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Histological increase in inflammatory infiltrate in sun‐exposed skin of female subjects: the possible involvement of matrix metalloproteinase‐1 produced by inflammatory infiltrate on collagen degradation
Author(s) -
Hase T.,
Shinta K.,
Murase T.,
Tokimitsu I.,
Hattori M.,
Takimoto R.,
Tsuboi R.,
Ogawa H.
Publication year - 2000
Publication title -
british journal of dermatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.304
H-Index - 179
eISSN - 1365-2133
pISSN - 0007-0963
DOI - 10.1046/j.1365-2133.2000.03296.x
Subject(s) - pathology , haematoxylin , infiltration (hvac) , dermis , histiocyte , lymphatic system , staining , cd3 , medicine , cd68 , chemistry , immunohistochemistry , immunology , cd8 , immune system , physics , thermodynamics
To investigate morphological changes occurring during cutaneous photoageing, a correlation between the number of infiltrating cells in the dermis and the degree of collagen damage was examined using sections from clinically normal chronically sun‐exposed and sun‐protected skin of Japanese female subjects. Haematoxylin and eosin‐stained sections from 134 sun‐exposed (subjects aged 3–82 years) and 73 sun‐protected (subjects aged 1–86 years) areas demonstrated a predominant lymphoid cell and to a lesser extent histiocyte infiltration. The mean ± SD number of lymphoid cells and histiocytes in the sun‐exposed skin sections (427·0 ± 192·2 and 147·8 ± 83·3 cells/mm 2 , respectively) was significantly higher than in the sun‐protected skin sections (292·6 ± 98·3 and 125·9 ± 59·0 cells/mm 2 , respectively) ( P < 0·001 and P < 0·05, respectively), and the number of lymphoid cells in the sun‐exposed skin sections increased significantly with age up to 50 years ( r = 0·400, P < 0·001). Sun‐exposed skin sections with severe collagen degeneration had a significantly higher number of lymphoid cells than those with slightly degenerated collagen (mean 626·3 vs. 482·4 cells/mm 2 , P < 0·01). The mean count of mast cells in sun‐exposed skin was 202·0 cells/mm 2 ; this did not vary with the age of the subjects or the level of collagen damage. Immunohistochemical studies using 24 frozen sections identified most of the lymphoid cells infiltrating sun‐exposed skin as memory T lymphocytes (CD3+, CD4+ and CD45RO+). The number of cells which displayed immunoreactivity to matrix metalloproteinase (MMP)‐1 in the sun‐exposed skin sections was significantly higher than in the sun‐protected skin sections (mean 170·2 vs. 113·6 cells/mm 2 , P < 0·05). Among these cells were observed CD3 and MMP‐1 double‐stained T lymphocytes, and T lymphocytes contacting MMP‐1‐positive cells. These morphological observations suggest that T lymphocytes infiltrating photodamaged skin may play a part in the degeneration and reduction of collagen through MMP‐1 activity.