Asthma and Allergy

February 24, 1997

Johns Hopkins scientists have found the first hard evidence that viral infections can help cause asthma and allergies, a connection long suspected but never directly confirmed in the lab.

Hopkins researchers showed that weak viral infections can cause immune system B cells to produce immunoglobin E or IgE, a protein that orchestrates the reactions that cause allergies and many cases of asthma.

"This suggests we might one day be able to reduce the incidence of allergy and asthma by vaccinating children against mild childhood viral diseases that traditionally haven't received much attention," says Farhad Imani, Ph.D., instructor of medicine, who presents his results at the annual meetings of the American Academy of Allergy, Asthma and Immunology.

"We've suspected that there might be a connection since the late '70s, when studies found that kids who had more viral infections were more likely to have asthma and allergy later in life," says Imani. More recent animal studies have shown that viral infection can increase IgE levels in the blood.

In test tube studies, Imani and his colleagues exposed human B cells, which recognize and attack a particular type of intruder, to rhino and vaccinia viruses. B cells normally attack germs with immunoglobins type M or G (IgM or IgG). Imani found that after viral infections, many of the cells switched to making IgE.

"Basically, if you have a group of B cells that is producing IgE, you're going to be allergic to whatever that group of B cells is sensitive to," Imani explains.

Ironically, stronger viruses capable of causing serious disease were less likely to trigger the switch to IgE than wimpier viruses rapidly defeated by the immune system.

"This appears to be because the weaker viruses activate anti-viral protein kinase, a protein that the B cell uses to defend itself," Imani explains. "This kinase also helps stimulate the start of IgE production in the B cell."

The more sophisticated viruses have found ways to evade the kinase, but many simpler viruses still cannot avoid it.

"These weaker viruses might not cause much suffering during the infection, but they could be causing pain farther down the road by helping the development of allergies."

Imani plans further studies both to determine which viruses will switch on IgE and to flesh out the link between the activation of anti-viral protein kinase and the start of IgE production.

The study was funded by the American Lung Association, the National Institutes of Health, and the Hopkins School of Medicine. Other authors were Kelly Rager, Branimir Catipovic, M.D., Vincenzo Casolaro, M.D., David Proud, Ph.D., J.O. Langland, Ph.D., Bertram Jacobs, Ph.D., and David Marsh, Ph.D.
-end-


Johns Hopkins Medicine

Related Asthma Articles from Brightsurf:

Breastfeeding and risks of allergies and asthma
In an Acta Paediatrica study, exclusive breastfeeding for the first 3 months was linked with a lower risk of respiratory allergies and asthma when children reached 6 years of age.

Researchers make asthma breakthrough
Researchers from Trinity College Dublin have made a breakthrough that may eventually lead to improved therapeutic options for people living with asthma.

Physics vs. asthma
A research team from the MIPT Center for Molecular Mechanisms of Aging and Age-Related Diseases has collaborated with colleagues from the U.S., Canada, France, and Germany to determine the spatial structure of the CysLT1 receptor.

New knowledge on the development of asthma
Researchers at Karolinska Institutet in Sweden have studied which genes are expressed in overactive immune cells in mice with asthma-like inflammation of the airways.

Eating fish may help prevent asthma
A scientist from James Cook University in Australia says an innovative study has revealed new evidence that eating fish can help prevent asthma.

Academic performance of urban children with asthma worse than peers without asthma
A new study published in Annals of Allergy, Asthma and Immunology shows urban children with poorly controlled asthma, particularly those who are ethnic minorities, also suffer academically.

Asthma Controller Step Down Yardstick -- treatment guidance for when asthma improves
The focus for asthma treatment is often stepping up treatment, but clinicians need to know how to step down therapy when symptoms improve.

Asthma management tools improve asthma control and reduce hospital visits
A set of comprehensive asthma management tools helps decrease asthma-related visits to the emergency department, urgent care or hospital and improves patients' asthma control.

Asthma linked to infertility but not among women taking regular asthma preventers
Women with asthma who only use short-acting asthma relievers take longer to become pregnant than other women, according to research published in the European Respiratory Journal.

What are the best ways to diagnose and manage asthma?
A team of experts from The University of Texas Medical Branch at Galveston examined the current information available from many different sources on diagnosing and managing mild to moderate asthma in adults and summarized them.

Read More: Asthma News and Asthma Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.