title: Occurrence of neutrophils and activated Th1 cells in UVB-induced erythema.
abstract: We investigated the sequential changes in infiltrating inflammatory cells and several cytokine levels over a period of 48 h in human back skin exposed to 3 minimal erythematous doses of UVB. The measurement of blood flow, using a laser Doppler method, indicated that UVB-induced erythema reached a peak 12-24 h after irradiation. Immunohistochemically, an increase in the number of CD4+ T cells was observed in perivascular areas 6 h after the UVB treatment and continued for up to 48 h. CD8+ T cells were scarce until 24 h, but their numbers gradually increased thereafter. HLA-DR+ cells were detected perivascularly and interstitially in parallel with the pattern of CD4+ T-cell infiltration. In contrast, neutrophils were found 3 h after UVB exposure and reached a peak at 24 h. Using a RT-PCR method, we demonstrated that mRNAs for the Th1 cytokines (interferon-gamma and interleukin-2), together with a proinflammatory cytokine (interleukin-8), became detectable at 6 h, whereas mRNA for the Th2 cytokine (interleukin-4) was not found at all during the first 48 h. In contrast, we found an increase in mRNA levels for C3 and tumor necrosis factor-alpha even at 3 h, suggesting a relationship between complement activation and accumulating neutrophils. Our results suggest that neutrophils and CD4+ T cells in UVB-induced inflammation play different roles: neutrophils are more closely related to UVB-induced erythema, while T cells appear to be involved in subsequent dermal and epidermal inflammation accompanied by epidermal hyperproliferation.
authors: Department of Dermatology, Tohoku University School of Medicine, Sendai, Japan. terui@mail.cc.tohoku.ac.jp
authors: T
authors: T
authors: Terui
authors: K
authors: K
authors: Takahashi
authors: M
authors: M
authors: Funayama
authors: A
authors: A
authors: Terunuma
authors: M
authors: M
authors: Ozawa
authors: S
authors: S
authors: Sasai
authors: H
authors: H
authors: Tagami
mesh_terms: D001483:Base Sequence; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology / Q000502:physiology; D046508:Culture Techniques; D004890:Erythema / Q000276:immunology* / Q000473:pathology*; D006801:Humans; D007150:Immunohistochemistry; D018836:Inflammation Mediators / Q000032:analysis*; D008969:Molecular Sequence Data; D009504:Neutrophils / Q000502:physiology*; D012333:RNA, Messenger / Q000032:analysis*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012680:Sensitivity and Specificity; D012867:Skin / Q000528:radiation effects; D018417:Th1 Cells / Q000276:immunology / Q000502:physiology*; D018418:Th2 Cells / Q000276:immunology / Q000502:physiology*; D018608:Ultrasonography, Doppler; D014466:Ultraviolet Rays / Q000009:adverse effects; D015854:Up-Regulation
chemical_list: D018836:Inflammation Mediators; D012333:RNA, Messenger