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Test Code TREGS T-Cell Subsets, Regulatory (Tregs)

Performing Laboratory

Mayo Medical Laboratories in Rochester

Reporting Name

T Cell Subsets, Regulatory (Tregs)

Specimen Type

Whole Blood EDTA


Specimen Required


Specimens are required to be received in the laboratory weekdays and by 4 p.m. on Friday. It is recommended that specimens arrive within 24 hours of draw. Specimens arriving on the weekend may be canceled. Draw and package specimen as close to shipping time as possible.

 

Container/Tube: Lavender top (EDTA)

Specimen Volume: 3 mL

Collection Instructions: Send specimen in original tube. Do not aliquot.

Additional Information:

1. Ordering physician's name and phone number are required.

2. For serial monitoring, we recommend that specimen draws be performed at the same time of day.


Reject Due To

Hemolysis

Mild OK; Gross reject

Lipemia

Mild OK; Gross reject

Icterus

NA

Other

NA

Specimen Stability Information

Specimen Type Temperature Time
Whole Blood EDTA Ambient 72 hours

Specimen Minimum Volume

1 mL

Day(s) and Time(s) Performed

Monday through Friday

Do not send specimen after Thursday. Specimen must be received by 10 a.m. on Friday.

Specimen Retention Time

4 days

Analytic Time

3 days

Reference Values

The appropriate age-related reference values will be provided on the report.

Useful For

Evaluating patients with clinical features of IPEX (immune dysregulation, polyendocrinopathy, enteropathy, X-linked inheritance) and other primary immunodeficiencies, autoimmune diseases, allergy and asthma, and graft-vs-host disease post-hematopoietic stem cell transplantation

Method Name

Flow Cytometry

Test Classification

This test was developed using an analyte specific reagent. Its performance characteristics were determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the U.S. Food and Drug Administration.

CPT Code Information

86359-T cells, total count

86361-Absolute CD4 count

LOINC Code Information

Test ID Test Order Name Order LOINC Value
TREGS T Cell Subsets, Regulatory (Tregs) In Process

 

Result ID Test Result Name Result LOINC Value
29143 % Activated CD4+ T cells (4+CD25+) 13332-2
29144 % Natural Tregs 89320-6
29145 % N. Naive Tregs 89319-8
29146 % CD4+CD25-CD127+ (Tr1/Th3) 89318-0
29147 Activated CD4+ T cells (4+CD25+) 26982-9
29148 CD4+CD25+CD127loCD45RO+ (Nat Tregs) 89316-4
29149 CD4+CD25+CD127loCD45RA+ Naive Tregs 89315-6
29150 CD4+CD25-CD127+ (Tr1/Th3) 89317-2
29177 Interpretation 69052-9

Clinical Information

Regulatory T cells (Tregs) are a population of CD4+ T cells with a unique role in the immune response. Tregs are crucial in suppressing aberrant pathological immune responses in autoimmune diseases, transplantation, and graft-vs-host disease after allogeneic hematopoietic stem cell transplantation.(1) Tregs are activated through the specific T-cell receptor, but their effector function is nonspecific and they regulate the local inflammatory response through cell-to-cell contact and cytokine secretion.(2) Tregs secrete interleukin (IL)-9 (IL-9), IL-10, and transforming growth factor-beta 1 (TGF-beta 1), which aid in the mediation of immunosuppressive activity.

 

Chief characteristics of the Treg population are surface expression of the CD25 protein (IL-2Ra) and the intracellular presence of the transcription factor Foxp3. The IL-7 receptor (CD127) is downregulated on Foxp3+CD4+CD25+ T cells and provides an excellent alternative cell-surface marker to Foxp3 for detecting natural Tregs (CD4+CD25+CD127lo).(2)

 

Natural Tregs account for 5% to 10% of the total CD4 T-cell population and are derived from thymic precursors.(3) Since CD25 is also expressed on activated T cells, the concomitant use of CD127 permits the differentiation of Tregs from activated T cells.(4) Natural Tregs express the memory marker CD45RO and have limited ability to proliferate. However, within the CD4+CD25+Treg population, there is a subset of Tregs that express the CD45 isoform generally associated with naive T cells (CD45RA), and this subset has been called natural naive (Nn) Tregs. Nn Tregs are most prominent in young adults and decrease with age along with the rest of the naive CD4 T-cell population.(5) Like other naive T cells, Nn Tregs have high proliferative capacity, as well as the suppressor activity of other Treg subsets. Present evidence suggests that Nn Tregs also have a thymic ancestry and are the precursors of the natural Tregs (that are of the memory, antigen-experienced phenotype) and appear to be composed of T cells with self-reactive T-cell receptors.(5)

 

Other subsets of Tregs include the Th3 cells, which secrete high levels of TGF-beta 1 and can be induced by oral administration of antigen, and regulatory T class 1 (Tr1) cells, which secrete interferon-gamma and IL-10.(5) These Treg subsets are most likely induced in the periphery and are responsible for peripheral tolerance to self antigens. The suppressive activity of Th3 and Tr1 cells are related to the cytokines they produce, TGF-beta 1 and IL-10, respectively.

 

The absence of Tregs as a result of mutations in the FOXP3 gene cause a primary immunodeficiency called IPEX (immune dysregulation, polyendocrinopathy, enteropathy, X-linked inheritance).(6) Patients with IPEX have a complex manifestation of symptoms including severe watery diarrhea due to significant villous atrophy and lymphocytic infiltration of bowel mucosa, early-onset autoimmune endocrinopathies involving the pancreas or thyroid, and a dermatitic (eczematous) rash. In addition, there are other autoimmune manifestations including autoimmune cytopenias and autoimmune hepatitis. Renal disease is quite common in these patients. Finally, these patients also have a significant predisposition to infections including sepsis, pneumonia, meningitis, and osteomyelitis.(6) Decreased Foxp3+CD4+CD25+Tregs have been reported in 1 patient with a STAT5b mutation.(7)

 

There is an expansion of Nn Tregs in patients with monoclonal gammopathy of undetermined significance and multiple myeloma, likely as a response to the process of malignant transformation.(8) Expansion of Tregs has also been reported in other neoplasias including B-cell chronic lymphocytic leukemia, Hodgkin disease, and solid tumors.

 

The absolute counts of lymphocyte subsets are known to be influenced by a variety of biological factors, including hormones, the environment, and temperature. The studies on diurnal (circadian) variation in lymphocyte counts have demonstrated progressive increase in CD4 T-cell count throughout the day, while CD8 T cells and CD19+ B cells increase between 8:30 am and noon, with no change between noon and afternoon. Natural killer cell counts, on the other hand, are constant throughout the day.(9) Circadian variations in circulating T-cell counts have been shown to be negatively correlated with plasma cortisol concentration.(10-12) In fact, cortisol and catecholamine concentrations control distribution and, therefore, numbers of naive versus effector CD4 and CD8 T cells.(10) It is generally accepted that lower CD4 T-cell counts are seen in the morning compared with the evening,(13) and during summer compared to winter.(14) These data, therefore, indicate that timing and consistency in timing of blood collection is critical when serially monitoring patients for lymphocyte subsets.

Interpretation

The lack of regulatory T (Treg) cells is associated with mutations in the FOXP3 gene. Low Tregs are also seen in the context of STAT5b mutations. Reduced Nn Tregs and natural Tregs are likely to predispose to autoimmunity, while reductions in Th3/Tr1 cells may impair oral and peripheral tolerance, also facilitating the development of autoimmunity.

 

The presence of expanded naive Tregs may indicate a process of malignant transformation, if other clinical features of malignant disease are present.

 

Increased Tregs in donor stem cell allografts have been associated with a reduced incidence of graft-versus-host disease (ie, mediating a protective effect) after allogeneic stem cell transplantation.

Cautions

This panel provides only quantitative information regarding the various regulatory T cell (Treg) subsets; it does not provide information on the functional aspect of these populations.

 

Results should be correlated with clinical presentation.

 

Molecular testing is required to confirm a diagnosis of IPEX (immune dysregulation, polyendocrinopathy, enteropathy, X-linked inheritance). Contact Mayo Medical Laboratories at 800-533-1710 for assistance in ordering molecular testing.

 

Treg cells may be reduced in a variety of clinical contexts such as in autoimmune diseases or allograft rejection.

 

Timing and consistency in timing of blood collection is critical when serially monitoring patients for lymphocyte subsets. See data under Clinical Information.

Clinical Reference

1. Sakaguchi S, Sakaguchi N, Shimizu J, et al: Immunologic tolerance maintained by CD25+CD4+ regulatory T-cells: their common role in controlling autoimmunity, tumor immunity, and transplantation tolerance. Immunol Rev 2001;182:18-32

2. Liu W, Putnam A, Xu-yu Z, et al: CD127 expression inversely correlates with FOXP3 and suppressive function of human CD4+ Treg cells. J Exp Med 2006;203(7):1701-1711

3. Seddiki N, Santner-Nanan B, Tangye SG, et al: Persistence of naive CD45RA+ regulatory T-cells in adult life. Blood 2006;107:2830-2838

4. Seddiki N, Santner-Nanan B, Martinson J, et al: Expression of IL-2 and IL-7 receptors discriminates between human regulatory and activated T-cells. J Exp Med 2006;203(7):1693-1700

5. Valmori D, Merlo A, Souleimanian NE, et al: A peripheral circulating compartment of natural naive CD4+Tregs. J Clin Invest 2005;115(7):1953-1962

6. Torgerson TR, Ochs HD: IPEX: FOXP3 mutations and lack of regulatory T-cells. J Allergy Clin Immunol 2007;120:744-750

7. Cohen AC, Nadeau KC, Tu W, et al: Decreased accumulation and regulatory function of CD4+CD25 (high) T-cells in human STAT5b deficiency. J Immunol 2006;177:2770-2774

8. Beyer M, Kochanek M, Giese T, et al: In vivo peripheral expansion of naive CD4+CD25(high) FOXP3+ regulatory T-cells in patients with multiple myeloma. Blood 2006;107:3940-3949

9. 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

10. Dimitrov S, Benedict C, Heutling D, et al: Cortisol and epinephrine control opposing circadian rhythms in T-cell subsets. Blood 2009;113(21):5134-5143

11. Dimitrov S, Lange T, Nohroudi K, Born J: Number and function of circulating antigen presenting cells regulated by sleep. Sleep 2007;30:401-411

12. 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

13. 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

14. Paglieroni TG, Holland PV: Circannual variation in lymphocyte subsets, revisited. Transfusion 1994;34:512-516

Method Description

EDTA anticoagulated blood is incubated with antibodies to various T-cell markers (ie, CD4, CD127, CD45RO, CD45RA, and CD25). After RBC lysis, the sample is washed to remove any unbound antibodies prior to analysis on a BD FACS CantoA (6-color) flow cytometry instrument. The assay uses 2 antibody tubes for data acquisition, but analysis is performed as a single panel. Each Treg subset is expressed as a percentage of total CD4+ T cells. BD Tru Count tubes are used to calculate the absolute count of cells per mcL for each subset. The regulatory T-cell panel is linked to the TCD4 test (TCD4/84348 CD4 Count for Immune Monitoring, Blood) within the experiment and, therefore, the CD3, CD4, and CD8 T-cell reference ranges are provided within the TCD4 assay. The regulatory T cell results are interpreted using a reference range derived from data of normal healthy adult and pediatric donors. Isotype controls are used in each assay to measure background fluorescence of the samples. A normal, healthy control is also included in each experiment to ensure the optimal performance of the assay.(Unpublished Mayo information)