Sorted By Test Name - Mayo Medical Laboratories

TCGR
83122
> or =55 years: >78 copies per million CD3 T cells
TREC results are expressed as copies per million CD3 T cells for adult specimens or per million
peripheral blood mononuclear cells for pediatric specimens.
Clinical References: 1. Douek DC, McFarland RD, Keiser PH, et al: Changes in thymic function
with age and during the treatment of HIV infection. Nature 1998;396:690-694 2. Hazenberg MD,
Verschuren MCM, Hamann D, et al: T cell receptor excision circles as markers for recent thymic
emigrants: basic aspects, technical approach, and guidelines for interpretation. J Mol Med
2001;79:631-640 3. Parkman R, Weinberg K: Immunological reconstitution following hematopoietic stem
cell transplantation. In Hematopoietic Cell Transplantation. 2nd edition. Edited by ED Thomas, KG
Blume, SJ Forman. Blackwell Scientific, Oxford, UK, 1999, pp 704-711 4. Weinberg K, Blazar BR,
Wagner JE, et al: Factors affecting thymic function after allogeneic hematopoietic stem cell
transplantation. Blood 2001;97:1458-1466 5. Weinberg K, Annett G, Kashyap A, et al: The effect of
thymic function on immunocompetence following bone marrow transplantation. Biol Blood Marrow
Transplant 1995;1:18-23 6. Auletta JJ, Lazarus HM: Immune restoration following hematopoietic stem
cell transplantation: an evolving target. Bone Marrow Transplant 2005;35:835-857 7. Borghans JA,
Bredius RG, Hazenberg MD, et al: Early determinants of long-term T cell reconstitution after
hematopoietic stem cell transplantation for severe combined immunodeficiency. Blood 2006;108:763-769
8. Douek DC, Vescio RA, Betts MR, et al: Assessment of thymic output in adults after hematopoietic
stem cell transplantation and prediction of T cell reconstitution. Lancet 2000;355:1875-1881 9. Jamieson
BD, Douek DC, Killian S, et al: Generation of functional thymocytes in the human adult. Immunity
1999;10:569-575 10. Carmichael KF, Abayomi A: Analysis of diurnal variation of lymphocyte subsets in
healthy subjects and its implication in HIV monitoring and treatment. 15th Intl Conference on AIDS,
Bangkok, Thailand, 2004, Abstract B11052 11. Dimitrov S, Benedict C, Heutling D, et al: Cortisol and
epinephrine control opposing circadian rhythms in T-cell subsets. Blood 2009 (prepublished online March
17, 2009) 12. Dimitrov S, Lange T, Nohroudi K, Born J: Number and function of circulating antigen
presenting cells regulated by sleep. Sleep 2007;30:401-411 13. Kronfol Z, Nair M, Zhang Q, et al:
Circadian immune measures in healthy volunteers: relationship to hypothalamic-pituitary-adrenal axis
hormones and sympathetic neurotransmitters. Psychosom Med 1997;59:42-50 14. Malone JL, Simms TE,
Gray GC, et al: Sources of variability in repeated T-helper lymphocyte counts from HIV 1-infected
patients: total lymphocyte count fluctuations and diurnal cycle are important. J AIDS 1990;3:144-151 15.
Paglieroni TG, Holland PV: Circannual variation in lymphocyte subsets, revisited. Transfusion
1994;34:512-516
T-Cell Receptor Gene Rearrangement, PCR, Blood
Clinical Information: The T-cell receptor (TCR) genes (alpha, beta, delta, and gamma) are
comprised of numerous, discontinuous coding segments that somatically rearrange to produce
heterodimeric cell surface T-cell receptors, either alpha/beta (90%-95% of T cells) or gamma/delta
(5%-10% of T cells). With rare exceptions (eg, some neoplastic B-lymphoid proliferations), other cell
types retain the "germline" configuration of the TCR genes without rearrangement. The marked diversity
of somatic TCR-gene rearrangements is important for normal immune functions, but also serves as a
valuable marker to distinguish abnormal T-cell proliferations from reactive processes. A monoclonal
expansion of a T-cell population will result in the predominance of a single TCR-gene rearrangement
pattern. In contrast, reactive T-cell expansions are polyclonal (or multiclonal), with no single clonotypic
population predominating in the population of T cells. These distributive differences in both TCR
sequence and genomic rearrangement fragment sizes can be detected by molecular techniques (ie, PCR)
and used to determine if a population of T cells shows monoclonal or polyclonal features.
Useful For: Determining whether a T-cell population is polyclonal or monoclonal
Interpretation: An interpretive report will be provided. Results will be characterized as positive,
negative, or indeterminate for a clonal T-cell population. In the appropriate clinicopathologic setting, a
monoclonal result is associated with a neoplastic proliferation of T cells (see Cautions).
Reference Values:
An interpretive report will be provided.
Positive, negative, or indeterminate for a clonal T-cell population
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