Possible role of vitamin D in the pathogenesis of anaphylaxis

Epinephrine autoinjector (EpiPen) prescriptions (2006-2007) and anaphylaxis hospital admission rates (2002-2007) were used as surrogate markers of anaphylaxis.

EpiPen prescription rates (per 100,000 population per year) were higher in children from birth to the age of 4 years than in the overall population. Decreasing latitude was associated with a decrease in EpiPen prescription rates - the rates were higher in southern compared with northern regions of Australia. There is more sun exposure in the northern regions (opposite of the U.S.).

Anaphylaxis admission rates showed a similar south-north gradient, such that admission rates were higher in southern compared with northern regions of Australia.

EpiPen prescription rates and anaphylaxis admissions are more common in southern regions of Australia. These data may support a possible role of vitamin D in the pathogenesis of anaphylaxis.

References:
Regional variation in epinephrine autoinjector prescriptions in Australia: more evidence for the vitamin D-anaphylaxis hypothesis. Mullins, Raymond J.; Clark, Sunday; Camargo, Carlos A. Annals of Allergy, Asthma and Immunology, Volume 103, Number 6, December 2009 , pp. 488-495(8).
Image source: Wikipedia, public domain.

Differences in allergen immunotherapy practices between the United States and Europe

In regards to allergen specific immunotherapy (SIT), there are significant differences between Europe and the United States in:

- allergen extract regulation
- standardization
- formulation
- types of allergen extracts
- routes of administration
- reimbursement

Most SIT is formulated in US allergists' offices, whereas virtually all SIT is formulated by extract manufacturers in Europe.

Sublingual immunotherapy (SLIT) represents 45% of SIT treatment in Europe but only a small percentage of US allergists (approximately 5.9%) prescribe SLIT.

References:
Comparison of allergen immunotherapy practice patterns in the United States and Europe. Cox, Linda; Jacobsen, Lars. Annals of Allergy, Asthma and Immunology, Volume 103, Number 6, December 2009 , pp. 451-460(10).
Image source: OpenClipArt.org, public domain.

Pea Allergy

Vicilin and convicilin are potential major allergens from pea seeds.

The frequency of pea allergy varies among different populations. Legume allergy, mainly to lentils and chickpeas, is the fifth most common cause of food allergy in Spanish children.

Cross-reactivity between peanut allergy and pea allergy is relatively common. Please review the text below for a detailed description.

Legumes and lentils

Peanuts and soybeans are the major legumes involved in human food allergy. Fewer data exist on adverse reactions to other temperate legumes, such as lentils.

Lentils, chickpeas, beans, and peas are the most common consumed legumes in the Mediterranean area.

Allergic reactions to lentils started early in life, usually below 4 years of age; oropharyngeal symptoms and acute urticaria were the most common symptoms through ingestion, and symptomatic reactivity to chick peas is frequently associated.

Sensitization to lupine is common peanut-sensitized adults

The use of lupine in food has been increasing during the last decade and allergic reactions to lupine have been reported, especially in peanut-allergic patients.

39 peanut-sensitized patients were evaluated by skin prick tests (SPT) and ImmunoCAP to lupine, pea, and soy (Peeters KA et al, Allergy. 2009). Clinical reactivity was measured by double-blind placebo-controlled food challenges (DBPCFC) for lupine, and by history for pea and soy. None of the patients was aware of the use of lupine in food.

82% of patients were sensitized to lupine, 55% to pea, and 87% to soy. Clinically relevant sensitization to lupine, pea, or soy occurred in 35%, 29%, and 33% respectively.

The lowest eliciting dose (ED) for lupine, inducing mild subjective symptoms, was 0.5 mg.

In this study (Peeters KA et al, Allergy. 2009), peanut-sensitized patients, clinically relevant sensitization to either lupine or to pea or soy occurs frequently. The ED for lupine is low (0.5 mg), which is only fivefold higher than for peanut.

Cross-reactivity between legumes is common

Serological cross-reactivity among legumes is frequent, but its clinical relevance is controversial. In Spanish study (Martínez San Ireneo M et al, Int Arch Allergy Immunol. 2008), the cross-reactivity among lentils, chickpeas, peas, white beans and peanuts and its clinical relevance was investigated in 54 pediatric patients. All children had a clinical allergy to legumes. Cross-reactivity was evaluated by ELISA inhibition experiments and oral food challenges to legumes.

ELISA inhibition demonstrated more than 80% inhibition with lentil, chickpea and pea extracts. The oral legume challenges demonstrated that 69% of children were allergic to 2 or more legumes (median 3 legumes).

The most frequent associations were allergy to lentils and chickpeas (57%), allergy to lentils and peas (54%) and allergy to lentils, chickpeas and peas (43%).

In vitro inhibition demonstrated a high degree of cross-reactivity among lentils, chickpeas and peas. Food challenges confirmed that clinical allergy to all three legumes is frequent.

References

Clinical features of legume allergy in children from a Mediterranean area. Martínez San Ireneo M, Ibáñez MD, Sánchez JJ, Carnés J, Fernández-Caldas E. Ann Allergy Asthma Immunol. 2008 Aug;101(2):179-84.

In vitro and in vivo cross-reactivity studies of legume allergy in a Mediterranean population. Martínez San Ireneo M, Ibáñez MD, Fernández-Caldas E, Carnés J. Int Arch Allergy Immunol. 2008;147(3):222-30. Epub 2008 Jul 2.
http://www.ncbi.nlm.nih.gov/pubmed/18594152

Vicilin and convicilin are potential major allergens from pea. R. Sanchez-Monge et al. Clinical & Experimental Allergy, Volume 34 Issue 11, Pages 1747 - 1753, 2004.
http://www3.interscience.wiley.com/journal/118792246/abstract

Allergy to lentils in Mediterranean pediatric patients. Pascual CY et al. J Allergy Clin Immunol. 1999 Jan;103(1 Pt 1):154-8.
http://www.ncbi.nlm.nih.gov/pubmed/9893199

Clinical relevance of sensitization to lupine in peanut-sensitized adults. Peeters KA, Koppelman SJ, Penninks AH, Lebens A, Bruijnzeel-Koomen CA, Hefle SL, Taylor SL, van Hoffen E, Knulst AC. Allergy. 2009 Apr;64(4):549-55. Epub 2008 Dec 4.
http://www.ncbi.nlm.nih.gov/pubmed/19076544

Image source: Frozen green peas. Wikipedia, Jina Lee, GNU Free Documentation License.

Video Shows an Unusual Cause of Epistaxis: A Leech

From the NEJM:



A 44-year-old man presented with a 7-day history of epistaxis on the left side. He reported that he had washed his face in a freshwater stream 7 days before the onset of symptoms.


A suspected blood clot was seen in the left middle turbinate on anterior rhinoscopy, although endoscopic examination showed that the possible clot was a living leech. The leech was retrieved with an aspirator. The epistaxis subsequently resolved.

Acupuncture may reduce itching in atopic dermatitis (eczema)

Pruritus (itch) is a major symptom of allergic skin diseases. Acupuncture has been shown to reduce histamine-induced itch in healthy volunteers.

The study authors investigated the effect of acupuncture on type I hypersensitivity itch and skin reaction in a double-blind, randomized, placebo-controlled, crossover trial.

An allergen stimulus (house dust mite or grass pollen skin prick) was applied to 30 patients with atopic eczema before and after:

- acupuncture at points Quchi and Xuehai, verum acupuncture (VA)
- 'placebo-point' acupuncture (PA)
- no acupuncture (NA)

Itch intensity was recorded on a visual analogue scale and with a questionnaire. After 10 min, wheal and flare size and skin perfusion (via LASER-Doppler) were measured.

Itch intensity was lower in VA compared to NA and PA. In the preventive approach, wheal and flare size were smaller in VA.

The authors concluded that acupuncture reduced type I hypersensitivity itch in patients with atopic eczema.

References:
Influence of acupuncture on type I hypersensitivity itch and the wheal and flare response in adults with atopic eczema. F. Pfab et al. Allergy, 11 Dec 2009.
http://www3.interscience.wiley.com/journal/123210618/abstract
Image source: Needles being inserted into a patient's skin, Wikipedia, public domain.

Cause of Eosinophilia: Colonoscopy Video Demonstrating a Moving Worm

From the NEJM:



A 60-year-old woman presented with abdominal discomfort that had developed over the previous several weeks. Laboratory evaluation was notable for the white-cell count, which included 1.8% eosinophils. Colonoscopy demonstrated a worm, which moved. The worm was 20 cm in length and was removed with an endoscopic snare and identified as Ascaris lumbricoides. The patient was given mebendazole. The abdominal discomfort resolved after the worm was removed.

Bacterial lipopolysaccharide (LPS, endotoxin) and CD14 play a role in development of atopy

Atopy is highly prevalent and remains the biggest risk factor for asthma. Atopy has a heritable component but is not due to genetic factors alone.

Lipopolysaccharide (LPS) and its bioactive moiety endotoxin are common to all gram-negative bacteria, and have been used as a surrogate of microbial load. Endotoxin is found in dust collected from homes. The structure of a lipopolysaccharide(LPS) is shown on the right (image source: Wikipedia, public domain).

Our innate immune system recognizes LPS via the LPS signal transduction pathway, which has the trimolecular complex of CD14/TLR4/MD2 at the core.

Generally, there is an inverse dose-response relationship between exposure to endotoxin and the risk of atopy.

High exposure to endotoxin in the domestic environment is protective against the development of atopy, but only among carriers of certain alleles.


Pathogen Recognition Receptors, TLRs. This video is from: Janeway's Immunobiology, 7th Edition Murphy, Travers, & Walport. Source: Garland Science.

References:
The role of lipopolysaccharide in the development of atopy in humans. Simpson A, Martinez FD. Clin Exp Allergy. 2009 Nov 25. [Epub ahead of print]
Toll-like receptors (TLRs)

Allergy and Immunology News of the Day



Health News of the Day is a daily summary made from the selected links I post on Twitter. It is in a bullet points format with links to the original sources which include 350 RSS feeds that produce about 2,500 items per day.

Role of sphingosine kinase 1(S1P) in allergen-induced pulmonary vascular remodeling and hyperresponsiveness http://bit.ly/1GjMsr

Asthma phenotypes dictate therapy: Only half of asthmatics have increased levels of IL-13–inducible genes http://bit.ly/2cZphR

Swimming pool chlorine increases atopy risk: swimming more than 1000 hr increases risk of allergic rhinitis & asthma http://bit.ly/2VAUwi

Dangerous Anaphylaxis Waiting Game: 40% of people suffering an episode of anaphylaxis wait before seeking med attention http://bit.ly/1HxXan

Hematopoietic stem cell transplantation in SCID results in long-term survival even w/o pretransplantation conditioning http://bit.ly/109xXf

Peripheral blood eosinophil counts could serve as a marker of inflammation to guide asthma therapy http://bit.ly/3T40Yk

Possible association between antibiotic use in first year of life and asthma, AR , and eczema in children 6-7 years old http://bit.ly/4mSZCj

Broad Spectrum Chemokine Inhibitor FX125L Is "Safe and Well Tolerated" in First Human Trial http://bit.ly/1a9qLx

Gelatin is the Culprit in Some Vaccine Reactions http://bit.ly/42A8rx

"The sinus doctor said I have inflamed tornadoes in my nose." - Dr. Grumpy: "You mean inflamed turbinates?" http://bit.ly/4EKtng

Medical news tweets are not research articles - they are 140-character messages - please always go to the original source, links, etc. Tweets and links do not represent endorsement, approval or support. Image source: OpenClipArt.org, public domain.

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Video: Acetaminophen may be linked to asthma

From Cleveland Clinic:



"It is one of the most widely-used pain relievers around. But a new study finds acetaminophen may be associated with an increased risk of asthma or wheezing in both adults and children."

This research is preliminary and no evidence-based conclusions can be drawn from it regarding therapeutic changes or recommendations.

Allergy and Immunology News of the Day

Health News of the Day is a daily summary made from the selected links I post on Twitter. It is in a bullet points format with links to the original sources which include 350 RSS feeds that produce about 2,500 items per day.

Successful treatment of vocal cord dysfunction (VCD) with low-dose amitriptyline http://bit.ly/6JKaPF

Egg white specific IgE levels - good diagnostic test that could eliminate the need to perform oral challenges in many patients? http://bit.ly/5iOUDJ -- Many allergists will disagree with this statement by the study authors.

IL-10 and IFN-γ production could be defective in allergic children prone to develop polysensitization http://bit.ly/4RyKLV

Phadia Immunocap Blog reviews SLIT http://bit.ly/6wU939 - 6% of U.S. allergists used SLIT in 2006. Dr. Mitchell is a respected proponent of SLIT (http://bit.ly/800b0G) but his blogging skills may need some improvement http://bit.ly/7PsRsk

Food Allergy & Anaphylaxis Network (FAAN) Launches a Redesigned Website http://bit.ly/Q3t2a

Yellow Fever Vaccine Induces a Broad and Polyfunctional Memory CD8+ T Cell Response http://bit.ly/8KzBGX

Alternative medicine: "Asthmatics under anthroposophic treatment had long-term improvements of symptoms and quality of life" http://bit.ly/6pxTiQ

Medical news tweets are not research articles - they are 140-character messages - please always go to the original source, links, etc. Tweets and links do not represent endorsement, approval or support. Image source: OpenClipArt.org, public domain.

Follow me on Twitter:

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