Ryuta Takizawa

Mast cell-IgE-and mast cell-structural cell interactions in allergic airway disease.

Allergic diseases like atopic rhinitis, bronchial asthma, and urticaria are prevalent and on the rise. Mast cells are known to play a central role in the immediate phase reaction of allergic diseases through the IgE-mediated release of a variety of chemical mediators like histamine, leukotrienes, and prostaglandins. On the other hand, T lymphocytes, basophils and eosinophils are thought to be responsible in inducing the late phase response. Yet, recent studies show that the mast cell cannot be simplistically assigned a role in the immediate phase allergic response, and that this cell plays a crucial role in ongoing allergic inflammation, including the development of hyper-responsiveness. In the present article, the author will try to discuss the integrated roles of mast cells in IgE-mediated allergic inflammation with specific emphasis on the roles of mast cell-IgE networking and mast cell-structural cell interactions in the late phase allergic response and chronic allergic inflammation.

Increased expression of HLA‐DR and CD86 in nasal epithelial cells in allergic rhinitics: antigen presentation to T cells and up‐regulation by diesel exhaust particles

Background A proportion of nasal epithelial cells (NEC) in patients with allergic rhinitis (AR) are known to express the major histocompatibility complex Class II molecule (HLA‐DR).

Novel Roles of Mast Cells in Modulating IgE-Mediated Allergic Inflammation

Mast cells play a central role in the immediate-phase allergic reaction through the IgE-mediated release of a variety of chemical mediators such as histamine, leukotrienes and prostaglandins. On the other hand, T lymphocytes, basophils and eosinophils are thought to be responsible for inducing the late-phase response. Yet, whether the mast cell can be simplistically assigned a role in the immediate-phase allergic reaction, and whether the cell is necessary for the ongoing allergic response, including the development of hyperresponsiveness, remain to be completely studied. Here, we will discuss the integrated roles of mast cells in IgE-mediated allergic inflammation.

Distribution of Mast Cells in Inverted Papilloma and Squamous Cell Carcinoma of the Nose

An increased number of mast cells is found in the epithelial layer of the nasal mucosa of allergic subjects. However, the mechanism of accumulation of the intraepithelial mast cells has not yet been clarified. We have previously shown that the increase of intraepithelial mast cells is related to the proliferation of nasal epithelial cells in vivo, and inverted papilloma and squamous cell carcinoma of the nose seem to be in vivo proliferative states of nasal epithelium. To clarify the mechanism of the accumulation of intraepithelial mast cells, we studied the relationship between nasal tumors of epithelial cell origin and the accumulation of mast cells. Accumulation of mast cells was observed in the nasal inverted papilloma, especially within 50μm from the basement membrane at the tumor site, which might be the site of maximum proliferation of tumor cells as well as secretion of cytokines. The majority of mast cells accumulated were formalin sensitive mast cells (mainly MMCs). On the other hand, in the squamous cell carcinoma of the maxillary sinus, fewer mast cells were found. Results of this study suggest that the accumulation of intraepithelial mast cells is associated with the proliferation of nasal epithelial cells.