title: Expression of the T-helper 2-specific chemokine receptor CCR4 on CCR10-positive lymphocytes in atopic dermatitis skin but not in psoriasis skin.
abstract: BACKGROUND
  Atopic dermatitis (AD) and psoriasis are inflammatory skin diseases. AD is generally perceived as a T-helper (Th) 2-dominated disease whereas psoriasis is a Th1-dominated disease. The chemokine cutaneous T-cell attracting chemokine (CTACK) and its receptor CCR10 attract skin-homing lymphocytes to inflamed skin, suggesting that CCR10+ cells in AD and psoriasis should be of Th2 and Th1 type, respectively. The chemokine receptor CCR4 is expressed selectively on Th2 lymphocytes and its ligand thymus and activation-regulated chemokine (TARC) is upregulated in AD lesions, suggesting that the CCR10+ cells in AD lesions should also express CCR4.
  
  
  OBJECTIVE
  To examine the coexpression of CCR10 and CCR4 on skin-invading lymphocytes in AD and psoriasis lesions as well as the Th1/Th2 cytokine expression of the CCR10+ lymphocytes.
  
  
  METHODS
  Skin biopsies from AD and psoriasis patients were double stained with antibodies against CCR10-CCR4, CCR10-CCR5, CCR10-interleukin (IL)-2 and CCR10-IL-4.
  
  
  RESULTS
  The CCR10+ cells in AD showed a mixed IL-2/IL-4 expression pattern, and a minor proportion expressed CCR4, whereas a large proportion of the CCR4+ cells did not express CCR10. In psoriasis the CCR10+ cells only expressed IL-2, and no CCR4 expression was detected.
  
  
  CONCLUSIONS
  The CCR10+ lymphocytes invading the skin in AD and psoriasis have different Th1/Th2 profiles, as measured by both their cytokine and chemokine receptor expression. This suggests that the CCR10+ subpopulation of lymphocytes is made up of different Th1/Th2 subsets. However, the Th1/Th2 lymphocytes of AD and psoriasis were either CCR10+ or CCR10-, suggesting that both the Th1 and Th2 subpopulation can be subdivided further. CCR4 was found only in AD skin and on both CCR10+ and CCR10- cells, supporting the hypothesis of TARC and CTACK as being independent lymphocyte-attracting chemokines in AD.
mesh_terms: D000328:Adult; D003876:Dermatitis, Atopic / Q000276:immunology*; D005260:Female; D006801:Humans; D007376:Interleukin-2 / Q000378:metabolism; D015847:Interleukin-4 / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D011565:Psoriasis / Q000276:immunology* / Q000378:metabolism; D054447:Receptors, CCR10; D054398:Receptors, CCR4; D019707:Receptors, Chemokine / Q000276:immunology* / Q000378:metabolism; D018418:Th2 Cells / Q000276:immunology*
chemical_list: C515706:CCR10 protein, human; C515354:CCR4 protein, human; D007376:Interleukin-2; D054447:Receptors, CCR10; D054398:Receptors, CCR4; D019707:Receptors, Chemokine; D015847:Interleukin-4