Ultraviolet-A1 (340-400 nm) irradiation therapy in systemic lupus erythematosus

Abstract

Ultraviolet-A1 (UV-A1) wavelengths have been found effective in mitigating signs and symptoms of disease activity in systemic lupus erythematosus (SLE) but studies have been uncontrolled. To rigorously assess the effectiveness and safety of daily low-dose UV-A1 irradiation as a therapeutic agent in this disorder we enrolled 26 women with SLE in an 18-week two-phase study. During the initial six-week prospective, double-blind, placebo-controlled phase, the patients were divided into two groups; Group A was exposed to 60kJ/m2 of UV-A1 (340-400 nm) irradiation within a sunbed five days a week for three weeks and Group B was exposed for an equal amount of time to visible light of greater than > 430 nm (placebo). Each group was then crossed over for exposure to the other source for three weeks. During the second phase-2 weeks-patients and physicians were unblinded and patients were irradiated with progressively decreasing levels of UV-A1 only. Twenty-five patients completed the six-week placebo-controlled phase of the study and eighteen patients participated for the entire 18 weeks. In Group A the systemic lupus activity measure (SLAM) score improved significantly after three weeks of five-day-a-week UV-A1 irradiation (P < 0.05), regressing to baseline during the three weeks of placebo irradiation. Improvement recurred and progressed with six weeks of three-day-a-week UV-A1 irradiation (P < 0.05). Group B patients responded negligibly to the three weeks of visible light, more sharply to UV-A1, and as with Group A, maximally to the six weeks of three-day-a-week UV-A1 (P < 0.01). With twice- and then once-weekly UV-A1 irradiation the SLAM scores worsened slightly. All patients decreased their drug use. Anti-double-stranded DNA antibodies (anti-dsDNA) decreased significantly (P < 0.05) and anti-nuclear antibodies non-significantly. Side effects were negligible. Visible light had no significant effect. In conclusion, low-dose UV-A1 irradiation effectively, comfortably, and without apparent toxicity diminished signs and symptoms of disease activity in SLE.