The recent article "UV-B Phototherapy Clears Psoriasis Through Local Effects" by Dawe and colleagues1 contained fascinating data and an intriguing conclusion that further invigorates the debate on whether narrowband TL-01 UV-B phototherapy has important systemic effects.
The investigators examined the reduction in psoriatic activity (assessed using the scaling, erythema, and induration [SEI] scoring system) in individual plaques that were either covered during the thrice-weekly TL-01 phototherapy regimen, exposed once a week or exposed 3 times a week with the rest of the body. These treatments continued until the patients were completely clear of psoriasis or had "minimal residual activity." At this point the SEI score of the thrice-weekly treated plaques had dropped by a mean of 7.6 SEI units. If this is considered a near 100% clinical response, it is notable that the unexposed plaques showed a mean clinical improvement (of 3.2 SEI units), equivalent to 42% of this maximal response (it is assumed that the SEI scoring system is linear with disease activity).
Gibbs NK. Narrowband UV-B Phototherapy Clears Psoriasis Through a Combination of Local and Systemic Effects. Arch Dermatol. 2003;139(5):665. doi:10.1001/archderm.139.5.665-a