Evaluation of thymic function, regulatory T cells and activation, proliferation and death of T lymphocytes in patients with systemic lupus erithematosus

Abstract

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease whose pathogenesis remains undefined. Immunological changes characterized by loss of self-tolerance mechanisms are central changes in this disease. In this context, a number of changes are described in the population of T cells. Thymus is the organ responsible for T lymphocytes maturation and is important in maintaining self-tolerance and homeostasis of the immune system. Recently a new methodology was described for the analysis of thymic function in peripheral blood. It is the quantification of "circles excised by rearrangement of the TCR (TREC), a marker of recent thymic emigrants generated during TCR gene rearrangement in the thymus. However, the levels of TREC in peripheral blood may be affected by other factors such as activation, proliferation of peripheral T lymphocytes and cell death. Moreover, naturally regulatory T-cells (CD4+ CD25+ FOXP3+) derived from functionally mature populations in the thymus, plays an important role in controlling immune responses. The present study aims to evaluate the levels of TREC and TREG in peripheral lymphocytes in patients with active and inactive SLE and the rate of proliferation, apoptosis and activation of T lymphocytes. The results will be compared with healthy subjects matched for sex and age. The results of this study may contribute to a better understanding of the interference of proliferation, apoptosis and activation of T lymphocytes in the levels of TREC in peripheral blood as well as to evaluate a possible correlation between TREC and TREG, opening perspectives for a better therapeutic approach for these patients. (AU)