T cell deficiency

From Wikipedia, the free encyclopedia
Jump to: navigation, search

T cell deficiency is a deficiency of T cells, either caused by lymphocytopenia of T cells or by decreased function of individual T cells. It causes an immunodeficiency of cell-mediated immunity.

Classifications of causes[edit]

By complete versus partial deficiency[edit]

Complete insufficiency of T cell function can result from hereditary conditions (also called primary conditions) such as severe combined immunodeficiency (SCID), Omenn syndrome, and Cartilage-hair hypoplasia.[1]

Causes of partial insufficiencies of T cell function include acquired immune deficiency syndrome (AIDS), and hereditary conditions such as DiGeorge syndrome (DGS), chromosomal breakage syndromes (CBSs), and B-cell and T-cell combined disorders such as ataxia telangiectasia (AT) and Wiskott-Aldrich syndrome (WAS).[1]

Primary versus secondary[edit]

Primary (or hereditary) immunodeficiencies of T cells include some that cause complete insufficiency of T cells, such as severe combined immunodeficiency (SCID), Omenn syndrome, and Cartilage-hair hypoplasia.[1]

Secondary (or acquired) causes are mainly:[2]

Overall, secondary causes are more common than primary ones.[2]

Thymic versus peripheral[edit]

Causes of T cell deficiency by thymic hypoplasia can, in turn, be classified as:

Peripheral (or non-thymic) causes of T cell deficiency include: Purine nucleoside phosphorylase deficiency, hyper IgM syndrome (in turn including, for example, 1)

Effects[edit]

Pathogens of concern[edit]

Further information: Intracellular pathogen

The main pathogens of concern in T cell deficiencies are intracellular pathogens, including Herpes simplex virus, Mycobacterium and Listeria.[3] Also, intracellular fungal infections are also more common and severe in T cell deficiencies.[3]

Other intracellular pathogens of major concern in T cell deficiency are:

Presentations[edit]

Presentations differ among causes, but T cell insufficiency generally manifests as unusually severe common viral infections (e.g. by respiratory syncytial virus (RSV), enterovirus, rotavirus), mucocutaneous candidiasis, diarrhea, and eczematous or erythrodermatous rashes.[1] Failure to thrive and cachexia are late signs of a T-cell defect.[1]

References[edit]

  1. ^ a b c d e Medscape > T-cell Disorders. Author: Robert A Schwartz, MD, MPH; Chief Editor: Harumi Jyonouchi, MD. Updated: May 16, 2011
  2. ^ a b Page 432, Chapter 22, Table 22.1 in: Jones, Jane; Bannister, Barbara A.; Gillespie, Stephen H. (2006). Infection: Microbiology and Management. Wiley-Blackwell. ISBN 1-4051-2665-5. 
  3. ^ a b Page 435 in: Jones, Jane; Bannister, Barbara A.; Gillespie, Stephen H. (2006). Infection: Microbiology and Management. Wiley-Blackwell. ISBN 1-4051-2665-5. 
  4. ^ a b c d e f g h i j k Page 432, Chapter 22, Table 22.1 in: Jones, Jane; Bannister, Barbara A.; Gillespie, Stephen H. (2006). Infection: Microbiology and Management. Wiley-Blackwell. ISBN 1-4051-2665-5.