Effects of caffeine and phosphodiesterase inhibitors on activation of neonatal T lymphocytes.

Caffeine and selective PDE inhibitors are widely used in clinical management of preterm and term neonates. However, little is known about how these compounds interact with the neonatal adaptive immune system. We aimed to describe the effects of caffeine, milrinone and sildenafil on the activation and cytokine production of T cells from umbilical cord blood (UCB) compared to adult peripheral blood (APB). We isolated mononuclear cells from 10 APB and 6 UCB samples. We assessed intracellular cytokine production (IFN-γ, IL-2, IL-4, IL-6, IL-17) of stimulated CD4 cells and parameters of calcium influx and ROS production following treatment with caffeine, milrinone, sildenafil, dbcAMP or a specific A2A receptor antagonist, ZM241385 using flow cytometry. In ABP, only ZM241385 caused a 1.14-fold increase in calcium influx, while all compounds increased calcium influx in UCB. This effect was more pronounced in case of caffeine (1.41-fold) and dbcAMP (1.3-fold) compared to milrinone (1.22-fold), sildenafil (1.23-fold) or ZM241385 (1.23-fold). Intracellular levels of the studied cytokines were unaffected by the applied compounds in both APB and UCB samples. Caffeine increases calcium influx upon activation in neonatal T lymphocytes to a larger extent than milrinone or sildenafil. This effect appears to be mediated primarily via increased cAMP levels rather than A2A receptor inhibition. Overall, the application of caffeine, sildenafil or milrinone does not appear to have immunosuppressive effects on neonatal T cells.

The Impact of Anti-TNF Therapy on CD4+ and CD8+ Cell Subsets in Ankylosing Spondylitis.

OBJECTIVES: Ankylosing spondylitis (AS) is a chronic, progressive immune-mediated inflammatory disease, driven primarily by Th1 and Th17 cells. Anti-TNF therapies are successfully used in AS to achieve and maintain remission. However, their influence on the composition of T-cell subsets is not clear. We aimed to characterize the changes in the T-cell repertoire after a long-term anti-TNF treatment in AS patients. METHODS: Twenty-two AS patients under long-term anti-TNF therapy were evaluated (15 anti-TNF responders and 7 nonresponders). A wide range of cell subtypes was analyzed with flow cytometry and compared with therapy-naïve and short-term data too. RESULTS: Key findings include decreased proportions of naïve CD4 and CD8 cells, increased frequencies of Th1 and Th17 cells and higher Th1/Th2 ratios in the long-term anti-TNF-treated patients (responders, nonresponders and total), which was found to be significant not only when compared with healthy controls, but also with therapy-naïve and short-term anti-TNF-treated AS patients. We noted several alterations within the various activated T-cell subsets - increase in CD4HLADR cells in responders, in CD8HLADR cells in the whole AS group and in responders, and in CD4CD25 cells in responders, and decrease in CD4CD69 cell percentages in long-term treated patients - becoming evident only after long-term anti-TNF therapy. CONCLUSIONS: This study provides a comprehensive assessment of the impact of anti-TNF therapy on the T-cell repertoire in AS. Changes in T-cell phenotype seem to develop progressively during therapy, even in inactive disease, and reflect an ongoing effector T-cell differentiation and activation, along with the parallel compensatory increase in regulatory T cells.

T-Cell Subsets in Rheumatoid Arthritis Patients on Long-Term Anti-TNF or IL-6 Receptor Blocker Therapy.

Data on the impact of biological therapies on the T-cell phenotype in rheumatoid arthritis are limited. Here, we prospectively measured the percentages of 15 circulating T-cell subtypes using flow cytometry. We obtained transversal and longitudinal data in 30 anti-TNF responders, 19 secondary anti-TNF nonresponders, and 43 IL-6R antagonist responders, before, 8 weeks and at least 6 months after biological therapy. Untreated RA patients and healthy controls were also included. The important findings are the following: (1) the proportion of regulatory T-cells (Tregs) which are decreased in untreated RA patients becomes normal in all long-term-treated groups; (2) in anti-TNF responders as well as in nonresponders, the frequencies of naïve CD4+ and CD8+ cells are lower, whereas those of proinflammatory Th1, Th2, and Th17 cells and HLA-DR+-activated cells are higher than those in untreated RA or healthy controls; (3) in IL-6R responders, Th1 proportion is decreased, while that of Th2 and Th17 is increased as compared to that in anti-TNF-treated patients and controls; (4) pending confirmation, a CD4CD69 ratio < 2.43 at baseline, could be useful to predict a good therapeutic response to anti-TNF therapy. This study provides comprehensive information regarding the long-term impacts of those biological therapies on the ecotaxis of T-cells in RA. The ClinicalTrials.gov registration number of our study is NCT03266822.

Impact of aging on calcium influx and potassium channel characteristics of T lymphocytes.

Adaptive immunity and T cell function are affected by aging. Calcium influx patterns, regulated by Kv1.3 and IKCa1 potassium channels, influence T cell activation. We aimed to compare calcium influx kinetics in CD8, Th1 and Th2 cells in human peripheral blood samples obtained from five different age groups (cord blood, 10-15 ys, 25-40 ys, 45-55 ys, 60-75 ys).We measured calcium influx using flow cytometry in samples treated with or without specific inhibitors of Kv1.3 and IKCa1 channels (MGTX and TRAM, respectively).Calcium influx was higher in Th1 cells of adults, however, its extent decreased again with aging. Importantly, these changes were not detected in Th2 cells, where the pattern of calcium influx kinetics is similar throughout all investigated age groups. MGTX had a more pronounced inhibitory effect on calcium influx in Th2 cells, while in Th1 cells the same was true for TRAM in the 25-40 ys and 45-55 ys groups. Calcium influx of CD8 cells were inhibited to a similar extent by both applied inhibitors in these groups, and had no effect in the elderly.Altered lymphocyte potassium channel inhibitory patterns, regulators of calcium influx kinetics, might contribute to the development of age-related changes of T cell function.

Prevalence of Regulatory T-Cell Subtypes in Preeclampsia.

PROBLEM: The prevalence of regulatory T cells (Tregs) is lower in preeclampsia (PE) compared with healthy pregnancy (HP). However, the proportion of recently described Treg subtypes has not been investigated. METHOD: Peripheral blood samples of 19 PE and 21 HP women in the third trimester were evaluated using flow cytometry for the prevalence of activated T cells and naive, effector, thymic, extrathymic, and exhausted Tregs. RESULTS: The prevalence of activated T cells and exhausted Tregs was higher in PE than in HP. The prevalence of the functionally most active effector Tregs is decreased, while naive Tregs appear to be unaffected in PE compared with HP. No difference was detected between Tregs according to their origin (thymic or extrathymic). CONCLUSION: The combination of lower effector Treg and higher exhausted Treg prevalence may account for the decrease in the functionality of Tregs in PE.