No abstract

Autophagy, the cytoprotection mechanism that takes place under metabolic impairment, has been implicated in the pathogenesis of autoimmunity. Here, we investigated the spontaneous and induced autophagic behavior of T lymphocytes from patients with systemic lupus erythematosus (SLE) compared with that of T lymphocytes from healthy donors by measuring the autophagy marker microtubule-associated protein 1 light chain 3 (LC3)-II. No significant differences in spontaneous autophagy were found between T lymphocytes from patients with SLE and from healthy donors, apart from CD4(+) naive T cells from patients with SLE in which constitutively higher levels of autophagy (P<0.001) were detected. At variance, whereas treatment of T lymphocytes from healthy donors with serum IgG from patients with SLE resulted in a 2-fold increase in LC3-II levels (P<0.001), T lymphocytes from SLE patients were resistant to autophagic induction and also displayed an up-regulation of genes negatively regulating autophagy, e.g., α-synuclein. These findings could open new perspectives in the search for pathogenetic determinants of SLE progression and in the development of therapeutic strategies aimed to recover T-cell compartment homeostasis by restoring autophagic susceptibility.

Autophagy is a lysosome-mediated catabolic process that allows cells to degrade unwanted cytoplasmic constituents and to recycle nutrients. Autophagy is also involved in innate and adaptive immune responses, playing a key role in interactions against microbes, in antigen processing for major histocompatibility complex (MHC) presentation, and in lymphocyte development, survival, and proliferation. Over recent years, perturbations in autophagy have been implicated in a number of diseases, including autoimmunity. Systemic lupus erythematosus (SLE) is a multifactorial disease characterized by autoimmune responses against self-antigens generated by dying cells. Genome-wide association studies have linked several single-nucleotide polymorphisms (SNPs) in the autophagy-related gene Atg5 to SLE susceptibility. Loss of Atg5-dependent effects, including clearance of dying cells and cell antigen presentation, might contribute to the autoimmunity and inflammation associated with SLE. Moreover, activation of the mammalian target of rapamycin (mTOR), a key player in the autophagy regulation, has recently been demonstrated in SLE, confirming an altered autophagy pathway in this disease. In the present review, we summarize the autophagy mechanisms, their molecular regulation, and their relevance in immunity and autoimmunity. The potential of targeting autophagy pathway in SLE, by developing innovative therapeutic approaches, has finally been discussed.

Objective. Estrogens influence many physiologic processes and are also implicated in the development or progression of numerous diseases, including autoimmune disorders. Aberrations of lymphocyte homeostasis that lead to the production of multiple pathogenic autoantibodies, including autoantibodies specific to estrogen receptor (ER), have been detected in the peripheral blood of patients with systemic lupus erythematosus (SLE). This study was undertaken to assess the presence of both anti-ER␣ and anti-ER␤ antibodies in sera from patients with SLE, to analyze the effect of these antibodies on peripheral blood T lymphocyte homeostasis, and to evaluate their role as determinants of disease pathogenesis and progression.Methods. Anti-ER antibody serum immunoreactivity was analyzed by enzyme-linked immunosorbent assay in samples from 86 patients with SLE and 95 healthy donors. Phenotypic and functional analyses were performed by flow cytometry and Western blotting.Results. Anti-ER␣ antibodies were present in 45% of the patients with SLE, whereas anti-ER␤ antibodies were undetectable. In healthy donors, anti-ER␣ antibodies induced cell activation and consequent apoptotic cell death in resting lymphocytes as well as proliferation of anti-CD3-stimulated T lymphocytes. A significant association between anti-ER␣ antibody values and clinical parameters, i.e., the SLE Disease Activity Index and arthritis, was found.Conclusion. Our data suggest that anti-ER␣ autoantibodies interfere with T lymphocyte homeostasis and are significantly associated with lupus disease activity.The involvement of estrogens, which influence many physiologic processes, has been shown in the development or progression of several autoimmune disorders (1-4). There is evidence that 17␤-estradiol directly modulates the development and function of immune cells, although the mechanism by which this might occur is not well understood (5,6). The primary mechanism of 17␤-estradiol activity is mediated by transcription activity of the intracellular estrogen receptors (ERs), ER␣ and ER␤, to produce genomic effects (7). A variety of cellular responses to physiologic concentrations of 17␤-estradiol occur rapidly, within seconds to a few minutes. These rapid estrogen-mediated effects (referred to as nongenomic) are triggered through the activation of membrane-associated ER and are independent of transcription pathways and protein synthesis.

Our study demonstrates that EBUS-TBNA can be effectively used not just for diagnosis but also for complete mutational testing.