A reliable and simplified sj/beta-TREC ratio quantification method for human thymic output measurement

J Immunol Methods. 2010 Jan 31;352(1-2):111-7. doi: 10.1016/j.jim.2009.11.007. Epub 2009 Nov 15.


Current techniques to peripherally assess thymic function are: the signal-joint T-cell receptor excision circle (sj-TREC) level measurement and the naive T cell and CD31+ TREC-rich subset determination. However, all of them are indirect approaches and none could be considered a direct recent thymic emigrant (RTE) marker. To overcome their limitations, Dion et al. (2004) described the sj/beta-TREC ratio that allows the peripheral quantification of the double negative to double positive intrathymic proliferation step. Nevertheless, the protocol described is expensive, sample and time-consuming, thus, limiting its usefulness. In this study, we describe a simplified protocol that reduces from 33 to 9 the amount of PCR reaction needed but maintaining the sensitivity and reproducibility of the original technique. In addition, we corroborated the effectiveness of our technique as an accurate thymic output-related marker by correlating the peripheral sj/beta-TREC ratio with a direct measurement of thymic function as the percentage of double positive thymocytes (r=0.601, p<0.001).

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antigens, CD / biosynthesis
  • Antigens, Differentiation / genetics
  • Antigens, Differentiation / immunology*
  • Cell Differentiation
  • Cell Proliferation
  • Female
  • Fetal Blood / cytology
  • Gene Rearrangement / genetics
  • Gene Rearrangement / immunology*
  • Humans
  • Polymerase Chain Reaction*
  • Receptors, Antigen, T-Cell / genetics
  • Receptors, Antigen, T-Cell / immunology
  • Receptors, Antigen, T-Cell / metabolism*
  • Reproducibility of Results
  • Thymus Gland / cytology
  • Thymus Gland / growth & development
  • Thymus Gland / immunology
  • Thymus Gland / metabolism*


  • Antigens, CD
  • Antigens, Differentiation
  • Receptors, Antigen, T-Cell