | |||
:* HTLV-I p40 tax viral protein | |||
:* Activation of JAK/STAT signaling pathway by HTLV-I | |||
:* Enhancement of CREB by HTLV-I | |||
* The disease manifests in 75% of cases with leukemia and in the remaining as a pure lymphomatous form | * The disease manifests in 75% of cases with leukemia and in the remaining as a pure lymphomatous form |
Revision as of 14:30, 3 November 2015
Overview
Pathogenesis
- Adult T‐cell leukemia arises from post‐thymic lymphocytes, which are normally involved in the process of cell-mediated and humoral immune responses.
- Adult T‐cell leukemia is mainly caused by 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 leukemia.
- The oncogenesis of HTLV‐I infection, which results in the development of adult T-cell leukemia, is due to:
- HTLV-I basic leucine zipper factor
- HTLV-I p40 tax viral protein
- Activation of JAK/STAT signaling pathway by HTLV-I
- Enhancement of CREB by HTLV-I
- The disease manifests in 75% of cases with leukemia 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