title: A reliable and simplified sj/beta-TREC ratio quantification method for human thymic output measurement.
abstract: 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).
authors.affiliation: Laboratory of Immunovirology, Biomedicine Institute of Seville, Service of Infectious Diseases, Virgen del Rocio University Hospital, Avda. Manuel Siurot s/n 41013 Seville, Spain.
authors.forename: Sara
authors.initials: S
authors.lastname: Ferrando-Martínez
authors.forename: Jaime M
authors.initials: JM
authors.lastname: Franco
authors.forename: Ezequiel
authors.initials: E
authors.lastname: Ruiz-Mateos
authors.forename: Ana
authors.initials: A
authors.lastname: Hernández
authors.forename: Antonio
authors.initials: A
authors.lastname: Ordoñez
authors.forename: Encarnación
authors.initials: E
authors.lastname: Gutierrez
authors.forename: Manuel
authors.initials: M
authors.lastname: Leal
mesh_terms: D015703:Antigens, CD / Q000096:biosynthesis; D000943:Antigens, Differentiation / Q000235:genetics / Q000276:immunology*; D002454:Cell Differentiation; D049109:Cell Proliferation; D005260:Female; D005312:Fetal Blood / Q000166:cytology; D015321:Gene Rearrangement / Q000235:genetics / Q000276:immunology*; D006801:Humans; D016133:Polymerase Chain Reaction; D011948:Receptors, Antigen, T-Cell / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D015203:Reproducibility of Results; D013950:Thymus Gland / Q000166:cytology / Q000254:growth & development / Q000276:immunology / Q000378:metabolism*
chemical_list: D015703:Antigens, CD; D000943:Antigens, Differentiation; D011948:Receptors, Antigen, T-Cell