title: The cytotoxic effect of neonatal lupus erythematosus and maternal sera on keratinocyte cultures is complement-dependent and can be augmented by ultraviolet irradiation.
abstract: To elucidate the role of autoantibodies and ultraviolet (UV) exposure in the pathogenesis of the skin lesions in neonatal lupus erythematosus (NLE), keratinocytes were cultured, as the target cells, from a patient with NLE and from a normal neonate. We demonstrated that the expression of nuclear/cytoplasmic Ro/SSA and La/SSB molecules on to the surface of NLE keratinocytes occurred to a much greater extent than that on normal keratinocytes. A dose of 200 mJ/cm2 UVB irradiation on NLE keratinocytes induced a 2.5-3-fold increase in Ro/SSA and La/SSB expression compared to non-irradiated cells. Sera derived from both the NLE patient and from his mother exhibited a cytotoxic effect on NLE keratinocytes, but not on control cells, in the presence of complement. Furthermore, the cytotoxicity of the sera was enhanced on UVB-irradiated NLE keratinocytes, whereas it had no cytotoxic effects on UVB-irradiated control cells. This suggests that the abnormal expression of both Ro/SSA and La/SSB on the surface membrane of NLE keratinocytes induces the autoantibodies and complements to injure the cells. This complement-mediated cytotoxic effect can be augmented by UV irradiation, a concept not incompatible with the exacerbation of the skin eruption in sun-exposed skin sites.
authors.affiliation: Department of Dermatology, Kaohsiung Medical College, Taiwan.
authors.forename: H S
authors.initials: HS
authors.lastname: Yu
authors.forename: L C
authors.initials: LC
authors.lastname: Chiang
authors.forename: C H
authors.initials: CH
authors.lastname: Chang
authors.forename: J W
authors.initials: JW
authors.lastname: Kang
authors.forename: C L
authors.initials: CL
authors.lastname: Yu
mesh_terms: D000954:Antigens, Surface / Q000378:metabolism; D001323:Autoantibodies / Q000009:adverse effects*; D002478:Cells, Cultured; D003165:Complement System Proteins / Q000502:physiology; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D015603:Keratinocytes / Q000378:metabolism / Q000528:radiation effects*; D008178:Lupus Erythematosus, Cutaneous / Q000378:metabolism* / Q000473:pathology / Q000503:physiopathology; D008297:Male; D018811:Maternal Exposure; D014466:Ultraviolet Rays / Q000009:adverse effects
chemical_list: D000954:Antigens, Surface; D001323:Autoantibodies; D003165:Complement System Proteins