1. University of Arizona College of Medicine - Phoenix; Phoenix AZ 85004 USA
2. Institute of Environmental Medicine, Karolinska Institutet; SE-171 77 Stockholm Sweden
3. Loma Linda University School of Medicine; Loma Linda CA 92350 USA
4. Department of Dermato-Allergology; Copenhagen University Hospital Gentofte, Niels Andersens Vej 65; DK-2900 Hellerup Denmark