[The cytotoxic effect of anti-Ro- (SS-A) antibodies and UVA light on human endothelial cells in vitro].

There is in photosensitive lupus erythematosus a strong association of high titers of anti-Ro(SS-A) antibodies in the serum of the patient with the development of special skin reactions depending on UV-light. The aim of our experiments was to detect a cytotoxic effect of anti-Ro(SS-A) antibodies and UVA-light on human endothelial cells in vitro (standard trypan blue exclusion test, SEM). After UVA-doses of 1 to 100 J/cm2, which were tested, and influence of serum containing anti-Ro(SS-A) antibodies (62 E, ELISA) membrane destructions of endothelial cells depending on the UVA-dose can be seen, irrespective of the fact whether the antibodies are present throughout the irradiation or added afterwards. This cytotoxic reaction depends on complement. A UVA-dose of 100 J/cm2 causes lethal damage of 40% of the cells. These results were confirmed by scanning electron microscopy.