The Differential Effect of Broad Band Vs Narrow Band UVB with Respect to Photodamage and Cutaneous Inflammation

Since Fischer reported on the superiority of 313 nm UVB compared with broad band UVB in the treatment of psoriasis, narrow band UVB has become the main phototherapeutical modality in several countries. There is some discussion about the safety and photobiological effects of narrow band UVB. In the present study, narrow and broad band UVB have been compared with respect to parameters for photodamage and inflammation. Fourteen healthy volunteers were randomized in two groups. Both groups were irradiated with three minimal erythema doses (MED) of narrow or broad brand UVB, respectively. Before and 4, 24 and 48 h after irradiation, 6 mm biopsies were taken from immunohistochemical analysis of p53, apoptosis and p16 (photodamage parameters) and T-cells, polymorphonuclear leukocytes (PMN) and Langerhans' cells (inflammatory cells). Mean MED for narrow band UVB was 8.125 times higher than broad band UVB. Significant changes in expression were seen for all parameters except for p16. P53, apoptosis, T-cells and PMN increased, while Langerhans' cell count decreased significantly. No significant differences were seen between the narrow band UVB. In conclusion, following irradiation of three MED narrow band UVB and broad band UVB safety parameters for carcinogenesis and inflammation were induced to the same extent. As narrow band UVB is more effective than broad band UVB, the present study suggests superiority of narrow band UVB as a treatment with a better benefit risk ration.