Antihistamines may fight cancer

For those of you that suffer from watery, itchy eyes and runny
noses throughout allergy season, antihistamines are likely to be your
best friend. But a new study finds the drugs may do more than combat hay
fever; they could fight cancer, too.

The research team, including Daniel H. Conrad, PhD, of the Department of
Microbiology and Immunology at Virginia Commonwealth University,
recently published their findings in The Journal of Leukocyte Biology.

Antihistamines are medication used to prevent or relieve symptoms of allergies, including hay fever, atopic eczema and reactions from insect bites and hives.
The drugs work by stopping the release of histamine - a substance
produced by the body that causes watery eyes, itching, sneezing, runny
nose and breathing problems.

But the researchers found that as antihistamines do their job, they also
interfere with the function of myeloid-derived suppressor cells - a
type of cell known to hinder the body's ability to combat tumors -
meaning a new cancer drug candidate may be in the cards.

Antihistamines 'reversed tumor-enhancing effects of myeloid-derived suppressor cells'

To reach their findings, the team analyzed two groups of mice. In one
group, the researchers triggered a strong allergic response by infecting
them with a rodent intestinal helminth, while the other group of mice
had tumors.

Could
antihistamines also help fight cancer? Researchers found they reversed
the tumor-enhancing effects of myeloid-derived suppressor cells in mice.

The allergic mice were then injected with myeloid-derived suppressor
cells and treated with one of two antihistamines - cetirizine or
cimetidine. The mice with the tumors were also injected with the cells
but were only treated with the antihistamine cimetidine.

The researchers found that in the allergic mice, the
antihistamines reversed the effects of the myeloid-derived suppressor
cells. However, in the mice with tumors, the antihistamine not only
reversed the effects of the cells, but also reversed the increased tumor
growth that the cells normally trigger.

The team also analyzed the blood of patients with and without allergies.
They found that those with allergies - who usually have a higher
release of histamine - had higher levels of myeloid-derived suppressor
cells circulating in their blood.

According to the researchers, their study shows that antihistamines
should be further investigated as a drug to target myeloid-derived
suppressor cells.

Commenting on the team's findings, John Werry, PhD, deputy editor of The Journal of Leukocyte Biology, says:

"Antihistamines may be one of the most commonly used
over-the-counter drugs, but this report shows that we still have much to
learn about their potential benefits.

It is certainly not yet time to prophylactically administer
antihistamines for cancer prevention, but the more we learn about
myeloid-derived suppressor cells, the more interesting these cells and
their products become as immunotherapy targets in cancer. These new
results suggest that we must be open-minded about seemingly distantly
related immune mechanisms to examine."

It is not only cancer prevention that antihistamines may be useful for. Last year, Medical News Today reported on a study by researchers at the University of Basel in Switzerland, which found that a compound in antihistamines may reduce bad memories.

Written by Honor Whiteman