- Epidermal H(2)O(2) accumulation alters tetrahydrobiopterin (6BH4) recycling in vitiligo: identification of a general mechanism in regulation of all 6BH4-dependent processes? Schallreuter, K.U., Moore, J., Wood, J.M., Beazley, W.D., Peters, E.M., Marles, L.K., Behrens-Williams, S.C., Dummer, R., Blau, N., Thöny, B. J. Invest. Dermatol. (2001)