Progenitor cells undergo T cell receptor (TCR) gene rearrangements during their intrathymic differentiation to become T cells. Rearrangements of the variable (V), diversity (D), and joining (J) segments of the TCR genes result in deletion of the intervening chromosomal DNA and the formation of circular episomes as a byproduct. Detection of these extrachromosomal excision circles in T cells loca...

INTRODUCTION Juvenile idiopathic arthritis is a heterogeneous T cell-mediated autoimmune disease with symptoms of premature aging of the immune system (immunosenescence). The present work is an investigation of immunosenescence parameters, such as quantity of naive and CD28- T cells, T cell receptor excision circles, relative telomere length and alterations of peripheral T cell replication, and...

PURPOSE The T cell repertoire in patients with advanced cutaneous T cell lymphoma (CTCL) is significantly contracted despite the presence of relatively normal absolute numbers of T cells. We propose that many normal T cells were being lost in patients with CTCL, with the remaining normal T cells expanding clonally to fill the T cell compartment. T-cell receptor excision circles (TREC) form as a...

Levels of Kappa-deleting recombination excision circles (KRECs), T-cell receptor excision circles (TRECs), and T-cell repertoire diversity were evaluated in 1038 samples of 124 children with primary immunodeficiency, of whom 102 (54 with severe combined immunodeficiency and 48 with other types of immunodeficiency) underwent hematopoietic stem cell transplantation. Twenty-two not transplanted pa...

T-cell receptor excision circles (TREC) in peripheral blood mononuclear cells (PBMC) were evaluated in the Genetic Resistance to Human Immunodeficiency Virus cohort of HIV-1-seropositive non-progressors (NP). After a short follow-up, NP were sub-grouped as stable (NP-S), or with signs of disease progression (NP-P). Initial TREC were higher in NP-S compared to NP-P ( P = 0.002), even after adjus...

The immune reconstitution after allogeneic hematopoietic stem cell transplantation comprises thymus-dependent and thymus-independent pathways. We wanted to improve the understanding of this complex process using two different measurements at definite checkpoints of T-cell neogenesis. We therefore assessed the thymus-dependent pathway by combining measurements of single joint T-cell receptor exc...