The cytotoxic effect of neonatal lupus erythematosus and maternal sera on keratinocyte cultures is complement-dependent and can be augmented by ultraviolet irradiation.
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.
Yu
H S
HS
Department of Dermatology, Kaohsiung Medical College, Taiwan.
Chiang
L C
LC
Chang
C H
CH
Kang
J W
JW
Yu
C L
CL
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
D000954:Antigens, Surface; D001323:Autoantibodies; D003165:Complement System Proteins