T cell deficiency

T cell deficiency
Human T Cell
SpecialtyImmunology
SymptomsEczematous
TypesPrimary or Secondary
Diagnostic methodDelayed hypersensitivity skin test, T cell count
TreatmentBone marrow transplant, Immunoglobulin replacement

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).[medical citation needed]

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.

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:

Types

Primary or secondary

Lymphoma

Complete or partial deficiency
Recognition of T cell deficiency
  • Recognition of T cell disorders can involve identifying deficiencies in MHC class I or class II molecules. MHC class I and MHC class II molecules are cell-surface proteins that facilitate immune recognition by displaying peptide antigens to T lymphocytes. MHC class I presents peptides derived from intracellular proteins to CD8⁺ cytotoxic T cells, while MHC class II presents peptides originating from extracellular sources to CD4⁺ helper T cells. This antigen presentation allows the immune system to distinguish normal cells from those that are infected or otherwise altered, enabling an appropriate and targeted immune response. A deficiency in MHC class I interferes with the maturation of cytotoxic T cells (CD8+), which rely on MHC I for proper development, leading to a deficiency of these cells. Without functional MHC I, CD8+ T cells cannot effectively destroy virus-infected or abnormal cells. Similarly, MHC class II deficiency disrupts helper T cell (CD4+) maturation, leading to T cell deficiency, impaired activation of other immune cells, and a weakened immune response.

Treatment

Harvested bone marrow in preparation for transplant

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

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.

See also

References

  1. 1 2 3 4 5 6 7 8 9 10 11 12 Medscape > T-cell Disorders Archived 2019-12-30 at the Wayback Machine. Author: Robert A Schwartz, MD, MPH; Chief Editor: Harumi Jyonouchi, MD. Updated: May 16, 2011
  2. 1 2 3 "Immunodeficiency (Primary and Secondary). Information". patient.info. Archived from the original on 2022-12-21. Retrieved 2017-05-18.
  3. 1 2 Fried, Ari J.; Bonilla, Francisco A. (2017-05-19). "Pathogenesis, Diagnosis, and Management of Primary Antibody Deficiencies and Infections". Clinical Microbiology Reviews. 22 (3): 396–414. doi:10.1128/CMR.00001-09. ISSN 0893-8512. PMC 2708392. PMID 19597006.
  4. 1 2 "T-cell count: MedlinePlus Medical Encyclopedia". medlineplus.gov. Archived from the original on 2019-12-01. Retrieved 2017-05-18.
  5. ↑ Alberts B, Johnson A, Lewis J, Raff M, Roberts k, Walter P (2002) Molecular Biology of the Cell Archived 2010-11-12 at the Wayback Machine . Garland Science: New York, NY pg 1367
  6. ↑ Cole, Theresa S.; Cant, Andrew J. (2010). "Clinical experience in T cell deficient patients". Allergy, Asthma & Clinical Immunology. 6 (1): 9. doi:10.1186/1710-1492-6-9. ISSN 1710-1492. PMC 2877019. PMID 20465788.
  7. ↑ Prasad, Paritosh (2013). Pocket Pediatrics: The Massachusetts General Hospital for Children Handbook of Pediatrics. Lippincott Williams & Wilkins. p. Google books gives no page. ISBN 978-1-4698-3009-4. Archived from the original on 7 April 2022. Retrieved 19 May 2017.
  8. 1 2 Page 435 Archived 2023-01-12 at the Wayback Machine in: Jones, Jane; Bannister, Barbara A.; Gillespie, Stephen H. (2006). Infection: Microbiology and Management. Wiley-Blackwell. ISBN 978-1-4051-2665-6.
  9. 1 2 3 4 5 6 7 8 9 10 11 12 Page 432 Archived 2023-01-12 at the Wayback Machine, Chapter 22, Table 22.1 in: Jones, Jane; Bannister, Barbara A.; Gillespie, Stephen H. (2006). Infection: Microbiology and Management. Wiley-Blackwell. ISBN 978-1-4051-2665-6.
  10. ↑ Ramalingam, TR; Vaidhyanathan, L; NK, HR; Uppuluri, R; Raj, R (2024). "Clinical, immunological, and molecular findings in two patients with MHC class I deficiency and post-transplant outcome". Pediatric Allergy and Immunology. 35 (7) 14196. doi:10.1111/pai.14196. PMID 38989814 – via EBSCO.
  11. 1 2 Villard, J; Lisowska-Grospierre, B; van der Elsen, P; Fischer, A; Reith, W; Mach, B (1997). "Mutation of RFXAP, a regulator of MHC class II genes, in primary MHC class II deficiency". The New England Journal of Medicine. 337 (11): 748–753. doi:10.1056/NEJM199709113371104. PMID 9287230 – via JSTOR.
  12. ↑ Ramalingam, TR; Vaidhyanathan, L; NK, HR; Uppuluri, R; Raj, R (2024). "Clinical, immunological, and molecular findings in two patients with MHC class I deficiency and post-transplant outcome". Pediatric Allergy and Immunology. 35 (7) 14196. doi:10.1111/pai.14196. PMID 38989814 – via EBSCO.
  13. ↑ "B-Cell and T-Cell Combined Disorders: Background, Pathophysiology, Epidemiology". 2018-12-11. Archived from the original on 2019-04-14. Retrieved 2017-05-19. {{cite journal}}: Cite journal requires |journal= (help)

Further reading