Photoprotection by thalidomide in patients with chronic cutaneous and systemic lupus erythematosus: discordant effects on minimal erythema dose and sunburn cell formation.

BACKGROUND

Thalidomide is an anti-inflammatory and immunomodulatory agent with proven efficacy in several refractory inflammatory skin conditions including photoexacerbated skin diseases. The effects of thalidomide on ultraviolet (UV)-induced cutaneous damage in humans have not been extensively studied. We describe the results of minimal erythema dose (MED) testing in nonlesional skin of three patients with chronic cutaneous lupus erythematosus (CCLE) before and after treatment with thalidomide.

OBJECTIVES

To determine whether thalidomide treatment provides clinical and histological evidence of photoprotection from acute UV injury.

METHODS

MED testing was performed in nonlesional skin of three patients with CCLE before and after treatment with thalidomide. Skin biopsy specimens were taken from MED sites for in situ immunochemistry.

RESULTS

In each patient, the MED to UVB irradiation was significantly higher while the patient was receiving thalidomide treatment than in the absence of thalidomide, suggesting a systemic photoprotective effect. Thalidomide treatment had no significant effect on markers of apoptosis including sunburn cell formation and terminal deoxynucleotidyl transferase-mediated biotinylated deoxyuridine triphosphate nick end labelling, which identifies single-strand breaks in DNA.

CONCLUSIONS

Thalidomide inhibits acute UVB erythema at 24 h after exposure, as a 100-mg daily dose of this drug for 4 weeks conveyed a sun protection factor of 1.56 to > 4.0. We conclude that inhibition of UVB-induced inflammation may, in part, explain the therapeutic benefits of this agent on photosensitive diseases.