Abstract

T cell deficiency is a deficiency of T cells, caused by decreased function of individual T cells, it causes an immunodeficiency of cell-mediated immunity. T cells normal function is to help with the human body's immunity, they are one of the two primary types of lymphocytes(the other being B cells).

Symptoms and signs

Presentations differ among causes, but T cell insufficiency generally manifests as unusually severe common viral infections (respiratory syncytial virus, rotavirus), diarrhea, and eczematous or erythrodermatous rashes. Failure to thrive and cachexia are later signs of a T-cell deficiency.

Mechanism

In terms of the "normal" mechanism of T cell we find that it is a type of white blood cell that has an important role in immunity, and is made from thymocytes One sees in the "partial" disorder of T cells that happen due to cell signaling defects, are usually caused by hypomorphic gene defects Generally, (micro)deletion of 22Q11.2 is the most often seen.

Mechanism | Pathogens of concern

The main pathogens of concern in T cell deficiencies are intracellular pathogens, including "Herpes simplex virus", "Mycobacterium" and "Listeria". Also, intracellular fungal infections are also more common and severe in T cell deficiencies. Other intracellular pathogens of major concern in T cell deficiency are:

Diagnosis

The diagnosis of T cell deficiency can be ascertained in those individuals with this condition via the following:

- Delayed hypersensitivity skin test

- T cell count

- Detection via culture(infection)

Diagnosis | Types

Complete or partial deficiency

- "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.

- "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).

- "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.

- "Secondary causes" are more common than primary ones. Secondary (or acquired) causes are mainly:

Treatment

In terms of the management of T cell deficiency for those individuals with this condition the following can be applied:

- Killed vaccines should be used(not "live vaccines" in T cell deficiency)

- Bone marrow transplant

- Immunoglobulin replacement

- Antiviral therapy

- Supplemental nutrition

Treatment | Epidemiology

In the U.S. this defect occurs in about 1 in 70,000, with the majority of cases presenting in early life.

Furthermore, SCID has an incidence of approximately 1 in 66,000 in California