Allergy Not Associated with Development of Non-Hodgkin Lymphoma

Allergies and allergy-related conditions are not likely related to
non-Hodgkin lymphoma risk, according to a new study. Some previous
studies had suggested that allergies might protect against this
cancer.

The body's allergic reaction to a substance includes an increase in
specific types of immune cells. Some researchers have observed a
possible association between allergies and reduced cancer risk and
suggested that the allergy-induced immune response also might inhibit
tumor growth. Non-Hodgkin lymphoma, a cancer of the immune system, is
particularly sensitive to immune system changes, and earlier studies
reported a decreased risk of this cancer among people with allergic
rhinitis, hay fever, or food allergies. However, several other
studies found no such association.

Mads Melbye, M.D., Ph.D., of the Statens Serum Institut in
Copenhagen, and colleagues decided to investigate the relationship
more thoroughly. First they looked at a retrospective study of 3,055
patients with non-Hodgkin lymphoma and 3,187 control patients without
the disease. Questionnaire data and blood samples were collected
after people were diagnosed with non-Hodgkin lymphoma.

Initially they found that people who had ever had hay fever had a
reduced risk of non-Hodgkin lymphoma. Specifically, people with high
levels of the antibodies specific for hay fever had a 32 percent
lower risk of NHL than people who didn't have hay fever. However,
further investigation revealed that among patients with cancer, the
more the cancer had spread throughout the body, the lower the
antibody levels were. This suggested to the researchers that allergic
responses might be dampened by having non-Hodgkin lymphoma.

"Our finding of a lower prevalence of allergic rhinitis among case
patients with non-Hodgkin lymphoma than among population control
subjects may reflect a recent decline in clinical manifestations of
allergic conditions as a result of underlying non-Hodgkin lymphoma
disease," the authors write.

The authors then studied the association in a prospective case-
control population; blood samples were available for 198 lymphoma
patients before they developed their cancer and for 594 control
patients. When they looked at antibody levels in people before they
developed cancer, they found that there was no association between
allergy and the development of non-Hodgkin lymphoma.

"Allergy may not be causally associated with the risk of non-Hodgkin
lymphoma. The inverse association observed in some case-control
studies may arise because non-Hodgkin lymphoma suppresses the
immunologic response to allergens," the authors write.

Contact: Mads Melbye, M.D., Ph.D., Statens Serum Institut,
Copenhagen, +45-32683163 or +45-40111185, mme@...

http://www.eurekalert.org/pub_releases/2007-01/jotn-oh011107.php