Antibodies to UV DNA and photosensitivity.

Antibodies to ultraviolet light denatured DNA (UV DNA) have been measured in the sera of patients with systemic lupus erythematosus, discoid lupus erythematosus, and light sensitive skin lesions. Antibodies were found in significant levels in the patients with SLE but not in the other groups. It appears that although UV denaturation of dermal DNA occurs in vivo this is not sufficient to induce antibodies to UV DNA in patients with a normal DNA repair mechanism. This may not be the case in patients with SLE in whom a break in tolerance to Native (N-) DNA has already occurred and where antibody to N-DNA will cross react with UV DNA.