T-cell receptor excision circles (TRECs) are small circles of
DNA
Deoxyribonucleic acid (; DNA) is a polymer composed of two polynucleotide chains that coil around each other to form a double helix. The polymer carries genetic instructions for the development, functioning, growth and reproduction of al ...
created in
T-cell
T cells (also known as T lymphocytes) are an important part of the immune system and play a central role in the adaptive immune response. T cells can be distinguished from other lymphocytes by the presence of a T-cell receptor (TCR) on their ce ...
s during their passage through the
thymus
The thymus (: thymuses or thymi) is a specialized primary lymphoid organ of the immune system. Within the thymus, T cells mature. T cells are critical to the adaptive immune system, where the body adapts to specific foreign invaders. The thymus ...
as they rearrange their
TCR genes. Their presence indicates maturation of T cells;
TRECs are reduced in
SCID (severe combined immunodeficiency disease).
Signal joint T-cell receptor excision circles (sjTRECs) might be used as a way to test the age of the individual from a blood sample. The detection of sjTRECs can be further used as a diagnostic tool to monitor the thymic output (e.g., following hematopoietic stem cell transplantation or in cases of AIDS).
See also
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T cell receptor
The T-cell receptor (TCR) is a protein complex, located on the surface of T cells (also called T lymphocytes). They are responsible for recognizing fragments of antigen as peptides bound to major histocompatibility complex (MHC) molecules. ...
*
V(D)J recombination
V(D)J recombination (variable–diversity–joining rearrangement) is the mechanism of somatic recombination that occurs only in developing lymphocytes during the early stages of T and B cell maturation. It results in the highly diverse repertoire ...
References
T cells
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