Acquisition of New Migratory Properties by Highly Differentiated CD4+CD28null T Lymphocytes in Rheumatoid Arthritis Disease

IL-10 indirectly modulates functional activity of CD4+CD28null T-lymphocytes through LFA-3 and HLA class II inhibition

Expansion of CD4+CD28null T-lymphocytes is common in chronic heart failure (CHF) patients. Its ability to produce high levels of proinflammatory cytokines is probably the key role of these cells in CHF. IL-10 is a candidate for limiting CD4+CD28null T-lymphocyte responses, whereas tumour necrosis factor (TNF) is the cytokine most closely involved in the loss of CD28 expression. Serum levels of TNF and IL-10 were measured in 65 CHF patients (mean age, 65.2 ± 13.84 years). Patients with an IL-10/TNF ratio ≥1 had significantly lower levels of CD4+CD28null T-lymphocytes than those with a ratio <1. In vitro, IL-10 reduced the frequency of proliferative CD4+CD28null T-lymphocytes stimulated with anti-CD3. Pre-treatment with IL-10 before anti-CD3 stimulation was required for the cytokine to inhibit TNF production by CD4+CD28null T-lymphocytes. In addition to the previously described effect of IL-10 on HLA-DR and ICAM-1 expression, LFA-3 protein and mRNA levels were reduced in the presence of the cytokine in monocytes. IL-10 inhibition on CD4+CD28null T-lymphocytes may be mediated by a reduction in HLA class II and LFA-3 expression because blocking interactions with these costimulators has similar effects to those of IL-10 treatment. Moreover, costimulation through CD2/LFA-3 interaction is enough to induce proliferation and cytokine production in CD4+CD28null T-lymphocytes.

Activation of senescence in critically ill patients: mechanisms, consequences and therapeutic opportunities

Whereas aging is a whole-organism process, senescence is a cell mechanism that can be triggered by several stimuli. There is increasing evidence that critical conditions activate cell senescence programs irrespective of patient's age. In this review, we briefly describe the basic senescence pathways and the consequences of their activation in critically ill patients. The available evidence suggests a paradigm in which activation of senescence can be beneficial in the short term by rendering cells resistant to apoptosis, but also detrimental in a late phase by inducing a pro-inflammatory and pro-fibrotic state. Senescence can be a therapeutic target. The use of drugs that eliminate senescent cells (senolytics) or the senescence-associated phenotype (senomorphics) will require monitoring of these cell responses and identification of therapeutic windows to improve the outcome of critically ill patients.