CD4 & CD8 - Revision history

John at 18:45, 11 May 2023

2023-05-11T18:45:18Z

← Older revision		Revision as of 20:45, 11 May 2023
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	:<span style="color:navy">'''Diagnostic Use'''</span>		:<span style="color:navy">'''Diagnostic Use'''</span>


	'''CD4/CD8 in health'''		'''CD4/CD8 in health'''

John at 18:44, 11 May 2023

2023-05-11T18:44:53Z

← Older revision		Revision as of 20:44, 11 May 2023
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	(2) Absolute counts: These may be more informative than CD4/CD8 ratios: The normal CD4 count should be greater than 400/μL (reference range 500-1,500); CD8 lymphocyte counts should lie in the range to 200-800/μL		(2) Absolute counts: These may be more informative than CD4/CD8 ratios: The normal CD4 count should be greater than 400/μL (reference range 500-1,500); CD8 lymphocyte counts should lie in the range to 200-800/μL

	CD4/CD8 in mature T cell neoplasia
			'''CD4/CD8 in mature T cell neoplasia'''

	(1) CD4 proliferations particularly characterise cutaneous lymphomas and T-PLL (although T-PLL may express both CD4 and CD8, or less commonly only CD8)		(1) CD4 proliferations particularly characterise cutaneous lymphomas and T-PLL (although T-PLL may express both CD4 and CD8, or less commonly only CD8)

	(2) CD8 proliferation typifies ATLL (although simultaneous CD4 expression may occur) and T-LGL		(2) CD8 proliferation typifies ATLL (although simultaneous CD4 expression may occur) and T-LGL


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John at 18:44, 11 May 2023

2023-05-11T18:44:00Z

← Older revision		Revision as of 20:44, 11 May 2023
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	:<span style="color:navy">'''Diagnostic Use'''</span>		:<span style="color:navy">'''Diagnostic Use'''</span>

	CD4/CD8 in health		'''CD4/CD8 in health'''
	(1) CD4/CD8 ratio~~: for~~ healthy individuals the ratio in blood lies between 1.5 and 2.5. An inverted ratio is considered an “immune risk” phenotype (occurring in just less than 10% of 20- to 59-year-olds but increasing with age). However, there be quite wide variation depending on a range of factors ~~including~~ infection ~~with~~ the HIV virus.
			(1) CD4/CD8 ratio. For healthy individuals the ratio in blood lies between 1.5 and 2.5. An inverted ratio is considered an “immune risk” phenotype (occurring in just less than 10% of 20- to 59-year-olds but increasing with age). However, there can be quite wide variation in this ratio depending on a range of factors that include infection (that include the HIV virus). Ratios must be interpreted in clinical context and absolute counts are preferred in many circumstances,

	(2) Absolute counts: These may be more informative than CD4/CD8 ratios: The normal CD4 count should be greater than 400/μL (reference range 500-1,500); CD8 lymphocyte counts should lie in the range to 200-800/μL		(2) Absolute counts: These may be more informative than CD4/CD8 ratios: The normal CD4 count should be greater than 400/μL (reference range 500-1,500); CD8 lymphocyte counts should lie in the range to 200-800/μL

	CD4/CD8 in mature T cell neoplasia		CD4/CD8 in mature T cell neoplasia
	(1) CD4 proliferations particularly characterise cutaneous lymphomas and T-PLL (although T-PLL may express both CD4 and CD8, or ~~rarely~~ only CD8)		(1) CD4 proliferations particularly characterise cutaneous lymphomas and T-PLL (although T-PLL may express both CD4 and CD8, or less commonly only CD8)
	(2) CD8 proliferation typifies ATLL (although simultaneous CD4 expression may occur) and T-LGL		(2) CD8 proliferation typifies ATLL (although simultaneous CD4 expression may occur) and T-LGL


			----

John at 18:40, 11 May 2023

2023-05-11T18:40:12Z

← Older revision		Revision as of 20:40, 11 May 2023
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	CD4 and CD8 are transmembrane-proteins that amplify signal generation by the T cell receptor. During their initial development T cells acquire simultaneous expression of both CD4 and CD8, however when the mature T cells they express only CD4 or CD8.		CD4 and CD8 are transmembrane-proteins that amplify signal generation by the T cell receptor. During their initial development T cells acquire simultaneous expression of both CD4 and CD8, however when the mature T cells they express only CD4 or CD8:

	*CD4 is linked to T-helper cell function~~, interacting~~ with MHC class II (expressed for example on dendritic cells or B lymphocytes), but is also expressed by immune-presenting cells including monocytes, macrophages, and dendritic cells.		*'''CD4''' is linked to T-helper cell function. It interacts with MHC class II (expressed for example on dendritic cells or B lymphocytes), but is also expressed by immune-presenting cells including monocytes, macrophages, and dendritic cells.

			*'''CD8''' is particularly expressed by cytotoxic cells. It interacts with MHC class I (expressed on all nucleated cells) and is also expressed by natural killer cells and dendritic cells.

	*CD8 is particularly expressed by cytotoxic cells and interacts with MHC class I (expressed on all nucleated cells) and is also expressed by natural killer cells and dendritic cells.

John at 18:38, 11 May 2023

2023-05-11T18:38:29Z

← Older revision		Revision as of 20:38, 11 May 2023
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	~~Function~~		:<span style="color:navy">'''Background'''</span>
	CD4 and CD8 are transmembrane-~~glycoproteins~~ that amplify signal generation by the T cell receptor. T cells acquire simultaneous expression of both CD4 and CD8 ~~during their early the thymic stage of development~~, however when the mature T cells ~~enter the circulation~~ they express ~~either~~ CD4 or CD8 ~~only~~. CD4 is linked to T-helper cell function, interacting with MHC class II (expressed for example on dendritic cells or B lymphocytes), but is also expressed by immune-presenting cells including monocytes, macrophages, and dendritic cells. CD8 is particularly expressed by cytotoxic cells and interacts with MHC class I (expressed on all nucleated cells) and is also expressed by natural killer cells and dendritic cells.

			CD4 and CD8 are transmembrane-proteins that amplify signal generation by the T cell receptor. During their initial development T cells acquire simultaneous expression of both CD4 and CD8, however when the mature T cells they express only CD4 or CD8.

			*CD4 is linked to T-helper cell function, interacting with MHC class II (expressed for example on dendritic cells or B lymphocytes), but is also expressed by immune-presenting cells including monocytes, macrophages, and dendritic cells.

			*CD8 is particularly expressed by cytotoxic cells and interacts with MHC class I (expressed on all nucleated cells) and is also expressed by natural killer cells and dendritic cells.


			:<span style="color:navy">'''Diagnostic Use'''</span>

	CD4/CD8 in health		CD4/CD8 in health

John at 18:35, 11 May 2023

2023-05-11T18:35:12Z

← Older revision		Revision as of 20:35, 11 May 2023
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	:'''Systemic disease:''' On T lymphocytes these two co-stimulatory molecules define different functional types; an altered ratio between CD4 and CD8 cells can indicate systemic disease or immune dysfunction		:'''Systemic disease:''' On T lymphocytes these two co-stimulatory molecules define different functional types of T lymphocyte; consequemtly an altered ratio between CD4 and CD8 cells can indicate systemic disease or immune dysfunction
	:'''Neoplasia:''' Expanded populations of CD4 or CD8 cells (or T cells with unusual expression patterns of ~~these~~ molecules) may represent a malignant clone~~, and the~~ CD4 or CD8 expression may help identify the disease subtype. ~~However, restricted~~ CD4 or CD8 ~~expression cannot substitute for~~ molecular clonality analysis.		:'''Neoplasia:''' Expanded populations of CD4 or CD8 cells (or T cells with unusual expression patterns of both molecules) may represent a malignant clone. The suntype of CD4 or CD8 expression may help identify the disease subtype. Restricted expression of CD4 or CD8 is not the same as molecular clonality which should be confirmed by molecular analysis.

John: Created page with "
:'''Systemic disease:''' On T lymphocytes these two co-stimulatory molecules define different functional types; an altered ratio between CD4 and CD8 cells can indicate systemic disease or immune dysfunction :'''Neoplasia:''' Expanded populations of CD4 or CD8 cells (or T cells with unusual expression patterns of these molecules) may represent a malignant clone, and the CD4..."

2023-05-11T18:32:54Z

Created page with " <div style="background-color: #E0EEEE; {{round corners}} padding: 2em 2em; margin-right: 5px;"> :'''Systemic disease:''' On T lymphocytes these two co-stimulatory molecules define different functional types; an altered ratio between CD4 and CD8 cells can indicate systemic disease or immune dysfunction :'''Neoplasia:''' Expanded populations of CD4 or CD8 cells (or T cells with unusual expression patterns of these molecules) may represent a malignant clone, and the CD4..."

New page

<div style="background-color: #E0EEEE; {{round corners}} padding: 2em 2em; margin-right: 5px;">

:'''Systemic disease:''' On T lymphocytes these two co-stimulatory molecules define different functional types; an altered ratio between CD4 and CD8 cells can indicate systemic disease or immune dysfunction
:'''Neoplasia:''' Expanded populations of CD4 or CD8 cells (or T cells with unusual expression patterns of these molecules) may represent a malignant clone, and the CD4 or CD8 expression may help identify the disease subtype. However, restricted CD4 or CD8 expression cannot substitute for molecular clonality analysis.

</div>

Function
CD4 and CD8 are transmembrane-glycoproteins that amplify signal generation by the T cell receptor. T cells acquire simultaneous expression of both CD4 and CD8 during their early the thymic stage of development, however when the mature T cells enter the circulation they express either CD4 or CD8 only. CD4 is linked to T-helper cell function, interacting with MHC class II (expressed for example on dendritic cells or B lymphocytes), but is also expressed by immune-presenting cells including monocytes, macrophages, and dendritic cells. CD8 is particularly expressed by cytotoxic cells and interacts with MHC class I (expressed on all nucleated cells) and is also expressed by natural killer cells and dendritic cells.

CD4/CD8 in health
(1) CD4/CD8 ratio: for healthy individuals the ratio in blood lies between 1.5 and 2.5. An inverted ratio is considered an “immune risk” phenotype (occurring in just less than 10% of 20- to 59-year-olds but increasing with age). However, there be quite wide variation depending on a range of factors including infection with the HIV virus.
(2) Absolute counts: These may be more informative than CD4/CD8 ratios: The normal CD4 count should be greater than 400/μL (reference range 500-1,500); CD8 lymphocyte counts should lie in the range to 200-800/μL

CD4/CD8 in mature T cell neoplasia
(1) CD4 proliferations particularly characterise cutaneous lymphomas and T-PLL (although T-PLL may express both CD4 and CD8, or rarely only CD8)
(2) CD8 proliferation typifies ATLL (although simultaneous CD4 expression may occur) and T-LGL