Celiac.com 08/06/2009 - A study by a team of Spanish researchers puts the world on notice that
gluten may trigger adverse reactions in both celiacs and non-celiacs alike. The
research team was made up of E. Arranz, D. Bernardo, L. Fernandez-Salazar, J. A.
Garrote and their colleague S. Riestra, all doctors based in
According to the current medical wisdom, innate immunity to gluten
plays a critical role in the development of celiac disease (CD).
innate immune response is caused by a reaction to the ‘toxic’ gluten peptides
that is mediated by interleukin (IL) 15, like the 19-mer through a
DQ2-independent mechanism, and which causes epithelial stress and triggers the
intraepithelial lymphocytes to turn into natural killer (NK)-like cells, which
then causes enterocyte apoptosis and a compromised permeability of the cells
lining of the gut…and, violà, celiac disease!
It is by breaching this
lining that immuno-dominant peptides, such as the 33-mer peptide, come into
contact with the lamina propria, which triggers adaptive immunity.
innate specific response in celiac disease has been pretty well documented, but
until recently, no one had described any differential factors between people
with celiac disease and those without.
Since the toxic 19-mer triggers
its damaging effects through a DQ2-independent mechanism, doctors wondered
whether the innate immune response was common in both people with and without
celiac disease, and whether the adaptive response is emblematic only of
susceptible people with celiac disease.
A team of researchers recently
set out to determine just that, beginning with biopsies from at least three
patients with celiac disease who were observing a gluten-free diet and three
patients who are free of celiac disease. The research team consisted of D.
Bernardo, L. Fernandez-Salazar, J. A. Garrote and their colleague S. Riestra,
all based in Spain.
The team applied crude gliadin, the gliadin synthetic
19-mer and deaminated 33-mer peptides to the biopsy tissue after discarding the
presence of lipopolysaccharide.
They did this at concentrations of 100
mg/ml for 3 hours to mimic what are considered the standard timing and
concentration in the digestive tract after a routine meal.
team then washed the specimens and cultured them for 21 hours in new clean
culture medium to assess whether an innate stimulus is reflected by an adaptive
Here’s some technical jargon:
Each sample cultured in
basal medium served as an internal control. Innate immune mediators IL15 and
nitrites were measured by western blot in the biopsy protein extract along with
a Griess reagent system in the 3 h supernatants respectively. mRNA levels of
adaptive immunity mediators like signal transducers and activators of
transcription (STAT) 1, STAT3, tumour necrosis factor a, interferon (IFN) c,
IL23 (p19), IL27 (p28) and IL12 (p35) were determined by real-time polymerase
chain reaction using b actine levels as house-keeping.
Compared with the
basal culture, all of the patients were challenged with the gliadin solution,
and all of the patients, both those with and those without celiac disease on a
gluten free diet, showed IL15 production, which indicates an immune reaction is
More importantly, the IL15-mediated response in patients
without celiac disease was triggered, in three of six cases, by the same toxic
19-mer gliadin peptide and, in five of six cases, by the 33-mer gliadin peptide
as in those with celiac disease.
Significantly, none of the basal
cultures showed this result, though the ‘‘non-toxic’’ immuno-dominant 33-mer did
induce an innate response that was un-foreseen.
patient with celiac disease and on a gluten-free diet, and three patients
without celiac disease, who were also on gluten-free diets, all showed the IL15
response, which was confirmed by western blot analysis. This discounts an
intracellular and non-biologically active IL15 response in patients without
The gliadin-challenged patients with celiac disease who
were on a GFD, showed increased nitrite levels, which those without celiac
disease did not show. Following the biopsy mRNA isolation, only patients with
celiac disease showed modifications to what are called adaptive mediators
(STAT1, STAT3, IFNc).
The basal samples of those celiac patients on a
gluten-free diet showed
IFNc mRNA levels that were 80 times higher than
basal samples of those without celiac disease (p value 0.002), along with a
slightly higher production of nitrites (p value 0.052).
This appears to
be the first time that researchers have described an IL15-mediated innate
response to gliadin and gliadin peptides in people without celiac disease, as
well as the first time they have described an IL15-mediated innate response to
the ‘non-toxic’ deaminated immuno-dominant 33-mer peptide.
What this all
means is that, for the first time, scientists have documented harmful effects of
gluten on people without celiac disease. This hypothesis seems to be born out by
the fact that all individuals who took place in the study, both those with and
those without celiac disease, showed an innate immune response to gluten, though
only those with celiac disease showed an adaptive immune response to
Clearly, before doctors can draw any hard and fast conclusions,
they will need to do more studies on larger groups.
The research team
also suggests that people with celiac disease have a lower threshold for
triggering an adaptive TH1 response than do non-celiacs, and that people with
celiac disease need to be DQ2 positive.
The reason for the
differences in threshold levels between celiacs and non-celiacs might be tied to
the fact that celiac patients show higher basal levels of immune mediators, such
as IFNc mRNA, compared to those without celiac disease. That’s one
The difference in threshold levels might also have to do
with some kind of defect in permeability of the gut membrane in those with
celiac disease, or even a greater IL15-sensitivity response under equal
stimulus, which might be mediated by a higher density of IL15 receptor in
patients with celiac disease.Gut 2007;56:889–890