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Plasmacytoid dendritic cells are absent in skin lesions of polymorphic light eruption
Author(s) -
Wackernagel Alexandra,
Massone Cesare,
Hoefler Gerald,
Steinbauer Elisabeth,
Kerl Helmut,
Wolf Peter
Publication year - 2007
Publication title -
photodermatology, photoimmunology and photomedicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.736
H-Index - 60
eISSN - 1600-0781
pISSN - 0905-4383
DOI - 10.1111/j.1600-0781.2007.00267.x
Subject(s) - cd68 , pathology , interleukin 3 receptor , dermis , pathogenesis , immunohistochemistry , medicine , psoriasis , immunology , flow cytometry
Background/purpose: Polymorphic light eruption (PLE) is a common photodermatosis of potential autoimmune origin, and an overlap with lupus erythematosus (LE) has been described. Plasmacytoid dendritic cell (PDC)‐induced expression of interferon (IFN)‐α has been found to be present in LE skin lesions and plays a pivotal role in the pathogenesis of LE by promoting autoimmunity. We therefore asked whether PDCs may also be involved in the pathogenesis of PLE and searched for those cells [which can be identified by their high levels of interleukin (IL)‐3 receptor α chain (CD123), combined with other cell markers such as CD68] in skin lesions. Methods: Paraffin‐embedded biopsy specimens from a total of 27 patients with clinically and histologically confirmed PLE (nine women, mean age 32.7 years, age range 18–43), LE (seven women, four men, CCLE: n =4, SCLE: n =2, lupus tumidus: n =5, mean age 48.5 years, age range 41–65) or psoriasis (four women, three men, mean age 43.3 years, age range 19–54) (as control group) were analyzed by immunohistochemical CD68/CD123 double staining. Quantification of the immunohistochemical staining was performed by visual cell counting of CD68−/CD123+, CD68+/123–, and CD68+/CD123+ cells separately in the epidermis and dermis of the samples in at least 10 random fields per sample at × 400 microscopic magnification by two of the investigators in a blinded fashion. Results: Microscopic examination of the immunohistochemically stained sections revealed that CD68+/CD123+ cells were present in most specimens obtained from LE [10/11 (91%)] and psoriasis [6/7 (86%)] patients but not at all in those obtained from PLE patients. Quantification and statistical analysis of the dermal infiltrate revealed that CD68+/CD123+ cells were present at a mean±SEM field density of 5.6±1.3 in LE, 1.6±0.6 in psoriasis but totally absent in PLE ( P =0.0010 vs. LE, P =0.0135 vs. psoriasis by an unpaired Student's t ‐test). Conclusion: The results confirm the potential significance of PDCs in LE and psoriasis, however the absence of PDCs in PLE contradicts the hypothesis that these cells might play a role in the latter disease.