Immunology
Nigeria to launch mass polio immunization drive
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Nigeria will launch a new campaign to vaccinate millions of children against polio Wednesday in an attempt to curb the spread of the disease that has crippled hundreds this year, the World Health Organization said.
Africa’s most populous country, which accounts for more than 50 percent of new polio cases in the world, has struggled to tame the contagious disease since some states in the mainly Muslim north imposed a year-long vaccine ban in mid-2003.
New polio infections in Nigeria have climbed 225 percent to 751 this year from the same period last year because many children in the north missed several rounds of immunization toward the end of 2007, health officials said.
Research Findings in Allergen Immunotherapy Unveiled
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Researchers are presenting more than 450 abstracts on investigational findings in the diagnosis and treatment of allergic diseases at the ACAAI Annual Meeting in Seattle, Nov. 6-11. Following are highlights of some key studies on allergen immunotherapy.
“Subcutaneous Immunotherapy Reduces Future Sensitization in Allergic Children under Six Years of Age.” (Abstract #18: Nov. 9 at 1:15 p.m.) – Zachary D. Jacobs, M.D., Columbia, Mo., et al – Although controversy exists over the use of allergen-specific subcutaneous immunotherapy (SCIT) among children under six, studies show it is safe and effective in this group and may prevent the development of asthma in sensitized patients. In this retrospective chart review of one Midwest allergy clinic from 1992-1997, investigators identified 59 patients on SCIT aged 18 months to 5 years for analysis. In patients receiving SCIT, sensitivities decreased 10 percent. In contrast, the control group had a highly significant increase of 62 percent in sensitivities. Authors recommend SCIT should be considered in pediatric patients with allergic rhinitis as young as 18 months to reduce future sensitizations.
“CYT003-QbG10, A Novel Allergen-independent Immunotherapy, Shown to be Safe and Efficacious in Placebo-controlled Phase II Study.” (Abstract #19: Nov. 9 at 1:30 p.m.) – Audra Blaziene, M.D., Ph.D., Vilnius, Lithuania, et al – New disease-modifying drug candidate QbG10 significantly reduces allergy symptoms in Phase II clinical trial. Current immunotherapy is based on the repeated application of allergen components, and, with up to 80 injections, it is inconvenient and may cause frequent adverse events due to allergen exposure. Here, the investigators present a completely novel allergen-independent immunotherapy that does not contain any allergen components. QbG10 consists of short stretches of synthetic DNA that are packaged into virus-like particles. In a placebo-controlled phase II study with 80 patients, six weekly injections of QbG10 have been shown to be safe, very well tolerated and efficacious in lowering allergy symptoms in daily life compared to placebo (reduction of total symptom score by -61% for QbG10 versus -32% for placebo, p=0.008). The authors conclude that this new drug candidate has potential as a convenient, well tolerated and disease-modifying therapy able to address a broad range of allergies.
Efficacy, Dosage Concerns Unresolved on Sublingual Immunotherapy
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Although sublingual immunotherapy (SLIT) is used in Europe and other countries, experts at the annual meeting of the American College of Allergy, Asthma and Immunology (ACAAI) in Seattle say questions remain unanswered regarding its effectiveness, appropriate use, dosage, and safety of administration.
“Sublingual immunotherapy has gained wide acceptance in the treatment of allergic disease throughout Europe and South America, but the research studies in the United States have yet to show results that will convince the FDA to approve a product,” said Ira Finegold, M.D., clinical professor of medicine at Columbia University and chairman of the R.A. Cook Institute of Allergy, St. Luke’s-Roosevelt Hospital, New York.
“The main advantage of SLIT over traditional immunotherapy is patient convenience, since it is not an injection but oral drops or tablets that can be administered at home, and it appears to be safer than conventional immunotherapy,” he said.
Neurotransmitter defect may trigger autoimmune disease
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A potentially blinding neurological disorder, often confused with multiple sclerosis (MS), has now become a little less mysterious. A new study by researchers at the Mayo Clinic in Rochester, Minnesota, may have uncovered the cause of Devic’s disease. Their new study, which will appear online on October 6th in the Journal of Experimental Medicine, could result in new treatment options for this devastating disease.
Devic’s disease, also known as neuromyelitis optica (NMO), results in MS-like demyelinating lesions along the optic nerves and spine. Affected individuals often experience rapid visual loss, paralysis, and loss of leg, bladder, and bowel sensation. Some lose their sight permanently. Unlike MS, Devic’s disease can be diagnosed by the presence of a specific self-attacking immune protein—an autoantibody referred to as NMO-IgG—in the blood. Until now, however, clinicians didn’t know how that protein damaged nerves and contributed to disease symptoms.
Monitoring immune responses in disease
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A recent study (doi:10.1016/j.clim.2008.06.009) published in Clinical Immunology, the official journal of the Clinical Immunology Society (CIS), describes a new method enabling the detection of multiple parameters of single human cells. The report demonstrates the characterization of specific blood cells from an individual with type 1 diabetes, providing information about the role these cells might play in the development of the disease and during therapy.
Classification of blood cells, including B and T cells, is important for distinguishing immune responses to pathogens, allergens, or self-antigens in autoimmune diseases. Although various techniques are available to identify cell surface determinants, cytokines and antibodies secreted by blood cells, so far it has not been possible to study multiple secreted proteins while also assigning surface displayed markers to individual living cells.
A collaborative group of investigators from Harvard Medical School and Massachusetts Institute of Technology in the USA, describe how a combination of existing and enhanced immunological methods can identify and characterize rare B cells from blood of a recent onset type 1 diabetic subject.
New role for Natural Killers!
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Scientists at the University of York have discovered a new role for a population of white blood cells, which may lead to improved treatments for chronic infections and cancer.
Natural Killer (or NK) cells are abundant white blood cells that were recognised over 30 years ago as being able to kill cancer cells in the test tube. Since that time, a role for NK cells in activating other white blood cells (including ‘T’ lymphocytes and phagocytes) and in directing how the immune system responds to a wide range of infections has also been established.
Because of these properties, NK have been widely regarded as being of benefit in the fight against cancer and infection, and methods to increase NK cell activity underpin a range of new experimental anti-cancer drugs and anti-infectives.
Joint replacement may improve osteoarthritis symptoms in older adults
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Older adults who have hip or knee replacement surgery for severe osteoarthritis may take several weeks to recover but appear to have excellent long-term outcomes, according to a report in the July 14 issue of Archives of Internal Medicine, one of the JAMA/Archives journals.
As the U.S. population ages, the number of older adults with osteoarthritis is increasing, according to background information in the article. The disease causes debilitating pain and often restricts older adults’ mobility. Non-invasive treatments such as medications and physical therapy appear to be of limited value for the advanced stages of osteoarthritis. However, surgery may be associated with risks and discomfort.
Mary Beth Hamel, M.D., M.P.H., and colleagues at Beth Israel Deaconess Medical Center, Boston, studied medical decision-making and treatment outcomes in 174 patients age 65 and older (average age 75.2) who had severe osteoarthritis of the hip or knee. Participants’ arthritis symptoms and functional status were assessed at the beginning of the study, between 2001 and 2004, and again 12 months later. Patients who chose to have joint replacement surgery were assessed six weeks, six months and 12 months after the procedure.
Special infant formulas cut long-term allergy risk
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Hypoallergenic infant formulas may help lower the long-term risk of allergies in children who are genetically vulnerable to them, a new study suggests.
The products, known as hydrolyzed infant formulas, are designed to lower the likelihood of the allergic responses some infants have to standard formula.
Like standard formula, hydrolyzed products contain cow’s milk proteins; the difference is that the proteins are broken down so that they are less allergenic than the whole proteins in regular formula.
Major shift in HIV prevention priorities needed
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According to a new policy analysis led by researchers at the Harvard School of Public Health (HSPH) and the University of California, Berkeley, the most common HIV prevention strategies—condom promotion, HIV testing, treatment of other sexually transmitted infections (STIs), vaccine and microbicide research, and abstinence—are having a limited impact on the predominantly heterosexual epidemics found in Africa. Furthermore, some of the assumptions underlying such strategies—such as poverty or war being major causes of AIDS in Africa—are unsupported by rigorous scientific evidence. The researchers argue that two interventions currently getting less attention and resources—male circumcision and reducing multiple sexual partnerships—would have a greater impact on the AIDS pandemic and should become the cornerstone of HIV prevention efforts in the high-HIV-prevalence parts of Africa.
The paper appears in the May 9, 2008 issue of the journal Science.
“Despite relatively large investments in AIDS prevention efforts for some years now, including sizeable spending in some of the most heavily affected countries (such as South Africa and Botswana), it’s clear that we need to do a better job of reducing the rate of new HIV infections. We need a fairly dramatic shift in priorities, not just a minor tweaking,” said Daniel Halperin, lecturer on international health in the HSPH Department of Population and International Health and one of the paper’s lead authors.
Study shows promising new approach to thwart HIV
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Researchers have pinpointed a protein contain within key human immune system cells that is needed for the AIDS virus to infect the cells, and found that turning it off can greatly slow down the deadly virus.
Inactivating a protein called ITK in immune system cells called T cells reduces HIV’s ability to enter these cells and replicate itself, the researchers said on Monday.
A drug based on this approach could be useful as a complement to existing drugs used to treat HIV infection, said Andrew Henderson of Boston University, one of the researchers.
Daily asthma meds keep lungs in play during exercise
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Taking asthma medication daily can help prevent the tightening of the airways or “bronchoconstriction” with physical exertion that affects many children with asthma, a new study from Poland confirms.
Dr. Iwona Stelmach of N. Copernicus Hospital in Lodz and colleagues found that of the four treatments they evaluated, the two including the anti-asthma drug montelukast (Singulair) were the most effective, but all were better than placebo.
“Control of childhood asthma with exercise-induced bronchoconstriction can be obtained by using regular controller treatment,” Stelmach and colleagues write in the Journal of Allergy and Clinical Immunology.
The HLA-DRB1 gene and premature death in rheumatoid arthritis
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People with rheumatoid arthritis (RA), an inflammatory autoimmune disease, tend to die younger and, largely from cardiovascular disease (CVD). One explanation for this increasingly recognized fact is that inflammation promotes atherosclerosis. A marker of inflammation, elevation of the C-reactive protein (CRP) level has been shown to predict CVD in the general population. However, other highly inflammatory diseases—Crohn’s, for example—do not carry the same high risk of premature death from heart disease.
To identify other possible suspects, researchers in the United Kingdom investigated whether genetic variants linked to the likelihood of developing RA might also make patients more likely to die from CVD. Led by Dr. Tracey M. Farragher at the University of Manchester and funded by the Arthritis Research Campaign (arc), the study focused on two genes—HLA-DRB1and PTPN22—and their interactions with known RA risk factors. The evidence, presented in the February 2008 issue of Arthritis & Rheumatism, implicates HLA-DRB1 genotypes, already associated with RA susceptibility and severity, as a predictor of premature death from CVD for inflammatory arthritis patients. For RA patients in particular, having the shared epitope (SE)—a group of HLA-DRB1 alleles with kindred amino acid traits—plus anti-cyclic citrullinated peptide (anti-CCP) antibodies and current smoking is an especially deadly combination.
Deficient regulators in the immune system responsible for type 1 diabetes
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The main regulators of the immune system, called CD4+Treg cells, are thought to be highly involved in a large range of immune diseases. The gradual reduction in their regulating capacity seems to play a critical role in the onset of type 1 diabetes, as demonstrated in the latest study by Dr. Ciriaco Piccirillo, a researcher in the Department of Microbiology and Immunology at the Research Institute of the McGill University Health Centre and the principal investigator for this project. This study was published this month in the journal Diabetes.
The immune system needs to be regulated so that it attacks only the site of an inflammation and focuses its attack on pathogens rather than on the body tissues, causing an autoimmune disease.
In a healthy patient, CD4+Treg cells deactivate any T lymphocytes, a type of immune cell, that are misprogrammed and could attack the body. Dr Piccirillo’s research indicates that in type 1 diabetic patients this control mechanism may be deficient, thereby allowing the misprogrammed T lymphocytes to proliferate and gain the ability to destroy the insulin-producing cells of the pancreas. This leads to type 1 diabetes.
Two Genes Are Important Key to Regulating Immune Response
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A research team at Weill Cornell Medical College in New York City has identified two genes that may be crucial to the production of an immune system cytokine called interleukin-10 (IL-10).
The discovery fills in an important “missing link” in a biochemical pathway that’s long been tied to disorders ranging from lupus and Type 1 diabetes, to cancer and AIDS.
Many kids may not outgrow cow’s milk allergy
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Cow’s milk allergy persists longer than previously reported, and the majority of children may retain the sensitivity into school age, study findings suggest.
“The old data saying that most milk allergy will be easily outgrown, usually by the age of 3 years, is most likely wrong,” Dr. Robert A. Wood, at Johns Hopkins University School of Medicine, told Reuters Health.
