Contribution of Skin Color in Stabilization of Active Cases of Vitiligo by Narrow Band UVB

The Reflection of Skin Color on the Efficacy of Narrow Band UVB in Stabilization of Active Cases of Vitiligo

Vitiligo is a disease in which autoimmunity plays a major role. Multiple treatment options are available, of which narrow-band UVB is a cornerstone, acting through immunosuppression and repigmentation by stimulating reservoir melanocytes. It's expected that this immunsupression is lower in darker skin types, where increased basal melanin might act as a barrier.

Vitiligo is acquired depigmentation disorder. Several theories were hypothesized for causing vitiligo, of which the autoimmune theory is the most accepted. The main targets of therapy are stabilization of the disease activity through immunosuppression, and repigmentation through stimulation of reservoir melanocytes proliferation and migration. Narrow band ultraviolet phototherapy (NB-UVB) remains the cornerstone treatment of vitiligo. NB-UVB can induce both immunosuppression and repigmentation. Several factors can modulate the efficacy of NB-UVB therapy in treatment of vitiligo cases, including patient's age, lesion site, duration of the disease, and duration of the therapy. The immunosuppressive function of NB-UVB was first detected in 1963 by Hanisko and Suskind, who observed that the contact hypersensitivity response in skin sensitized to dinitrochlorobenzene (DNCB) was reduced if skin was previously exposed to suberythemal doses of UVB. Present evidence suggests that UVB suppress immune system through generation of T-suppressor cells, which inhibit the effector cells of Th1 type. It appears that UV-induced immunosuppression depresses the function of Th1 cells and enhances the activity of Th2 cells via cytokines such as Interleukin 10. It's expected that this immunsupression is lower in darker skin types, where increased basal melanin might act as a barrier. However, skin was previously divided to UVB-resistant and UVB-sensitive (UVB-R and UVB-S) based on the contact hypersensitivity testing, regardless of the skin type. Moreover, A study on NB-UVB phototherapy for psoriasis revealed that photoadaptation during NB-UVB therapy Is Independent of skin type.

100 patients with non-segmental vitiligo are randomized to either NB-UVB therapy with placebo versus NB-UVB combined with mini-oral pulse steroids therapy. Vitligo activity will be assessed according to the VIDA scoring system. Skin type, extent of vitiligo using VES score, photography of all areas according to the VES areas at a fixed distance of 50 cm from the patient, and using a 1 cm diameter circular white sticker for reference later will be done. All patients will receive NB-UVB phototherapy at starting dose of 0.3 J/cm2, 3 times per week for 6 months (72 sessions) with gradually increasing increments according until faint erythema is attained at which point the dose is fixed. 100 patients will be randomized into 2 groups; 50 patients will receive mini pulse dexamethasone therapy in a dose of 3 mg/ day for adults or 1.5 mg/day for children on two consecutive days per week while the other 50 patients will receive placebo having the same color, form and packaging for 6 months.

Masking involves only oral therapy; 100 patients will be randomized into 2 groups; 50 patients will receive mini pulse dexamethasone therapy in a dose of 3 mg/ day for adults or 1.5 mg/day for children on two consecutive days per week while the other 50 patients will receive placebo having the same color, form and packaging for 6 months. The investigators are blinded.

50 patients will receive mini pulse dexamethasone therapy in a dose of 3 mg/ day for adults or 1.5 mg/day for children on two consecutive days per week plus NB-UVB phototherapy at starting dose of 0.3 J/cm2, at a rate of 3 times per week for 6 months (72 sessions) with gradually increasing increments.

50 patients will receive placebo having the same color, form and packaging as the dexamethasone therapy for 6 months plus NB-UVB phototherapy at starting dose of 0.3 J/cm2, at a rate of 3 times per week for 6 months (72 sessions) with gradually increasing increments.

50 patients will receive mini pulse dexamethasone therapy in a dose of 3 mg/ day for adults or 1.5 mg/day for children on two consecutive days per week plus NB-UVB phototherapy at starting dose of 0.3 J/cm2, at a rate of 3 times per week for 6 months (72 sessions) with gradually increasing increments.

50 patients will receive placebo having the same color, form and packaging as the dexamethasone therapy for 6 months plus NB-UVB phototherapy at starting dose of 0.3 J/cm2, at a rate of 3 times per week for 6 months (72 sessions) with gradually increasing increments

A 5 cc blood sample will be withdrawn from each patient for: PCR assessment of m-RNA of CXCL-10 as markers of disease activity.

Inclusion Criteria: Active cases of non-segmental vitiligo, VIDA +2 or more. All skin types Age above 6 years, both sexes. Exclusion Criteria: Contraindications to NB-UVB ( photosensitive skin disorders, skin malignancy, patients on photosensitizing medications) Contraindications to mini-pulse steroid therapy (uncontrolled diabetes or hypertension, peptic ulcer) Stable disease (VIDA 0 & -1) and activity more than 6 months ago (VIDA +1). The use of other treatment for vitiligo during the 3 months previous to enrollment.

Methodology and outcome of the study is palnned to be published in an international medical journal with sharing participants data.