Decreased numbers of signal-joint T cell receptor excision circle-containing CD4+ and CD8+ cells in systemic lupus erythematosus patients

Exploiting Signal Joint T Cell Receptor Excision Circle to Investigate the Impact of COVID-19 and Autoimmune Diseases on Age Prediction and Immunosenescence

Signal joint T cell receptor excision circles (sjTRECs) are a promising marker for age estimation and immunosenescence in different ethnic groups. Several limitations are expected to overshadow their use as accurate markers for age prediction. The current study was conducted to determine the influence of immunologic disorders, such as autoimmune diseases and COVID-19, on the accuracy of sjTRECs as molecular markers for age estimation and immunosenescence among living Egyptians. Peripheral blood sjTRECs level was measured by qPCR in 90 autoimmune patients, 58 COVID-19 patients, and 85 healthy controls. The mean dCt values were significantly (p = 0.0002) different between the three groups, with the highest values in healthy subjects, followed by autoimmune and COVID-19 patients. A significant negative correlation was identified between the sjTRECs levels and ages in all studied cases. There were significant positive correlations between chronological age and predicted age for healthy individuals, autoimmune, and COVID-19 patients with mean absolute deviations (MAD) of 9.40, 11.04, and 9.71, respectively. The two patients' groups exhibited early immunosenescence, which was more noticeable among the young adults with COVID-19 and autoimmune patients of age range (18-49 years). Autoimmunity may represent a critical factor impacting the accuracy of sjTRECs quantitation for age prediction.

Molecular Mechanisms of Immunosenescene and Inflammaging: Relevance to the Immunopathogenesis and Treatment of Multiple Sclerosis

Aging is characterized, amongst other features, by a complex process of cellular senescence involving both innate and adaptive immunity, called immunosenescence and associated to inflammaging, a low-grade chronic inflammation. Both processes fuel each other and partially explain increasing incidence of cancers, infections, age-related autoimmunity, and vascular disease as well as a reduced response to vaccination. Multiple sclerosis (MS) is a lifelong disease, for which considerable progress in disease-modifying therapies (DMTs) and management has improved long-term survival. However, disability progression, increasing with age and disease duration, remains. Neurologists are now involved in caring for elderly MS patients, with increasing comorbidities. Aging of the immune system therefore has relevant implications for MS pathogenesis, response to DMTs and the risks mediated by these treatments. We propose to review current evidence regarding markers and molecular mechanisms of immunosenescence and their relevance to understanding MS pathogenesis. We will focus on age-related changes in the innate and adaptive immune system in MS and other auto-immune diseases, such as systemic lupus erythematosus and rheumatoid arthritis. The consequences of these immune changes on MS pathology, in interaction with the intrinsic aging process of central nervous system resident cells will be discussed. Finally, the impact of immunosenescence on disease evolution and on the safety and efficacy of current DMTs will be presented.

Reduced T-Cell Thymic Export Reflected by sj-TREC in Patients with Coronary Artery Disease

AIM

Immunologic dysfunction was recently found to be one of the most important mechanisms underlying the initiation and development of atherosclerosis. Thymus involution can contribute to immune disturbance and disequilibrium of T-cell subsets. This study aimed to explore whether recent thymic emigration (RTE) is impaired in patients with coronary artery disease (CAD).

METHODS

Content of signal-joint T cell receptor excision circles (sj-TREC) in T lymphocytes, a molecular marker of RTE, was assessed among CAD patients and age-matched controls. Monochrome multiplex quantitative PCR method was used to assess the samples' telomere length in order to exclude the potential influence of T cell proliferation on the dilution of sj-TREC. Patients were grouped according to Gensini score (GS) (low, GS ＜18; intermediate, GS 18-41; high, GS ＞41). Ordinary logistic regression models were used to determine potential risk factors for CAD and GS tertiles.

RESULTS

Average copy numbers of sj-TREC per 10(6) T lymphocytes among patients with unstable angina, stable angina, and controls were 726±429, 1213±465, and 1795±838, respectively (P＜0.001). However, there was no significant difference in telomere length among groups. Moreover, the content of sj-TREC in the high GS group was most significantly reduced than the low GS group (P＜0.001). Multivariate logistic regression analysis revealed that lower sj-TREC was independently associated with the progression of CAD (OR=0.44, P＜0.001) and higher GS (OR=0.4, P＜0.001).

CONCLUSION

Impaired RTE could be partly responsible for CAD development. Mechanisms may be involved in the disturbance of T lymphocyte compartment and interruption of maintained immune tolerance resulting from thymus involution.

Increased concentration of T-cell receptor rearrangement excision circles (TREC) in peripheral blood in Graves' disease

BACKGROUND

T-cell receptor rearrangement excision circles (TREC) are circular DNA molecules generated during T-cell maturation in the thymus. Recent studies suggested that a decreased TREC concentration in peripheral blood may be a general feature of autoimmunity. Our purpose was to assess the TREC concentration in Graves' disease (GD).

METHODS

TREC concentration was assessed by real time PCR in DNA samples isolated from peripheral blood leucocytes among younger (n = 94, age range 6-29 years) and older patients with GD (n = 93, age range 57-80 years) and age-matched controls (n = 206).

RESULTS

TREC concentration decreased with age in all subjects, but it was significantly higher in GD compared with controls (P = 9·4 × 10(-10) ). TREC concentration was higher (P = 0·0038) in hyperthyroid (n = 78) than euthyroid (n = 82) patients with GD, but in both groups, it remained increased relative to controls (P = 2·2 × 10(-11) and P = 4·4 ×10(-7) , respectively).

CONCLUSIONS

Patients with GD, particularly those with hyperthyroidism, have increased concentration of TREC which may suggest increased rather than decreased thymic activity. Thus, GD does not follow the paradigm suggested for other autoimmune disorders which links autoimmunity with thymic senescence.