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. 2020 Jul 16:11:1411.
doi: 10.3389/fimmu.2020.01411. eCollection 2020.

Establishing Simultaneous T Cell Receptor Excision Circles (TREC) and K-Deleting Recombination Excision Circles (KREC) Quantification Assays and Laboratory Reference Intervals in Healthy Individuals of Different Age Groups in Hong Kong

Janette S Y Kwok  1 , Stephen K F Cheung  1 , Jenny C Y Ho  1 , Ivan W H Tang  1 , Patrick W K Chu  1 , Eric Y S Leung  1 , Pamela P W Lee  2 , Daniel K L Cheuk  2 , Vincent Lee  3 , Patrick Ip  2 , Y L Lau  2
Affiliations

Establishing Simultaneous T Cell Receptor Excision Circles (TREC) and K-Deleting Recombination Excision Circles (KREC) Quantification Assays and Laboratory Reference Intervals in Healthy Individuals of Different Age Groups in Hong Kong

Janette S Y Kwok et al. Front Immunol. .

Abstract

The clinical experience gathered throughout the years has raised awareness of primary immunodeficiency diseases (PIDD). T cell receptor excision circles (TREC) and kappa-deleting recombination excision circles (KREC) assays for thymic and bone marrow outputs measurement have been widely implemented in newborn screening (NBS) programs for Severe Combined Immunodeficiency. The potential applications of combined TREC and KREC assay in PIDD diagnosis and immune reconstitution monitoring in non-neonatal patients have been suggested. Given that ethnicity, gender, and age can contribute to variations in immunity, defining the reference intervals of TREC and KREC levels in the local population is crucial for setting up cut-offs for PIDD diagnosis. In this retrospective study, 479 healthy Chinese sibling donors (240 males and 239 females; age range: 1 month-74 years) from Hong Kong were tested for TREC and KREC levels using a simultaneous quantitative real-time PCR assay. Age-specific 5th-95th percentile reference intervals of TREC and KREC levels (expressed in copies per μL blood and copies per 106 cells) were established in both pediatric and adult age groups. Significant inverse correlations between age and both TREC and KREC levels were observed in the pediatric age group. A significant higher KREC level was observed in females than males after 9-12 years of age but not for TREC. Low TREC or KREC levels were detected in patients diagnosed with mild or severe PIDD. This assay with the established local reference intervals would allow accurate diagnosis of PIDD, and potentially monitoring immune reconstitution following haematopoietic stem cell transplantation or highly active anti-retroviral therapy in the future.

Keywords: K-deleting recombination excision circles; T cell receptor excision circles; immune reconstitution; primary immunodeficiency; reference interval.

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Figures

Figure 1
Figure 1
Dot Plot showing TREC copies/μL blood (A) and TREC copies/106 cells (B) among the study age groups. Blue full circles represent healthy males and red empty circles represent healthy females. A significant inverse correlation was observed between TREC levels and both pediatric and adult age groups (Pediatric: r = −0.6488, p < 0.0001 for copies/μL and r = −0.5487, p < 0.0001 for copies/106 cells; Adult: r = −0.4924, p < 0.0001 for copies/μL and r = −0.6289, p < 0.0001 for copies/106 cells).
Figure 2
Figure 2
Dot Plot showing KREC copies/μL blood (A) and TREC copies/106 cells (B) among the study age groups. Blue full circles represent healthy males and red empty circles represent healthy females. A significant inverse correlation was observed between KREC levels and pediatric age groups (Pediatric: r = −0.6577, p < 0.0001 for copies/μL and r = −0.6241, p < 0.0001 for copies/106 cells; Adult: r = 0.0903, p = 0.2216 for copies/μL and r = −0.0171, p = 0.8176 for copies/106 cells).
Figure 3
Figure 3
Trend of TREC copies/μL blood (A) and KREC copies/μL blood (B) among the study age groups. Data is expressed as median ± range. Blue full circles represent healthy males and red empty circles represent healthy females. A significant higher KREC level was observed for age groups after 9–12 years, except for 51–60 years. *p < 0.05, **p < 0.01, #p = 0.0510.
Figure 4
Figure 4
Dot Plot showing the correlations between copies/μL blood and copies/106 cells for TREC (A) and KREC (B) levels. Blue full circles represent healthy pediatric individuals and red empty circles represent healthy adults. A significant positive correlation was observed between both units for TREC and KREC levels (TREC level: r = 0.8319, p < 0.0001; KREC level: r = 0.7794, p < 0.0001).
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References

    1. Jung D, Alt FW. Unraveling V(D)J recombination; insights into gene regulation. Cell. (2004) 116:299–311. 10.1016/S0092-8674(04)00039-X - DOI - PubMed
    1. Livak F, Schatz DG. Identification of V(D)J recombination coding end intermediates in normal thymocytes. J Mol Biol. (1997) 267:1–9. 10.1006/jmbi.1996.0834 - DOI - PubMed
    1. Takeshita S, Toda M, Yamagishi H. Excision products of the T cell receptor gene support a progressive rearrangement model of the alpha/delta locus. EMBO J. (1989) 8:3261–70. 10.1002/j.1460-2075.1989.tb08486.x - DOI - PMC - PubMed
    1. Ye P, Kirschner DE. Reevaluation of T cell receptor excision circles as a measure of human recent thymic emigrants. J Immunol. (2002) 168:4968–79. 10.4049/jimmunol.168.10.4968 - DOI - PubMed
    1. Hazenberg MD, Verschuren MC, Hamann D, Miedema F, van Dongen JJ. T cell receptor excision circles as markers for recent thymic emigrants: basic aspects, technical approach, and guidelines for interpretation. J Mol Med. (2001) 79:631–40. 10.1007/s001090100271 - DOI - PubMed

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