Category Archives: Allergy

Zur Geschichte der Klimaforschung

Es ist nicht einfach, hier einen Überblick zu bekommen.

Jedenfalls sollte man von Qualität der Wettervorhersagen (die für die nächsten 24 Stunden von 75% auf über 90% in den letzten 20 Jahren gestiegen ist), nicht auf die Qualität der Klimavorhersagen schliessen.

Die Geschichte der Klimaforschung kann jedenfalls in drei Beiträgen lückenlos nachgelesen werden:

Wenn der Wind weht

Wenn der Wind weht” mit diesem Film (und seiner Titelmelodie von David Bowie) sind wir Mitte der 80er Jahre sozialisiert worden. Der drohenden Atomkrieg, das war eine echte, reale, unmittelbare Gefahr wenn einer der Pershing II in die Luft geflogen wäre..

Roland Emmerichs Katastrophenfilm The Day after Tomorrow 2004 konnte das kaum noch toppen, wobei Experten aber der Meinung sind, dass die Spiefilme einen falschen Eindruck der Kimakrise vermittelt haben: zu sehr Katastrophen-orientiert bekommt man nur das Gefühl der Ohnmacht; neben der erfundenen Darstellungen einer allumfassenden Katastrophe kommt die reale Erderwärmung vergleichsweise harmlos daher.

Oder doch nicht, wenn man sich “chasing ice” ansieht?

Urs Bruderer hat diese Frage in einem wunderbaren Essay über “Die große Überforderung” thematisiert

Ich habe die Klimakatastrophe viele Jahre kaum beachtet. Und hielt das für die klügste Entscheidung.
Seit Menschen denken können, warnen sie vor ihrem Ende.

Ob der Atomkrieg, das Waldsterben oder das Auslaufen des Maya-Kalenders im Dezember 2012, ob im Cern produzierte schwarze Löcher, Milleniumsbug oder Vogelgrippe – im Rückblick bewies jedes Weltuntergangsszenario nur, dass wir eine Lust an der Angst vor dem Ende haben.

Der Weltklimarat hat inzwischen unzählige Berichte und Sonderberichte veröentlicht. Die Warnungen wurden immer genauer und bedrohlicher. Und ich wurde immer besser darin, sie zu überhören.

Einen Artikel, den man in Ruhe vollständig gelesen haben muss.

A 498 references paper on climate change and allergy

This is certainly the most comprehensive paper that examines the association of air pollution, climate change and allergen exposure.

Air pollution and climate change are potential drivers for the increasing burden of allergic diseases. The molecular mechanisms by which air pollutants and climate parameters may influence allergic diseases, however, are complex and elusive.

Certainly there is no causal effect of allergens on human allergy, as allergens have been always abundant even without allergy. Nevertheless allergens are drivers aggravating symptoms in allergy-prone patients by basically four factors

  1. Stability effects; influencing the accumulation and degradation of allergenic proteins, the duration of exposure times to cellular receptors, and the process of antigen presentation via major histocompatibility complex (MHC) class II
  2. Epitope effects, i.e., generation of new epitopes or modification of existing epitopes, changing the binding properties of antibodies and receptors, by direct chemical modification or as a result of conformational changes
  3. Adjuvant effects, i.e., generation of new adjuvant functions or modification of existing adjuvant functions such as lipid-binding capacities due to modified ligand binding sites
  4. Agglomeration effects, i.e., multiplication or shielding of epitopes or adjuvant functions by cross-linking (oligomerization) of allergenic proteins, which may enhance the cross-linking

I would add even 5. that the absolute number of pollens increased in some areas as a stress response of dying trees.

Harmed by the hygiene hypothesis

A new paper by a British-Kazakhstan-Armenian group nicely summarizes why we need good hypothesis papers.
As a deterring example they use the hygiene hypothesis

the hygiene hypothesis that was originally proposed by David Strachan in 1989. David Strachan studied the epidemiology of hay fever in a cohort of 17,414 British children and concluded that declining family size and improved personal hygiene had reduced the chances of cross infections in families, resulting in epidemics of atopic disease in post-industrial Britain. Over the past four decades, several related hypotheses have been proposed to expand the potential role of symbiotic microorganisms and parasites in the development of human physiological immune responses early in life and protection from allergic and autoimmune diseases later on.

I agree with the description although David never claimed to be the first author writing about the hygiene hypothesis. When I spoke to him the last time London he wasn’t even happy with this popularity.

The chain certainly started also much earlier than 1989 with “continuing activity of an immune system made redundant by man’s cleanliness” (Godfrey, 1975) continued with Gerrard 1976, Frick 1986, Busse, 1989 until David Barker argued in 1985 that there is a “decreased incidence of infection among children, especially in wealthier families, that changed their pattern of immunity”.

The harm inducted by the hygiene hypothesis is described as

The misunderstanding of the hygiene hypothesis that primarily aimed to shed light on the role of the microbiome in allergic and autoimmune diseases resulted in decline of public confidence in hygiene with dire societal implications, forcing some experts to abandon the original idea. Although that hypothesis is unrelated to the issue of vaccinations, the public misunderstanding has resulted in decline of vaccinations at a time of upsurge of old and new infections.

I fear the authors are right – some people may have been harmed by the hygiene hypothesis leading them back in the pre-Semmelweis era.

Useful reveal.js plugins

The list is somewhat hidden but here is the link https://github.com/hakimel/reveal.js/wiki/Plugins,-Tools-and-Hardware
My preference is

dependencies: [
{ src: 'library/reveal.js/lib/js/classList.js', condition: function() { return !document.body.classList; } },
{ src: 'library/reveal.js/plugin/highlight/highlight.js', async: true, callback: function() { hljs.initHighlightingOnLoad(); } },
{ src: 'library/reveal.js/plugin/zoom-js/zoom.js', async: true },
{ src: "library/speech.js",
callback: function() {
RevealSpeech.configure({
nextKeyword: 'nextslide', 
prevKeyword: 'previousslide',
lastKeyword: 'lastslide',
firstKeyword: 'firstslide',
debug: true,
lang: 'en-GB' // default de-DE
});
}

plus zenpen in an iframe.

The slide builders at the plugin page are quite useless except for slides.com which is, however, too expensive.
I therefore design everything in Keynote, export as jpg and loop over all jpgs to write the section tags.

The best option would certainly be if Apple would directly support reveal.js and not some fancy own HTML formats

slide/assets/7D643FA7-9A1F-45A5-A30F-7828735F3C35/7D643FA7-9A1F-45A5-A30F-7828735F3C35.json

Or is anyone willing to write a converter?

A new research route for fighting allergy?

Sci Immunol today shows an incomplete genetic reconstitution of B cell pools after measles infection.

Using B cell receptor (BCR) sequencing of human peripheral blood lymphocytes before and after MeV infection, we identified two immunological con- sequences from measles underlying immunosuppression: (i) incomplete reconstitution of the naïve B cell pool leading to immunological immaturity and (ii) compromised immune memory to previously encountered pathogens due to depletion of previously expanded B memory clones.

This “immune amnesia” is noteworthy as sensitivity to D pter was observed less frequent in children with a history of measles than in those without.

City-Country-River

It was the first big study as a Postdoc, that I did in 1989, comparing the City of Munich and Upper Bavaria but we did not findmany differences.  Suddenly, however, there is an increased interest in city – urban differences. Two papers appeared yesterday, one in ScienceVulnerability of the industrialized microbiota” and in Environment InternationalUrban-associated diseases: Candidate diseases, environmental risk factors, and a path forward“. Continue reading City-Country-River

VDR variants are associated with asthma

It is always nice to see an own study 15 years later appearing in a meta-analysis. A new paper in the Annals of Allergy, Asthma and Immunology now shows the results of 17 case–control studies.

Pooled odds ratio (OR) and 95% confidence interval of individual studies and pooled data for the association between TaqI polymorphism and asthma risk in overall populations and B for tt vs. TTof the TaqI variant.

We are in line #1…

Primary prevention of cow’s milk sensitization and food allergy by avoiding supplementation

A new study by Urashima et al. shows that sensitization to cow’s milk and food allergy, including CMA and anaphylaxis, are primarily preventable by avoiding CMF supplementation for at least the first 3 days of life. Although examined only indirectly, vitamin D supplements could be involved in the sensitization process.

Note to self – this is study no 4 of vitamin D related RCTs
1. De Montis G, Gendrel D, Chemillier-Truong M, Dupont C. Sensitisation to peanut and vitamin D oily preparations. The Lancet 1993;341(8857):1411.6.
2. Norizoe C, Akiyama N, Segawa T, Tachimoto H, Mezawa H, Ida H, Urashima M. Increased food allergy with vitamin D: A randomized, double-blind, placebo-controlled trial. Pediatr Int 2014; 56:6-12.7.
3. Rueter K, Jones AP, Siafarikas A, Lim EM, Bear N, Noakes PS, et al. Direct infant UV light exposure is associated with eczema and immune development. J Allergy Clin Immunol 2018; in press, doi: 10.1016/j.jaci.2018.08.037.

BTW The Urashima study is accompanied by a valuable editorial of George du Toit and Kari Nadeau

There is currently a lack of consensus among national allergy societies .. Although the EAACI3 and American Academy of Allergy, Asthma and Immunology (AAAI) currently recommend the use of hypoallergenic formulas in infants at high risk of allergy, the Australian Society of Clinical Immunology and Allergy does not. The EAACI and the AAAI are likely to reconsider their guidelines because results of more re- cent studies have been contradictory. …
Guidelines in the United States and United Kingdom recommend routine vitamin D supplementation in all breastfed infants, whereas guidelines in Australia recommend supplementation only in breastfed infants at high risk of vitamin D insufficiency.

I think I will emigrate to Australia.

 

Medizin ist keine Wissenschaft sondern eine Kunst

Fragil ist das wissenschaftliche Fundament in der Medizin ja schon immer auch wenn es die hauptsächliche Abgrenzung zur Quacksalberei ist.
Aber auch wenn man sich manche Fragen der Schulmedizin genauer anschaut, wie zum Beispiel letzte Woche die Empfehlung zu Säuglingsnahrungen oder heute ein Artikel zu Verschreibungen auf Säuglingsstationen, dann ist das weder Wissenschaft noch Kunst sondern bestenfalls industriegeleiteter Aktionismus.
Mesek et al. untersuchten dabei in 21  europäischen Ländern die Verschreibungspraxis auf 89 Stationen. Versorgungsforschung ist ja noch am nähesten an der Realität.

Vitamine sind die am häufigsten verschriebene Pharmaka, wobei unklar ist, warum in machen Regionen 74% und in andern nur 5% Vitamine verschreiben. Wenn es generall notwendig wäre, warum dann nicht 100%? Und wenn es nicht notwendig ist, warum dann nicht 0%?

An open letter to EAACI / PAAM 2019 organizers

Together with many other colleagues I was astonished about the Nestle booth at EAACI / PAAM 2019 conference in Florence.

The advertisement of Nestle for the NAN HA formula (“state-of-the-art routine infant formula“, „proven to reduce the risk of atopic dermatitis“, „long term effects up to 15 years of age“) along with other milk marketing violates recommendations of the WHO and other medical organisations about breast-feeding. None of the claims made is justified from a scientific viewpoint.

Having paid 650 € entry fee for a 3 day conference, it is also not acceptable that Dr Antonella Muraro (Padua) explains in Symposium 9 “Special products for cow’s milk allergy“ that if Nestle would not be sponsoring the event, the congress fees would be even higher.

At present, there is no generally accepted benefit of any baby food on long-term allergy prevention while also the therapeutic benefit is questionable. Commercial baby food may even increase later allergy by including supplements that are itself allergenic.

We therefore recommend a review of the EAACI ethics guidelines of industry sponsorship, and an immediate action against further participation of Nestle at future EAACI allergy congresses.

Schutz vor Allergie auf dem Bauernhof: Ist das zentrale Paradigma falsch?

Keine Frage, die Lebensbedingungen auf Bauernhöfen sind anders. Mehr Tiere, mehr Dreck, mehr frische Luft, alles ist anders als in einer Großstadt. Das kann auf Selektionsbedingungen zurückzuführen sein, und ist gut  zu sehen bereits in einer der ersten Studien vor 30 Jahren.

Clin Exp Allergy. 1999 Jan;29(1):28-34. https://doi.org/10.1016/S0140-6736(01)06252-3

Auch die Eltern hatten schon weniger Allergien, und damit logischerweise auch die Kinder.

Wenn man genau hinschaut, dann haben alle Bauernhofstudien allerdings immer wieder dieselbe Argumentationsstruktur: weil die Bedingung X dort so ist, dann kann die Folge Y iauch auf die Bedingung X zurückgeführt werden. Allerdings machen immer mehr Beschreibungen von X die Story nicht glaubwürdiger.  Keine der jemals beschriebenen Bedingungen X, ist aus dem Bauernhofmilieu heraus auf eine allgemeine Situation übertragbar gewesen, von einem einzigen verunglückten Versuch einmal abgesehen. Natürlich hat ein hoher Endotoxin Spiegel auf den Bauernhöfen eine bestimmte Wirkung –  zumindest bei einigen Menschen und bei einigen Mäusen – aber ist das wirklich  mehr als ein modifizierender Faktor?

Da Lebensbedingungen auf dem Bauernhof angeblich protektiv sind, müsste eigentlich auch mal ein Kinder präsentiert werden, die eigentlich eine Allergie haben müssten.  Aber solche Kind gab es bisher nicht, weil auch schon die Eltern keine Allergien hatten.

Farming and allergy prevention could be caused by Berkson’s fallacy

Lets look at the Wikipedia definition first

Berkson’s fallacy is a result in conditional probability and statistics which is often found to be counterintuitive, and hence a veridical paradox. It is a complicating factor arising in statistical tests of proportions. Specifically, it arises when there is an ascertainment bias inherent in a study design … The most common example of Berkson’s paradox is a false observation of a negative correlation between two positive traits, i.e., that members of a population which have some positive trait tend to lack a second.

The original example is developed using the example of an hospital based group of patients. The only thing to know is that diabetes is a risk for cholecystitis in the general population.

Any given hospital in-patient without diabetes must have another disease (otherwise he would not be there), for example cholecystitis. And by definition this will be cholecystitis without diabetes caused by some other risk facors (female, fat, forty…) So in this group of in-patients there maybe a spurious negative association between cholecystitis and diabetes.

My example here is with families who are living on farms. Since around 1960  [Leynaert 2001] there is this interesting observation that farming families have less allergy, an effect that I found back in 1989 and that is most likely a healthy farmer effect.
This selected farm population has a lower allergy prevalence and of course their children will also have less allergy. All the negative correlations (that are interpreted as protection) with endotoxin, microbiome, etc could be caused by Berkson’s fallacy (Linneberg 2005). The observation will also be even replicated as the same selection criteria are also present in the replication sample.

It seems that I am not the first to

Many more cognitive biases could also be involved: anchoring, availability cascade, confirmation and expectation bias and of course: law of the instrument.

What is wrong with the 2011 NEJM paper?

N Engl J Med 2011;364:701-9 is another paper with 1000+ citations  that had a lasting impression on some but not all people.

First, I can’t remember of any study with such an enormous selection bias  where >94% of individuals have been lost.

Second, we should not forget that farm is not protective per se – farmers may just avoid a known allergy risk factor.  PARSIFAL participants in this study included Steiner schools — anthroposophic medicine mostly avoids vitamin D (ref). This is of course a major issue for any cross-sectional study that doesn’t take into account the temporality of events.

Third, in PARSIFAL dust from children’s mattresses were collected by vacuuming — it is not very likely that many helminthic eggs were transported  from stable to bedroom. In GABRIELA, only airborne dust samples  were collected which again may miss helminth eggs although being certainly present in stable dust.

Fourth, more  microbial exposure and more fungal taxa on farms are a trivial finding.

The inverse associations of the diversity scores with asthma were not confounded by status with respect to living on a farm because adjustment did not change the respective point estimates for asthma (Table 2), although the associations became nonsignificant.

Small sample size, borderline p-values even after a long fishing expedition?

What do these strange “probability” plots  really show – the probability of asthma or the probability to live on a farm?

N Engl J Med 2011;364:701-9 Figure 3 Does it refute any general effect of diversity?

The plots are misleading if adjustment for farm living does not change the parameter estimates for bacterial/fungal diversity.

Sixth – even many years later, the main findings of this study have not been independently replicated. There is not any single study that shows listeriosis (Listeria) or diphtheria (Corynebacterium)  to be protective.