WEDNESDAY, Nov. 14 (HealthDay News) -- A protein that may have originally evolved to help protect the airways now appears to be a biomarker that indicates severe asthma. And it may also play a role in the development of asthma, according to new research.

Reporting in the Nov. 15 issue of the New England Journal of Medicine, Yale University researchers said that people with severe asthma were more likely to have elevated levels of the protein known as YKL-40 in their blood compared to people without asthma.

"We believe that it's a marker of the inflammatory response associated with asthma," said the study's lead author, Dr. Geoffrey Chupp, an associate professor of medicine at Yale University School of Medicine. And, he added, "These new novel family of molecules could be very important in asthma pathogenesis. Down the road, there could be new treatments and new ways to characterize asthma."

YKL-40 is what's known as a chitinase-like protein. It attaches itself to chitin, an abundant substance found in fungi, crustaceans and in insects like dust mites and cockroaches. It's also present in the pharynx and eggs of parasitic worms called helminths. Infection with helminths used to be common but is now rare in developed countries, according to the author of an accompanying editorial in the same issue of the journal, Dr. Burton Dickey, chairman of pulmonary medicine at M.D. Anderson Cancer Center in Houston. These worms migrate through the skin into the bloodstream and travel through the lungs to get into the gastrointestinal tract, he said.

Humans don't manufacture chitin but do produce chitinases (enzymes that break down chitin) and chitinase-like enzymes (enzymes that bind to chitin, but don't break it down). The presence of chitin in the lungs may make the body believe that it has a helminth infection that it needs to defend against, Dickey said. Unfortunately, he pointed out, this defense mechanism may now be reacting to harmless dust mites instead.

However, both Dickey and Chupp noted that the new study doesn't prove that YKL-40 is a cause of asthma, only that elevated levels appear to be a marker of severe asthma.

Chupp and his colleagues at Yale, the University of Paris and the University of Wisconsin recruited 253 adults -- some with asthma and some without. Levels of YKL-40 were measured from blood samples at all three study sites. In Paris, the researchers also conducted lung biopsies.

The researchers found that, overall, people with asthma had higher levels of YKL-40 in both blood levels and in lung biopsies than did people without the airway disease. In the Yale group, the average levels of YKL-40 were 49.1 nanograms (ng) per milliliter of blood for people with mild asthma, 58.3 ng per milliliter for controls, 68.4 for those with moderate asthma, and 77 ng per milliliter for those with severe asthma. The findings were similar in both the Paris and the Wisconsin groups, the researchers said.

Chupp pointed out that the one of the biggest potential benefits of the new research is that YKL-40 is easily detected in the blood.

The study's senior author, Dr. Jack Elias, chairman of medicine and a professor of immunobiology at Yale, said in a prepared statement: "This may allow us to identify a subpopulation of patients with severe asthma and give us insights into the biologic processes that make the disease so severe in these individuals.

"Our studies also have demonstrated that eliminating YKL-40 decreases specific types of tissue inflammation, which could be of particular benefit to asthmatic patients with an elevated level of this protein," he added.

Dickey said: "It's always been something of a mystery why asthma prevalence has risen in the 20th century, and this may help us begin to understand it. Chitinase and chitinase-like proteins are a highly effective protective response against worms, and for most of human history, we have been burdened with these parasites. An asthma-like response probably evolved to protect against worms. Now it appears this protective response may have gone awry and something as harmless as dust mites or pollen is initiating it."

Dickey said if chitin truly is triggering an inflammatory airway response that leads to asthma, these findings could open up whole new avenues of research and new therapies.

More information

To learn more about asthma, visit the U.S. National Library of Medicine.

WEDNESDAY, Nov. 14 (HealthDay News) -- Breast-feeding in the first three months of life appears to help shield children from developing food allergies.

That's just one of a number of findings on food allergies scheduled to be presented this week at the annual meeting of the American College of Allergy, Asthma and Immunology in Dallas.

Research has determined a possible role for food allergy prevention strategies in high-risk children, including maternal food avoidance in pregnancy, breast-feeding, maternal food avoidance while breast-feeding, use of hypoallergenic formulas, delayed introduction of allergenic foods and probiotics, noted one expert.

"A review of 18 studies demonstrates a significant protective effect of exclusive breast-feeding for at least three months for children with high risk for atopy (genetic tendency to develop allergic diseases) against the development of atopic dermatitis and early childhood asthma-like symptoms," Dr. Robert Wood, international health director for pediatric allergy and immunology at Johns Hopkins School of Medicine, said in a prepared statement.

He offered a number of recommendations for children at high risk of allergic diseases:

• Women should avoid peanuts and tree nuts during pregnancy and while breast-feeding.
• Mothers should supplement breast-feeding with a hypoallergenic formula (extensively or partially hydrolyzed).
• Delay feeding these children solid foods until they're six months old.
• Delay introduction of milk and egg until age 1 and peanut and tree nuts until age 3.
• Start early intervention when signs of food allergy appear (secondary prevention).

In a planned presentation about allergies and dietary restrictions, another expert noted that a person may have an allergy to one member of a food family, but may be able to eat other members of the same food family.

For example, one study on nine common fish found cross-reactivity and allergenicity were highest among cod, salmon and pollack and lowest among halibut, flounder, tuna and mackerel. Another study on edible nuts found cross-reactivity was strong among walnut, pecan and hazelnut; moderate among cashew, pistachio, Brazil nut and almond; and extremely low between peanut and tree nuts.

"You may be allergic to a particular part of a food, but not to another part," Dr. Sami Bahna, chief of allergy and immunology at Louisiana State University in Shreveport, said in a prepared statement.

Another expert said doctors need to consider food allergy as a potential cause of gastrointestinal or dermatological symptoms in patients.

"The eosinophilic gastrointestinal disorders (EGID) which may affect the esophagus, stomach, colon and rectum are mostly chronic and recurrent disorders that adversely impact quality of life for patients and families," Dr. Amal Assa'ad, director of the Food Allergy & Eosinophilic Disorders Clinic at Cincinnati Children's Medical Center, said in a prepared statement.

"Patients with EGID have a high rate of sensitization to food and environmental allergens, and many of them have a high rate of clinical symptoms with various food ingestions. A subset of patients respond to removal of major food allergens from their diet," Assa'ad said.

"EGID management often requires multiple specialists, including the primary physician, allergy and immunology, gastroenterology, nutrition and psychology," she noted.

More information

The U.S. National Institute of Allergy and Infectious Diseases has more about food allergy.

(HealthDay News) - Pneumonia is a respiratory infection, caused by either bacteria or a virus, that can be acquired on its own, or as a common complication of the flu.

A vaccine is available to combat pneumococcal pneumonia, a type of pneumonia caused by bacteria. Ask your doctor if you are at greater risk of this type of pneumonia, and if you should be vaccinated.

Here are additional ways to help protect yourself from pneumonia, courtesy of the American Lung Association:

• Get a flu vaccine every flu season.
• If you notice respiratory symptoms that last for several days, seek treatment at once.
• Get plenty of sleep, exercise regularly, and maintain a healthy diet.
• If you are taking antibiotics for any bacterial infection, be sure to finish the entire prescription.