A new study has identified how exposure to sunlight
alleviates symptoms of eczema by triggering the
release of a compound in the skin that dampens
The MRC researchers say their findings pave the way
for new therapies that mimic the effects of the
sun’s rays without its damaging side effects.
People with severe eczema are often prescribed UV
light therapy, using tanning lamps, which can
improve the itchy skin lesions associated with the
However, the UV can have damaging side effects on
their skin, including burning, ageing and raising
their skin cancer risk.
The study, published in the Journal of Allergy and
Clinical Immunology opens in new window, found that
exposing a small patch of skin on healthy volunteers
to UV light triggered nitric oxide to be released
into the blood stream.
Further lab studies found that the chemical
activated specialised immune cells, called
regulatory T cells, which act to dampen the ongoing
inflammatory immune response.
In patients with eczema, the proportion of these
regulatory T cells in their blood following light
therapy directly correlated with disease
Researchers say their findings could lead to new
therapies for eczema, which affects around one in
five children and one in 20 adults in the UK.
Lead researcher Dr Anne Astier, from the MRC Centre
for Inflammation Research at the University of
“Our findings suggest that nitric oxide has powerful
anti-inflammatory properties and could offer an
alternative drug target for people with eczema.
Activating regulatory T cells using this pathway may
also provide a target for developing treatments for
other conditions with overactive immune responses,
including autoimmune diseases and rejection of
Professor Richard Weller, a co-senior author on the
study from the University of Edinburgh Medical
“It is clear that the health benefits of sunlight
stretch far beyond vitamin D and we are starting to
fill in these blank spaces.”
For more information
Nitric oxide induces human CLA+CD25+Foxp3+
regulatory T cells with skin homing potential
The Journal of Allergy and Clinical Immunology
MRC - Medical Research Council