Premium
Proposal of inducible skin‐associated lymphoid tissue ( iSALT )
Author(s) -
Ono Sachiko,
Kabashima Kenji
Publication year - 2015
Publication title -
experimental dermatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.108
H-Index - 96
eISSN - 1600-0625
pISSN - 0906-6705
DOI - 10.1111/exd.12716
Subject(s) - lymph , lymphatic system , immunology , microbiology and biotechnology , contact dermatitis , dendritic cell , epidermis (zoology) , biology , chemistry , medicine , pathology , immune system , allergy , anatomy
In the 1980s, Streilein et al. introduced the term ‘skinassociated lymphoid tissue ( SALT )’ based on observations that revealed the existence of T cells and dendritic cells ( DC s) in the skin and that T cells are activated in the skin draining lymph nodes. However, in the perspective of SALT , it remains still unclear whether and how cellular components in the skin interact with each other. In addition, whether the T‐cell activation occurs in the skin in situ has also been unrevealed. With the close observation of a skin specimen obtained from a patient with contact dermatitis, we discovered that dermal DC s ( dDC s) clustered and closely attached to T cells. Thus, we hypothesized that this clustering might be essential for the establishment of the dermatitis and the T‐cell activation in situ. Through the detailed examination of the elicitation phase of contact hypersensitivity as a murine model of contact dermatitis, we demonstrated the formation of sequential leukocyte clusters at the postcapillary venules. The clusters include perivascular macrophages that are activated by IL ‐1a produced by keratinocytes and dDC s that are attracted by these macrophages through CXCL 2 signalling, both of which are essential for the efficient activation of memory T cells in situ. The structure does not exist in the steady state, but is ‘induced’ in response to local inflammatory conditions. Herein, we propose that this structure to be termed as ‘inducible SALT ( iSALT )’.