Immunobiology
-
We recently identified autocrine interferon (IFN)beta as a novel mechanism mediating tumor necrosis factor (TNF)alpha-induced expression of inflammatory genes in airway smooth muscle (ASM) cells, including CD38, known to regulate calcium signaling. Here, we investigated the putative involvement of IFNbeta in regulating TNFalpha-induced airway hyper-responsiveness (AHR), a defining feature of asthma. Using our pharmacodynamic model to assess ex vivo AHR isolated murine tracheal rings, we found that TNFalpha-induced enhanced contractile responses to carbachol and bradykinin was abrogated by neutralizing anti-IFNbeta antibody or in tracheal rings deficient in CD38. ⋯ In a well-characterized model of allergic asthma (mice sensitized and challenged with Aspergillus fumigatus (Af)), we found heightened expression of both IFNbeta and CD38 in the airways. Furthermore, allergen-associated AHR to methacholine, assessed by lung resistance and dynamic compliance, was completely suppressed in CD38-deficient mice, despite the preservation of airway inflammation. These data provide the first evidence that ASM-derived IFNbeta and CD38 may play a significant role in the development of TNFalpha-associated AHR.
-
It has become increasingly evident that pulmonary surfactant proteins, SP-A and SP-D, present in the alveolar and bronchial epithelial fluid linings, not only play significant functions in the innate defense mechanism against pathogens, but also are involved in immunomodulatory roles, which result in the protection against, and resolution of, allergen-induced airway inflammation. Studies on allergen-sensitized murine models, and asthmatic patients, show that SP-A and SP-D can: specifically bind to aero-allergens; inhibit mast cell degranulation and histamine release; and modulate the activation of alveolar macrophages and dendritic cells during the acute hypersensitive phase of allergic response. ⋯ Intranasal administration of SP-D significantly attenuated the asthmatic-like symptoms seen in allergen-sensitized wild-type, and SP-D-deficient, mice. These important findings provide a new insight of the role that surfactant proteins play in handling environmental stimuli and in their immunoregulation of airway inflammatory disease.
-
A review of 250 patients with the catastrophic antiphospholipid (Asherson's) syndrome (CAPS) taken from the web site organized by the Europhospholipid Group (http://www.med.ub.es/MIMMUN/FORUM/CAPS. HTM) is presented in this paper. A short historical overview of the antiphospholipid syndrome (APS) is followed by a description of the "triggering" factors, associated autoimmune diseases, clinical presentation, presumed pathogenesis, prognosis, mode of death and suggested therapies. ⋯ Treatment may have to be continued for several weeks. Parenteral antibiotics may be indicated where an underlying infection is suspected. Antifungal therapy may also be indicated with prolonged treatment and the use of the monoclonal anti-CD20 molecule, Rituximab, has proven useful in those patients where thrombocytopenia poses a major risk of hemorrhage.
-
Myocardial injury from ischemia can be aggravated by reperfusion of the jeopardized area. The precise underlying mechanisms have not been clearly defined, but proinflammatory events including complement activation play important roles. ⋯ Inhibition of local complement activation was accompanied by improvement of myocardial function and perfusion of the previously ischemic myocardium. Leukocyte endothelial cell-cell interaction was strikingly reduced in the reperfused tissues as afflection of anti-inflammatory effect.
-
IL-4 is a pleiotropic cytokine which plays a pivotal role in shaping immune responses. The effects of IL-4 are mediated after binding to high affinity receptor complexes present on hematopoietic as well as non-hematopoietic cells. ⋯ IL-4 effects are modulated by soluble forms of the respective receptor molecules which are produced by several immune cells in a regulated manner. The biological impact of recently described IL-4R allotypes of mice and humans as well as the results of studies with IL-4R knockout mice will be particularly emphasized.