Immunology and aging.

Aging is accompanied by numerous functional and phenotypic changes in T cells, B cells and monocytes/macrophages; moreover, increases in autoimmunity, infections and occurrence of cancer have been reported in aged people. Healthy elderly persons, defined according to the criteria of the SENIEUR protocol, show various alterations in immunocompetent cells. Recent data have shown that the distribution of the subsets of peripheral blood, T-cell subtypes, is influenced by age.

Effects of heparin and aspirin on circulating P-selectin, E-selectin and von Willebrand Factor levels in healthy men.

As thrombin stimulates P-selectin expression on platelets and its release into plasma, we hypothesized that enhancing antithrombin activity by unfractionated heparin (UFH) could decrease plasma levels of circulating (c)P-selectin, (c)E-selectin, and von Willebrand Factor (vWF). Hence the effect of UFH and aspirin were examined on these activation markers in healthy volunteers. UFH decreased cP-selectin levels by -10% (CI: -16 - (-4%); P = 0.

Endotoxin down-modulates granulocyte colony-stimulating factor receptor (CD114) on human neutrophils.

During infection, the development of nonresponsiveness to granulocyte colony-stimulating factor (G-CSF) may be influenced by the down-modulation of G-CSF receptor (G-CSFR) by cytokines. This down-modulation was studied during experimental human endotoxemia. Healthy volunteers received either 2 ng/kg endotoxin (lipopolysaccharide [LPS], n=20) or placebo (n=10) in a randomized, controlled trial.

Effects of erythropoietin on platelet reactivity and thrombopoiesis in humans.

A recent study in dogs suggested that erythropoietin (EPO) not only promotes the synthesis of increased numbers of reticulated platelets but that these newly produced platelets are hyperreactive compared with controls. Because of the increasing use of EPO in the perioperative setting, we characterized the effects of EPO on platelet reactivity in healthy human volunteers. In a randomized, controlled trial, we studied the effects of EPO on platelet reactivity, thrombopoiesis, and endothelial activation in circumstances similar to those of autologous blood donation.

Monitoring of aspirin (ASA) pharmacodynamics with the platelet function analyzer PFA-100.

Background: Anti-platelet drug therapy is currently performed without monitoring, because the established method of platelet aggregometry is cumbersome. The recently developed platelet function analyzer PFA-100 measures shear stress dependent, collagen epinephrine (CEPI) and collagen adenosine diphosphate (CADP) induced platelet plug formation. As the PFA-100 provides a valuable tool to detect patients with platelet dysfunction more efficiently and cost-effectively than aggregometry, we investigated its potential to monitor the efficacy of aspirin treatment.