title: High mobility group box1 (HMGB1) in relation to cutaneous inflammation in systemic lupus erythematosus (SLE).
abstract: CONCLUSIONS
  Photosensitivity is characteristic of systemic lupus erythematosus (SLE). Upon ultraviolet B (UVB) exposure, patients develop inflammatory skin lesions in the vicinity of sunburn cells (SBCs). High mobility group box 1 (HMGB1) is released from apoptotic and activated cells and exerts inflammatory actions through ligation to its receptors.
  
  
  METHODS
  Eleven SLE patients and 10 healthy controls (HCs) were exposed to UVB. Skin biopsies were taken before and at one, three and 10 days after irradiation. Sections were stained for SBC, HMGB1, CD3, CD68, interferon-induced protein MxA and cleaved caspase 3. In vitro experiments with UVB-irradiated keratinocytes were also performed. Higher numbers of cells that had released HMGB1 were seen in the skin of SLE patients compared to HCs before and after irradiation. HMGB1-negative nuclei correlated with the presence of SBCs, and with the number of cleaved caspase 3 positive cells in lupus skin.
  
  
  RESULTS
  HMGB1 release is increased in the skin of SLE patients compared to HCs. Upon UVB exposure, HMGB1 release further increases in SLE patients and is related to the number of apoptotic cells. Our data suggest that HMGB1, probably released from apoptotic keratinocytes, contributes to the development of inflammatory lesions in the skin of SLE patients upon UVB exposure.
authors.affiliation: Department of Rheumatology and Clinical Immunology, University Medical Center, University of Groningen, The Netherlands.
authors.forename: D A
authors.initials: DA
authors.lastname: Abdulahad
authors.forename: J
authors.initials: J
authors.lastname: Westra
authors.forename: E
authors.initials: E
authors.lastname: Reefman
authors.forename: E
authors.initials: E
authors.lastname: Zuidersma
authors.forename: J
authors.initials: J
authors.lastname: Bijzet
authors.forename: P C
authors.initials: PC
authors.lastname: Limburg
authors.forename: C G M
authors.initials: CG
authors.lastname: Kallenberg
authors.forename: M
authors.initials: M
authors.lastname: Bijl
mesh_terms: D000328:Adult; D017209:Apoptosis / Q000528:radiation effects; D001706:Biopsy; D016022:Case-Control Studies; D053148:Caspase 3 / Q000378:metabolism; D005260:Female; D024243:HMGB1 Protein / Q000378:metabolism*; D006801:Humans; D007249:Inflammation / Q000175:diagnosis / Q000209:etiology*; D015603:Keratinocytes / Q000378:metabolism / Q000528:radiation effects; D008180:Lupus Erythematosus, Systemic / Q000150:complications*; D008297:Male; D008875:Middle Aged; D010787:Photosensitivity Disorders / Q000175:diagnosis / Q000209:etiology*; D012867:Skin / Q000378:metabolism / Q000473:pathology / Q000528:radiation effects; D013997:Time Factors; D014466:Ultraviolet Rays / Q000009:adverse effects
chemical_list: D024243:HMGB1 Protein; D053148:Caspase 3
keywords: HMGB1; SLE; skin