Dr. Johnson's Allergy Update » Immunology

Ways to improve indoor air quality

jen — Fri, 30 Sep 2011 18:40:02 +0000

Keep a relative humidity of 30-50 percent. This helps reduce mold and dust mites, which die when the humidity is below 40 percent, according to the American College of Allergy, Asthma & Immunology.

Be cautious of products marketed to “clean” the air, like sprays and plug-in fresheners that release particles.

While room-sized air cleaners can reduce airborne allergens, they can generate ozone – a gas regulated by the EPA as a lung irritant in outdoor air, says Dr. Julie McNairn, an allergist and immunologist with Premier Allergy and Asthma Associates in Middletown. Look for models with the Asthma and Allergy Foundation of America’s “asthma & allergy friendly” certification (www.asthmaandallergyfriendly.com), which indicates they can reduce allergen levels by more than 75 percent and do not contribute to ozone levels in the home that exceed federal regulations.

Use bathroom and kitchen exhaust fans that vent outdoors.

Use natural ingredients for cleaning, like baking soda and vinegar, McNairn recommends, or buy products with the cleaning solution already infused into a cloth.

Use a dehumidifier to reduce the potential of mold growth in a damp basement.

If cleaning up mold – areas less than about 10 square feet can be handled without professional help, according to EPA recommendations – use bleach, not soap. Some types can serve as a food source for mold, McNairn says.

Run the fan in a central air system even when the heat and air conditioning are not on.

http://news.cincinnati.com/apps/pbcs.dll/article?AID=201010210326

Three ways to fight mold at home

jen — Wed, 21 Sep 2011 19:36:03 +0000

Most people know that heavy rains and water leaks can lead to mold and mildew problems at home. But what do you do when the worst happens?

Glad you asked. September is National Mold Awareness Month, and the non-profit Allergy & Asthma Network Mothers of Asthmatics recommends consumers be vigilant about preventing mold, dealing with it immediately after it occurs and to choose cleaning products wisely.

“Mold represents a health risk, especially for the approximately 50 million people in the U.S. affected by allergies,” said Nancy Sander, president of AANMA, in a press release. “Bleach and other toxic cleaners commonly advertised to kill mold spores are airway irritants known to trigger asthma and upper respiratory symptoms. We always encourage families to choose non-toxic options because they work.”

“Mold is a serious issue … Mold thrives in moisture, and in addition to the excess water from storms, … high humidity helps promote mold growth,” said Eric Green, president of Planet People, the manufacturer of Concrobium Mold Control, an EPA-registered, 2-in-1 solution that eliminates mold and prevents it from returning, with zero bleach, ammonia or harmful chemicals.

Experts recommend the following:

Detect it: To prevent mold you must stop water from getting inside your home. Keep an eye out for leaking roofs, cracked foundations, clogged drains and faulty plumbing. Regularly check around kitchen and bathroom sinks, refrigerators and attics.

Dry it: Invest in a shop vacuum or water pump, which also can be rented from a local home improvement store, that you can use to remove water in the event of sudden flooding. Once water is removed, use fans to dry out areas; open doors and windows if possible, as well as closet and cabinet doors to help allow air to circulate.

Ditch it: Don’t be reluctant to throw out water and mold-damaged items that are replaceable. If in doubt, throw it out, including carpeting, padding and ceiling tiles. If drywall has absorbed water, cut out 12 inches above the water level and replace once the room is dried out.

http://www.kansascity.com/2011/09/19/3151983/three-ways-to-fight-mold-at-home.html#ixzz1YVvBuYUX

Researchers Identify Gene Pivotal For Immune System Balance

jen — Thu, 21 Jul 2011 20:12:09 +0000

A team led by St. Jude researchers identified a gene pivotal for immune system balance. Ultimately, the discovery may aid efforts to tame allergies and asthma.

Named Mina, the gene is part of a signaling pathway that may provide novel targets for new treatments and provide further insights into the disease-fighting immune system, explained Mark Bix, Ph.D., Immunology. Bix is senior author of the paper published in Nature Immunology.

A healthy immune system requires balance. Bix is focused on the balance of two specialized cells in one branch of the immune system. The cells are called T-helper type 1 (Th1) and T-helper type 2 (Th2). They arise from a pool of immune cells known as naïve T-helper cells that are arrested at a preliminary stage of differentiation where they are poised for a final differentiation step. During that step they are supposed to acquire specialized immune functions optimized for the control of eliciting pathogens. Chemical messengers known as cytokines control the development of naïve T-helper cells into a variety of more specialized cells, including the Th1 or Th2 cells.

That’s where Mina comes in. Researchers reported this gene works indirectly by regulating production of interleukin 4 (IL-4), a cytokine that plays a central role in balancing Th1 and Th2 cells. Using classical genetics and molecular techniques, investigators showed that Mina dampened IL-4 production by binding to a region of DNA known as the IL-4 promoter. The promoter is where IL-4 production begins. Mice that made large amounts of the Mina protein had low IL-4 levels. When Mina was eliminated, production of the cytokine jumped.

Researchers used a variety of tests involving mouse strains that made different levels of IL-4 to show the rise and fall of IL-4 indirectly controlled Th2 production. High levels of IL-4 favor production of Th2 rather than Th1.

The findings come more than a decade after Bix, then a postdoctoral fellow, started looking for why certain mouse strains mounted an immune response that favored production of either Th1 or Th2 cells. Certain diseases are characterized by an imbalance between those cells.

An imbalance favoring Th2 cells, known as Th2 bias, is linked to an increased risk of problems like allergies and asthma. Th2 cells cause the inflammation that is a hallmark of asthma. Th2 bias is also associated with increased susceptibility to the parasitic infection leishmaniasis, which remains a threat in regions around the equator.

Earlier research from Bix’s laboratory tracked Th2 bias to a region of DNA on chromosome 16 known as Dice1.2. In this study, investigators used a variety of tests to sort through 92 known or predicted genes within Dice1.2 and pinpoint Mina as a key regulator of IL-4.

IL-4 relies on a positive feedback mechanism to influence Th2 production. Newly activated T-helper cells make a small amount of IL-4. The IL-4 then returns through a pathway that includes the IL-4 receptor and transcription factors STAT6 and GATA-3 to entice more T-helper cells to become Th2 rather than Th1 cells. The new Th2 cells respond by secreting even more IL-4.

Bix described Mina as a molecular handle scientists can use to grasp the rest of the new pathway, whose other elements Bix described as links in a chain. “Each one of those links, including the gene we discovered, constitutes a novel target for therapeutic interventions that could help either promote or diminish development toward the Th2 fate,” he explained.

In this study, Bix and his colleagues also proposed a reason for the wide variation in Th2 bias between different mouse strains. The researchers pointed to a region of DNA that included the Mina promoter. They decoded the same region in five different mouse strains. Two favored Th2 production and three did not. The scientists eventually linked the differences to 21 single nucleotide polymorphisms (SNPs). SNPs are relatively common variations in the makeup of particular genes. Those SNPs distinguished mice with high numbers of Th2 cells from those with less Th2 bias. The researchers noted the same DNA region might contain other genomic variations that explain differences in Mina activity.

Mina belongs to a particular family of genes known as transcription factors. Cells use transcription factors to help carry out the instructions genes carry. Mina first surfaced in 2002 in connection with human cancer. Those earlier studies suggested Mina was a target of the Myc oncogene, or cancer gene. However, in T helper cells, Bix’s group found no evidence linking Mina expression with Myc activity.

Other questions remain. Mina lacks an obvious location for binding to the IL-4 promoter. Researchers believe another transcription factor, named NFAT, plays a role in the hookup. They noted the Dice1.2 region of chromosome 16 where Mina was found might contain other genes that contribute to Th2 balance. Mina’s role in response to a Leishmania major infection also remains unclear. Earlier research linked response to the infection to the same DNA region where Mina was found. Researchers speculated Mina might also be the foundation of that response. Other St. Jude authors of the paper are Melanie Van Stry, PhD, and Linda Chung, both of Immunology; and Madoka Koyanagi, PhD, formerly of St. Jude. The research was supported in part by the Cancer Research Institute, the Burroughs Wellcome Fund, the National Institutes of Health and ALSAC.

St. Jude Children’s Research Hospital

St. Jude Children’s Research Hospital is internationally recognized for its pioneering research and treatment of children with cancer and other catastrophic diseases. Ranked the No. 1 pediatric cancer hospital by Parents magazine, St. Jude is the first and only National Cancer Institute-designated Comprehensive Cancer Center devoted solely to children, and has treated children from all 50 states and from around the world. St. Jude has developed research protocols that helped push overall survival rates for childhood cancer from less than 20 percent when the hospital opened to almost 80 percent today. St. Jude is the national coordinating center for the Pediatric Brain Tumor Consortium and the Childhood Cancer Survivor Study. In addition to pediatric cancer research, St. Jude is also a leader in sickle cell disease research and is a globally prominent research center for influenza.

Founded in 1962 by the late entertainer Danny Thomas, St. Jude freely shares its discoveries with scientific and medical communities around the world, publishing more research articles than any other pediatric cancer research center in the United States. St. Jude treats more than 5,400 patients each year and is the only pediatric cancer research center where families never pay for treatment not covered by insurance. St. Jude is financially supported by thousands of individual donors, organizations and corporations without which the hospital’s work would not be possible. In 2010, St. Jude was ranked the most trusted charity in the nation in a public survey conducted by Harris Interactive, a highly respected international polling and research firm.

http://www.medicalnewstoday.com/articles/185028.php

Don’t Just Eat Dirt, Breathe Dirt!

jen — Wed, 13 Apr 2011 16:06:20 +0000

Colonization with a variety of microbes from early childhood appears to be important for balanced immunologic development,

Studies have shown that growing up on a farm is associated with reduced risk for asthma, possibly through stimulation of the innate immune system in early life. These data are supportive of the so-called hygiene hypothesis.

Recently, researchers in Germany analyzed data from two large cross-sectional studies comparing microbial exposures of farm-dwelling and non–farm-dwelling children in central Europe.

In the PARSIFAL study (6843 participants), researchers analyzed mattress dust samples for environmental bacteria via DNA signatures, which detect bacteria that cannot be measured by culture. In the GABRIELA study (9668 participants), researchers used culture techniques to evaluate bacterial and fungal taxa in dust from children’s rooms. Both studies showed that farm-dwelling children had a lower incidence of asthma and atopy and were exposed to a larger variety of environmental microorganisms than non–farm-dwellers. Microbial diversity was inversely related to asthma risk. An inverse relationship was seen between asthma incidence rates and exposure to certain fungal and bacterial species.

Atopy, also significantly less prevalent among farm-dwelling children, was only weakly affected by microbial diversity.

http://dermatology.jwatch.org/cgi/content/full/2011/401/1

Bee pollen superfood boosts immune system function

nicole — Tue, 18 Jan 2011 21:24:36 +0000

There are many superfoods that boost immune function, but few do it with as much potency as bee pollen. Through its unique combination of minerals, vitamins, amino acids and enzymes, bee pollen offers one of the most revitalizing natural superfoods in the world (especially when collected from local bees who are in tune with your local environment).
We’ve put together a collection of research for you here, describing the health benefits of bee pollen. NaturalNews reminds everyone to be mindful when consuming bee products due to the very high stresses already placed on honeybees in North America and Europe. Make sure your source practices organic bee farming and does not expose honeybees to high-fructose corn syrup or other chemicals that may be harmful to bee populations.

Bee pollen and your immune system

Bee pollen has been used throughout history as a superfood to restore energy and recuperative powers to the ailing individual. Bee pollen improves allergies in many individuals, and hence may have a regulating effect on the immune system by helping to dampen unnecessary autoimmune attacks which saves immune warriors for the real cancer battle. There is no toxicity to bee pollen. Other bee products with extraordinary healing properties include royal bee jelly and propolis, which is the antibiotic compound used by bees to disinfect their hives before occupation.
- Beating Cancer with Nutrition by Patrick Quillin, PhD,RD,CNS

While the effects are not so dramatic for everyone with arthritis, bee pollen is used by natural healthcare practitioners around the world to help alleviate arthritis symptoms. Energy Boost: Bee pollen is a popular supplement among many athletes, who report that it helps them train hard and recover quickly. Many athletes report that it helps increase stamina. Immune Support: Bee pollen is reported to help strengthen the immune system. People susceptible to reoccurring colds and respiratory tract infections may be helped.
- The Natural Physician’s Healing Therapies by Mark Stengler, N.D.

http://www.naturalnews.com/027566_bee_pollen_immune_system.html

Bee pollen superfood boosts immune system function

nicole — Tue, 10 Aug 2010 16:13:23 +0000

We’ve put together a collection of research for you here, describing the health benefits of bee pollen. NaturalNews reminds everyone to be mindful when consuming bee products due to the very high stresses already placed on honeybees in North America and Europe. Make sure your source practices organic bee farming and does not expose honeybees to high-fructose corn syrup or other chemicals that may be harmful to bee populations.

Bee pollen has more amino acids and vitamins than other amino-acid-containing products like beef, eggs, or cheese. Bee pollen is one of the few vegetable sources of vitamin B12 (Scheer 1992). A tablespoonful of bee pollen contains about 45 calories and is 15% lecithin (which is required for normal fat metabolism) by weight (Kamen 1991).
- PDR for Herbal Medicines, Fourth Edition by Thomson Healthcare, Inc.

Bee pollen’s natural phenylalanine content acts as an appetite suppressant. Bee pollen helps build the immune system and provides energy for the entire body. It contains 35% protein, 55% carbohydrate, 2% fatty acids and 3% minerals and vitamins. It is high in B-complex and vitamins A, C, D and E and contains lecithin. Where to buy it: Health food stores, in the refrigerated section. Bee pollen is actually many small granules similar to the size of a grain of wheat or quinoa and is usually sold in a plastic container.
- Get Balanced-the Natural Way to Better Health with Superfoods by Jan Lovejoy

Like other bee products, bee pollen has an antimicrobial effect. In addition, it is useful for combating fatigue, depression, cancer, and colon disorders. It is also helpful for people with allergies because it strengthens the immune system. It is best to obtain bee pollen from a local source, as this increases its antiallergenic properties. Fresh bee pollen should not cling together or form clumps, and it should be sold in a tightly sealed container. Some people (an estimated 0.05 percent of the population) may be allergic to bee pollen.
- Prescription for Nutritional Healing, 4th Edition: A Practical A-to-Z Reference to Drug-Free Remedies Using Vitamins, Minerals, Herbs & Food Supplements by Phyllis A. Balch, CNC

The human consumption of bee pollen dates back to antiquity; it was frequently used in the Olympic games in ancient Greece. Today bee pollen is gaining increasing popularity as effective protection against many of the common pollutants in the environment, including carbon monoxide, lead, and mercury. Bee pollen is used to treat allergies, since it desensitizes the individual. There have also been studies showing that bee pollen strengthens the resistance of the immune system to both cancer and radiation.
- Optimum Health – A Cardiologist’s Prescription for Optimum Health by Stephen T. Sinatra, M.D.

Bee Pollen Description: Bee pollen is the pollen produced by flowering plants, which clings to bees as they gather nectar. Bee pollen contains many vitamin and minerals, as well as flavonoids such as rutin and quercitin. It is thought that the minute amounts of pollens desensitize a person for the same pollen allergies.
- Prescription for Natural Cures: A Self-Care Guide for Treating Health Problems with Natural Remedies Including Diet and Nutrition, Nutritional Supplements, Bodywork, and More by James F. Balch, M.D. and Mark Stengler, N.D.

Some bee pollen products are tainted with contaminants from air pollution (pesticides, herbicides) and environmental chemicals (heavy metals). Therefore, I advise that you only use a product from a company that uses a quality bee pollen source and tests their product to make absolutely sure it is not contaminated.
- The Natural Physician’s Healing Therapies by Mark Stengler, N.D.

Bee pollen is another potent antiradiation food as well as a general health enhancer. Bee pollen helps to support the immune system and protects both red and white blood cells against their usual depletion from radiation. Bee pollen is also high in vitamins A, B, C, and E, nucleic acids, lecithin, cysteine, and vital minerals such as selenium, calcium, and magnesium. All of these nutrients contribute in their own way in helping to protect against radiation.
- Conscious Eating by Gabriel Cousens, M.D.

These enzymes may be a key to long life: one study showed that many centenarians in the republic of Georgia were beekeepers who regularly consumed raw honey, complete with pollen. Bee pollen is packed with amino acids (twenty-two, including all the essential ones), vitamins, minerals, hormones, fatty acids, and thousands of enzymes. Bee pollen has been found to be effective in treating allergies, bacterial infections, asthma, capillary weakness, chronic fatigue, immune depression, menopausal symptoms, nutritional disorders, prostate problems, chronic cystitis, and urinary tract infections.
- Whole Foods Companion: A Guide For Adventurous Cooks, Curious Shoppers, and lovers of natural foods by Dianne Onstad

Research dating back to 1948 found that animals whose diets were supplemented with bee pollen had a significantly lower tumor incidence. A study in Nature reported that royal jelly (derived from pollen) protected all mice injected with cancer cells for longer than 12 months, in contrast to those in the control group, injected with the same number of cancer cells, all of which died within 12 days. In studies of women suffering from inoperable uterine cancer, those given bee pollen were found to maintain strong immune systems and to suffer less from nausea, hair loss, and fatigue.
- Alternative Medicine the Definitive Guide, Second Edition by Larry Trivieri, Jr.

One of the flavonoids found in bee pollen is the powerful anti-inflammatory quercetin. And a paper in the Journal of Ethnopharmacology in 2005 found that propolis stimulates antibody production, perhaps accounting for its reputation as an immune-system enhancer. Royal Jelly: Royal jelly is a special creamy substance secreted from the nurse worker bees that stimulates the growth and development of the queen bee; without it, she’d just be a regular old worker bee.
- The 150 Healthiest Foods on Earth: The Surprising, Unbiased Truth About What You Should Eat and Why by Jonny Bowden, Ph.D., C.N.S.

Bee pollen can be wonderful for improving focus, if the child is not allergic to bee stings. It is especially high in B vitamins, which are essential for good mental health. Vitamin E with selenium aids circulation, as do choline and inositol. Moreover, vitamin C, an effective free radical scavenger, builds the immune system and improves circulation. Research suggests that the amino acid L-glutamine is helpful for anyone with mental and emotional problems.
- The Complete Encyclopedia of Natural Healing: A Comprehensive A-Z Listing of Common and Chronic Illnesses and Their Proven Natural Treatments by Gary Null, Ph.D.

http://www.naturalnews.com/027566_bee_pollen_immune_system.html

Children Need More Dirt to be Healthy

nicole — Tue, 10 Aug 2010 16:11:46 +0000

Researchers from the University of California, San Diego, have found that children who are too clean are at a higher risk of developing inflammation and disease. Normal skin bacteria that act to balance immune response protect the body from overreacting to cuts and other injuries. Excessive cleanliness is actually impairing children’s natural healing function and putting them at an increased risk for disease.

Published in the online edition of Nature Medicine, findings are confirming that germ exposure is beneficial to young children who need it in order to build immunity and prevent the onset of allergies. Being too clean is now implicated in causing increased allergies in developed countries around the world.

Staphylococci, the bacterial species studied by researchers, was found to play a vital role in blocking inflammation. It creates a molecule called lipoteichoic acid (LTA) that keeps skin keratinocytes balanced and prevents them from creating too much inflammation. As a result, a simple cut or scrape will not get overly swollen in the presence of staphylococci.

Overuse of skin soaps, body washes, and hand sanitizers is eliminating this important bacteria, leading many researchers to question hygiene methods that have become commonplace. Children are being restricted from “dirty” outdoor activities in the name of keeping them safe from germs, when in fact these restrictions are causing them more harm than good.

Several groups in the United Kingdom, including Parents Outloud and Allergy UK, believe that the research proves that children are being overprotected from germs and that exposure to elements like dirt and sand is a good thing for them. Since allergy rates have tripled in the UK over the past ten years, advocates of germ exposure hope that the findings will cause many to reevaluate their ideas concerning childhood health.

A rapid rise in allergies, asthma, autoimmune disorders, diabetes, and serious inflammation diseases are also being seen in the United States where the sanitation craze has also taken hold. Science has shown that the human body maintains health because of the presence of trillions of different microbes that keep each other in check. Antibacterial products and other sanitation products can cause the growth of super-bacteria that can cause serious problems.

Children who grow up on farms and are exposed to all sorts of bugs, worms and natural elements have demonstrably less allergies and autoimmune problems than urban children who spend most of their time indoors. Playing outside barefoot every now and again and digging in the dirt more often would do wonders for the health of today’s youngsters.

Bee pollen superfood boosts immune system function

nicole — Mon, 26 Jul 2010 20:25:53 +0000

Bee pollen and your immune system

Your adrenals, which really take a beating from stress, can be strengthened with green drinks, sea vegetables, licorice, bee pollen, royal jelly, and ginseng. Many herbs have antioxidant properties that help combat free radical damage related to an immune system weakened by stress.
- The Super Anti-Oxidants: Why They Will Change the Face of Healthcare in the 21st Century by James F. Balch, M.D.

One good source of B vitamins is bee pollen, unless there is an allergy to bee stings. Other good sources are green algae and the bioflavonoid pycnogenol. And taking pycnogenol daily (60 mg) has the side benefit of keeping the skin healthy and young. Vitamin A is healing to the skin as well, and preventive against infections. Another important nutrient is coenzyme Q10, which provides oxygen to the tissues, helping them to heal. Herbs: There is an abundance of herbs that support the immune system before or during an outbreak.
- The Complete Encyclopedia of Natural Healing: A Comprehensive A-Z Listing of Common and Chronic Illnesses and Their Proven Natural Treatments by Gary Null, Ph.D.

http://www.naturalnews.com/027566_bee_pollen_immune_system.html

New study connects fiber-rich diet and intestinal bacteria with strong immune system

nicole — Tue, 20 Jul 2010 12:31:54 +0000

You probably know that getting enough fiber in your diet can keep constipation at bay and it can lower high cholesterol levels, too. Now Australian researchers have found another reason why the indigestible part of plant-based foods, known as roughage, is good for you — it plays an important role in keeping your immune system healthy and in preventing specific diseases.

When fiber moves through the digestive tract it remains mostly unchanged, working as a type of internal broom. Then, in the colon, bacteria interact with roughage. Fermentation takes place, producing compounds called short-chain fatty acids (SCFAs) which are known to help soothe ulcerative colitis, an inflammatory gut condition. Probiotics and prebiotics, beneficial bacteria found in kefir, yogurt and nutritional supplements, affect the healthy balance of gut bacteria and have been documented to help the symptoms of two other inflammatory diseases, asthma and rheumatoid arthritis.

But what is the connection between fiber, “good” intestinal bacteria and the healing of disorders marked by inflammation? In a study just published in the science journal Nature, Sydney-based scientists say they’ve found the answer to that question. They’ve discovered a mechanism that explains how a plant-based diet rich in fiber works with beneficial gut bacteria and the immune system to promote health and potentially prevent a host of diseases.

Kendle Maslowski, a PhD student, and Professor Charles Mackay from the Garvan Institute of Medical Research, working in collaboration with the Co-operative Research Center for Asthma and Airways, have demonstrated that a molecule dubbed GPR43 expressed by immune cells and previously shown to bind SCFAs reduces inflammation. They found that mice lacking the GPR43 gene have increased, unresolved inflammation in their bodies because their immune cells can’t bind to and use SCFAs.

So how does this information translate into helping human health? “We’re now beginning to understand that from the moment you’re born, it’s incredibly important to be colonized by the right kinds of gut bacteria. The kinds of foods you eat directly determine the levels of certain bacteria in your gut,” Maslowski explained in a statement to the press. “Changing diets are changing the kinds of gut bacteria we have, as well as their by-products, particularly short-chain fatty acids. If we have low amounts of dietary fiber, then we’re going to have low levels of short chain fatty acids, which we have demonstrated are very important in the immune systems of mice.”

Professor Mackay pointed out in the press statement that the notion what you eat might have profound effects on immune responses and inflammatory diseases has never been taken seriously enough. “We believe that changes in diet, associated with western lifestyles, contribute to the increasing incidences of asthma, Type 1 diabetes and other autoimmune diseases. Now we have a new molecular mechanism that might explain how diet is affecting our immune systems,” he stated.

The scientists conclude that their current research provides compelling reasons to eat a diet rich in unprocessed whole foods such as fresh fruits, vegetables, grains, nuts and seeds. “The role of nutrition and gut intestinal bacteria in immune responses is an exciting new topic in immunology, and recent findings including our own open up new possibilities to explore causes as well as new treatments for inflammatory diseases such as asthma,” said Professor Mackay.

http://www.naturalnews.com/027551_intestinal_bacteria_immune_system.html

Rare Hybrid Cell Key to Regulating the Immune System

nicole — Tue, 15 Jun 2010 12:29:15 +0000

A cell small in number but powerful in its ability to switch the immune system on or off is a unique hybrid of two well-known immune cell types, Medical College of Georgia researchers report.

“This is actually the first cell we know of that has this type of appearance in nature,” Dr. Andrew Mellor, molecular geneticist and immunologist who co-directs MCG’s Immunotherapy Discovery Institute, said of the cell that looks like a dendritic cell and a B cell but isn’t really either.

The discovery of this rare hybrid could have implications for the efficacy of new therapies that manipulate these two cell types to treat diseases such as cancer and rheumatoid arthritis.

When MCG scientists first reported the human equivalent of this cell in Science in 2002, they called it a subset of the dendritic cell that clusters in high exposure areas such as the gut but also roams the body, looking for invaders like a virus or cancer. Dendritic cells show their find to T cells, telling them to ignore or attack by bringing trash-eating macrophages, natural killer cells and the like into the fight.

What seemed most unique about the subset is its ability to express indoleamine 2,3 dioxygenase, or IDO, to turn off T cells. IDO is an enzyme used by fetuses and tumors alike to escape the immune response.

The new studies show that is only part of the cells’ distinctiveness. The cells also have the identifying markings of B cells, known for their ability to make antibodies against invaders. In fact, they found the IDO-presenting cells came from the same precursor cell as B cells. But, when the scientists looked at mice missing B cells, they still found the IDO-producing cells. Hence, the cell didn’t need to produce antibodies to turn off T cells.

In reality, IDO-expressing cells have properties of both cells, said Burles A. Johnson III, an MCG M.D.-Ph.D. student and first author of the paper published online this week in PNAS. “It looks like a B cell and it’s not. It looks like a dendritic cell and it is and it isn’t,” Johnson said.

While their studies are in mice, the cells also are in humans, showing up in some unfortunate places such as the drainage system for tumors, melanoma or even HIV where they likely help the diseases survive.

They also may be showing up in new dendritic cell therapies designed to strengthen the immune response to cancer. If the therapies happen to include some IDO-expressing cells, those could end up helping the cancer, said Mellor, the paper’s corresponding author. ”All you need is a few of these cells in your dendritic cell vaccine and you don’t get stimulation any more, you get suppression,” Mellor said.

Their confusing face could also cause hybrids to be lost in B cell-depleting therapies designed to lessen the immune system’s attack on joints in rheumatoid arthritis. “These therapies may also deplete IDO-expressing cells and decrease therapy effectiveness because you are eliminating cells that are there to help you,” Johnson said.

“This gives us new insight into why these therapies might not be working as well as we think they might,” Mellor added. Long-term goals include figuring out how to manipulate the hybrid’s activity to benefit patients.

The research was funded by the National Institutes of Health and the Germany-based pharmaceutical company Boehringer-Ingelheim. Mellor is a Georgia Research Alliance Eminent Scholar in Molecular Immunogenetics.

http://insciences.org/article.php?article_id=9022