T cells of atopic asthmatics preferentially infiltrate into human bronchial xenografts in SCID mice

Human Nasal Polyp Microenvironment Maintained in Viable and Functional States as Xenografts in SCID Mice

Objectives:

We undertook to maintain human nasal polyp tissue in a viable and functional state in SCID (severe combined immunodeficiency) mice.

Methods:

Small, nondisrupted pieces of human nasal polyp tissues were subcutaneously implanted into SCID mice depleted of natural killer cells. The resulting xenografts were examined histologically, and the sera were evaluated for the presence of human protein.

Results:

The original histologic architecture of the polyp was maintained in the xenografts. The tissues, including pseudostratified columnar epithelial–lined polyps and subepithelial stroma, remained viable, and goblet cells continued to produce mucin for up to 26 weeks after engraftment. Human inflammatory leukocytes, including CD3+ T cells, CD20+ B cells, CD138+ plasma cells, and CD68+ monocytes and/or macrophages, were present. Identification of human immunoglobulin and human interferon-γ in the sera of xenograft-bearing mice indicated that the B cells or plasma cells and T cells within the xenografts remained functional for 2 weeks after engraftment.

Conclusions:

The ability to engraft and maintain nasal polyps provides an in vivo human/mouse chimeric model with which to investigate the role of inflammatory leukocytes and stromal cells in the maintenance and progression of polyposis and to determine how exogenous cytokines may alter the interaction of inflammatory cells, stromal cells, and epithelial cells in the polyp.

Dangerous exercise: lessons learned from dysregulated inflammatory responses to physical activity

Exercise elicits an immunological “danger” type of stress and inflammatory response that, on occasion, becomes dysregulated and detrimental to health. Examples include anaphylaxis, exercise-induced asthma, overuse syndromes, and exacerbation of intercurrent illnesses. In dangerous exercise, the normal balance between pro- and anti-inflammatory responses is upset. A possible pathophysiological mechanism is characterized by the concept of exercise modulation of previously activated leukocytes. In this model, circulating leukocytes are rendered more responsive than normal to the immune stimulus of exercise. For example, in the case of exercise anaphylaxis, food-sensitized immune cells may be relatively innocuous until they are redistributed during exercise from gut-associated circulatory depots, like the spleen, into the central circulation. In the case of asthma, the prior activation of leukocytes may be the result of genetic or environmental factors. In the case of overuse syndromes, the normally short-lived neutrophil may, because of acidosis and hypoxia, inhibit apoptosis and play a role in prolongation of inflammation rather than healing. Dangerous exercise demonstrates that the stress/inflammatory response caused by physical activity is robust and sufficiently powerful, perhaps, to alter subsequent responses. These longer term effects may occur through as yet unexplored mechanisms of immune “tolerance” and/or by a training-associated reduction in the innate immune response to brief exercise. A better understanding of sometimes failed homeostatic physiological systems can lead to new insights with significant implication for clinical translation.

Cytokine production, activation marker, and skin homing receptor in children with atopic dermatitis and bronchial asthma

T cells are known to develop a critical role in the pathogenesis of atopic dermatitis (AD) and bronchial asthma. T cells involved in AD express the skin homing receptor CLA, but no lung homing receptor has been identified in bronchial asthma. We compared different cell markers and the cytokine production in T cells from children with AD or bronchial asthma. We studied the involvement of CLA+ and CLA- T-cell subpopulations in these diseases. We studied 20 children with acute AD lesions, 15 with mild persistent asthma, and 15 non-atopic controls. All patients were sensitized to house dust mite (DP) and evaluated during the acute phase. Total and specific IgE were measured by immunoassay and the expression of different cell markers and the cytokine production was analyzed by flow cytometry in peripheral blood mononuclear cells. Total IgE was significantly higher in AD children and IgE to DP in the asthmatic children. There was a significant increase in CD25+ CD4+ cells in asthmatic children and in HLA-DR+ CD4+ and HLA-DR+ CD8+ cells in AD. In the CD4+ subsets, there was an increase in IL-13, IL-5 and TNF-alpha in AD compared to controls, a decrease in IFN-gamma in asthmatic children compared to controls, and an increase in IL-13, IL5, IL2, TNF-alpha, and IFN-gamma in the AD compared to asthmatic children. Changes in cytokine production were mainly detected in CLA+ cells in AD and in CLA- cells in asthma. Differences exist in total and specific IgE, activation markers, and cytokine patterns between AD children and children with asthma, with the former expressing a Th2 pattern whereas in asthmatic children we only detected a decrease in IFN-gamma. Moreover, the subpopulations (CLA+ vs. CLA-) expressing these changes were different, indicating that the underlying mechanisms in the two diseases are not exactly the same.