Psoriatic epidermal cells demonstrate increased numbers and function of non-Langerhans antigen-presenting cells.
The recent findings that the immunosuppressant cyclosporine A (CsA) improves psoriasis raises the possibility that cellular immune processes play a major role in the pathogenesis of psoriasis. We therefore investigated the phenotype and function of cells within psoriatic epidermis that can play a role in cellular immunologic reactivity. Double fluorescence microscopic studies with monoclonal antibodies of epidermal cells in suspension (EC) and of histologic sections demonstrated that involved psoriatic skin contained a significantly increased number of non-Langerhans cell T6-DR+ EC (4.9 + 2.1%) relative to uninvolved (0.3 +/- 0.1%), p less than 0.01. This non-Langerhans cell population was comprised of DR+ monocytes, DR+ activated T lymphocytes, a few DR+RFD1+ antigen-presenting cells (APC), and DR+ keratinocytes. Langerhans cell (LC) levels in EC suspension were not different between involved and uninvolved psoriatic epidermis. Functional studies demonstrated that involved psoriatic epidermal cells had an increased capacity to induce T-cell activation and proliferation relative to uninvolved EC (p less than 0.04). This increased APC activity was due to the non-LC T6-DR+HLe1+ APC population and not to DR+ keratinocytes. These results demonstrate that involved psoriatic epidermal cells contain both an increased number and function of antigen-presenting cells. The pathogenetic mechanisms in psoriasis may be related to ongoing cellular immune responses in the skin, and the effect of CsA may be mediated through a suppressive effect on the enhanced antigen-presenting cell activity.
Baadsgaard
O
O
Department of Dermatology, University of Michigan Medical Center, Ann Arbor.
Gupta
A K
AK
Taylor
R S
RS
Ellis
C N
CN
Voorhees
J J
JJ
Cooper
K D
KD
D000938:Antigen-Presenting Cells / Q000502:physiology*; D000945:Antigens, Differentiation, T-Lymphocyte / Q000032:analysis; D002452:Cell Count; D003584:Cytological Techniques; D004817:Epidermis / Q000276:immunology / Q000473:pathology* / Q000503:physiopathology; D006684:HLA-DR Antigens / Q000032:analysis; D006801:Humans; D007519:Isoantigens / Q000276:immunology; D008213:Lymphocyte Activation; D011565:Psoriasis / Q000276:immunology / Q000473:pathology* / Q000503:physiopathology; D013601:T-Lymphocytes / Q000502:physiology
D000945:Antigens, Differentiation, T-Lymphocyte; D006684:HLA-DR Antigens; D007519:Isoantigens