Thesis (Ph.D.) - Cairo University - National Institute of Laser Enhanced Sciences - Department of Laser Applications in Medical and Biological

Background: The 308-nm monochromatic Excimer light (MEL) may present some advantages as compared tonarrow band ultra-violet B(NBUVB) for the treatment of vitiligo. To the best of our knowledge, no studies compared the histopathological changes of vitiligo lesions before and after treatment by MEL and NBUVB. Aim: To compare the early effects of NBUVBphototherapy and 308-nm MEL in vitiligo patients histopathologically andimmunohistochemically. Patients and Methods: Thirty patients with non-segmental vitiligo were enrolled in this study. Vitiligo lesions were treated twice weekly for 6 weeks with 308-nm MEL, while NB-UVB phototherapy was used to treat lesions contra laterally. Skin biopsies were taken from lesional areas before and after 6 weeks of phototherapy by either modality for histopathological study withHaematoxylin & Eosin (H&E) and immunohistochemically using Human Melanoma Black-45 (HMB-45) stain. Results:Immunohistochemistry findings: All lesions before treatment had labeling index forHMB-45 stain (number of pigmented cells / non pigmented cells) of 0.0(0%). After treatment the LI for MEL was 4.2±2.6 while for NB UVB LI was 0.3±0.7. H&E findings: MEL showed higher statistical significance regarding increase of basal pigmented cells, and significant decrease in vacuolated keratinocytes and basal membrane thickness than NBUVB. Conclusions:Although NBUVB is a standard treatment option for vitiligo, MEL is recognized as an effective vitiligo treatment that induces more repigmentation than NB-UVB, and more rapidly, as this was confirmed by our study

Issued also as CD