P7.86 CD4⁺ killer T cells are involved in the alopecia areata

Akira Mukuno¹, Hiromi Tsuboi², Takao Fujimura¹, Yuko Hamada and Kensei Katsuoka¹

1 Department of Dermatology, Kitasato University School of Medicine, Sagamihara, Japan, 2 National Yokohama Medical Center, Yokohama, Japan

Objectives: CD4⁺ killer T cell is the cytotoxic T cell characterized by MHC class II restriction and by induction of target cell apoptosis mediated by Fas-Fas ligand. In this study, we attempted to determine whether the CD4⁺ killer T cell is an effecter cell in alopecia or not, using alopecia areata and normal human skin specimens.

Methods: Skin biopsy specimens were obtained after informed consent from patients with acute phase alopecia areata. The anti CD4 and anti Fas ligand monoclonal antibodies were used this experiment. The biopsy specimens were examined with Zeiss LSM confocal laser scanning microscope fitted with krypton and argon lasers. Sections were illuminated with 488 and 568 nm of light after filtering through an acoustic optical device.

Results and Conclusion: CD4 and Fas ligand double positive cells were detected in alopecia areata lesions. These data suggest that the CD4⁺ killer T cell is an effector cell which causes hair bulb injury, triggering the alopecia areata.