CD4+ CD8+ (thymocyte-like) T lymphocytes present in blood and skin from patients with atopic dermatitis suggest immune dysregulation.
BACKGROUND
Atopic dermatitis (AD) is a chronic inflammatory skin disease expressed early in life. Disease development is primarily determined by as yet unknown genetic factors, leading to the accumulation of activated T lymphocytes in the skin.


OBJECTIVE
To investigate the nature of these T cells.


METHODS
T-cell lines could be established from AD skin biopsies, but not from normal skin or AD peripheral blood, when placed in RPMI 1640 medium with 10% human AB serum, antibiotics, and the T-lymphocyte growth factors interleukins 2 and 4. The cell lines were subjected to phenotypic analysis using a fluorescence-activated cell sorter and compared with lymphocytes from AD and normal control peripheral blood.


RESULTS
T-cell lines from 22 of 24 consecutive skin biopsies taken from 24 adult patients with AD were established. All cells were T lymphocytes expressing several activation markers. A significant proportion of the lymphocytes had stable expression of a CD4+ CD8+ phenotype (26% +/- 6%; mean +/- SEM). Such double-positive T lymphocytes are normally only seen in the thymus and not in the peripheral immune system. CD4+ CD8+ cells in peripheral blood of the patients (12.5% +/- 3.3%) were also detected.


CONCLUSIONS
We suggest that a basic pathophysiological change in AD may be a faulty maturation of the T-lymphocyte system, leading to skin inflammation with CD4+ CD8+ T lymphocytes resembling immature T cells. This is likely to lead to skewing of many immune reactions in the patients.
Bang
K
K
Department of Dermatology, Marselisborg Hospital, DK-8000 Aarhus C., Denmark. karen.bang@dadlnet.dk
Lund
M
M
Wu
K
K
Mogensen
S C
SC
Thestrup-Pedersen
K
K
D000293:Adolescent; D000328:Adult; D000911:Antibodies, Monoclonal / Q000276:immunology; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology* / Q000473:pathology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology* / Q000473:pathology; D002455:Cell Division / Q000276:immunology; D002460:Cell Line; D048429:Cell Size; D003876:Dermatitis, Atopic / Q000201:enzymology / Q000276:immunology*; D005260:Female; D006801:Humans; D007111:Immunity, Cellular; D016130:Immunophenotyping; D008213:Lymphocyte Activation / Q000276:immunology; D008297:Male; D008875:Middle Aged; D012867:Skin / Q000201:enzymology / Q000276:immunology*; D019098:Telomerase / Q000378:metabolism; D016615:Telomere / Q000648:ultrastructure
D000911:Antibodies, Monoclonal; D019098:Telomerase