According to co-investigator Richard L. Gallo, MD, PhD, a dermatologist at the Veterans Affairs (VA) San Diego Health Care System and the University of California, San Diego, the finding may also lead to safer testing to identify those who should not receive the vaccine.
"Understanding the role of natural human antibiotics in diseases such as atopic dermatitis gives us a window into the possible reasons behind susceptibility to infections, and may help us better predict and control reactions to the smallpox vaccine or similar agents," said Gallo.
Gallo collaborated with a team at the National Jewish Medical and Research Center and Colorado Health Sciences Center that included lead investigator Michael D. Howell, PhD, and senior author Donald Y. M. Leung, MD, PhD.
In experiments in test tubes and mice, the researchers found that a germ-killing peptide called LL-37--largely absent from the skin of those with atopic dermatitis--selectively kills vaccinia, the living virus in the smallpox vaccine. The virus is a relatively benign cousin of variola, the virus in smallpox. The researchers believe LL-37 may be a key part of the normal immune response that allows vaccinia to confer immunity for smallpox but stops it before it can replicate and cause harm.
In 2002, a team including Gallo and Leung reported that people with atopic dermatitis (AD) are prone to recurring skin infections because they fail to produce germ-killing peptides known as beta-defensins and cathelicidins. These include "antimicrobial cathelicid
Contact: Cindy Butler
VA Research Communications Service