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màj 23/07/98 |
Report
by Micaela Romagnoli on the following session :
Samedi 14 Février 1998
|
Présentateurs
|
Modérateurs
|
Experts
|
9h30-10h30
|
Marqueurs de l'inflamation
|
P. Deviller
(Lyon)
I.
Vachier (Montpellier)
I.
Pin (Grenoble)
Discussion
|
10'
10' 10' 30'
|
M.
Fournier (Paris)
B. Crestani (Paris)
|
S.E.
Dahlen (Stockholm, S)
K. Richter (Grossandorf, D)
|
P. Deviller (Lyon)
: has studied a way to assay
the eosinophilic inflammation in urines. He specially
studied Carrington's disease and Churg-Strauss syndrome.
He explained us that among 4 different cationic proteins
found in blood, only one was able to be excreted in
urines. The main advantage to analyse urines is that is a safe
and easy avaible method to collect human sample.
Dr Deviller showed that the correlation found
between urinary EDN and blood eosinophils was not the same for
all pathologies
studied. At the present time there are only three studies
published on the EDN as compared to a large number of
studies on ECP in serum. Further more studies might
showed that measurements of urinary EDN should be a
simple way to study eosinophilc inflammation.
|
Discussion:
Pr Dahlen stated that it was
important to have the opportunity to study metabolites in urines.
He asked about the mechanism by which EDN was transported in
blood and how it was eliminated
in urines by filtration or excretion.
Dr Deviller has no precise
answer on these two points. 95% of EDN is reabsorbed by the renal
tubule.
There are no diurnal variation of
urinary EDN as it was found for blood eosinophils, so EDN would better reflect the persistant
stage of eosinophil degranulation in tissue during a period, than
did ponctual measurement of blood eosinophils. Dr Deviller
hypothesised that EDN will be
associated to tissue eosinophils apoptosis.
Dr Crestani asked the question if
any experiments have been done to evaluate the effect of
corticosteroids on the production of EDN.
Dr Deviller has no data, he did not notice any diffrence in
patients he studied with different treatments.
Dr Richter asked for any data on
asthma and treatment.
Dr Vachier comments on the study they have done on the measurements of urinary EDN on asthmatic patients,
untreated versus steroid-dependent .Urines from steroid-dependent
asthmatic patients have still high levels of EDN, without significant difference with
untreated asthmatics.
I. Vachier (Montpellier) : In
this study, a group of severe persistant asthmatic patients
requiring oral and inhaled permanent treatment with steroids, was
compared to a group of mild to moderate asthmatics, without any
treatment and a group of healthy subjects.
The aim of the study was to
compare in the 2 groups of patients the production of
leukotrienes, HETEs and
lipoxins from isolated and purified blood monocytes, neutrophils
and alveolar macrophages obtained from BAL. Cells were stimulated
with Ca Ionophore with and without additional metabolites.
Leukotriene levels were detected in biological fluids
such as supernatants of induced sputum and urines.
The author hightlighted the surprising and
controversal aspect of the result, concluding that stimulated
cells of long term steroid treated patients release very low
levels of leukotrienes, wheras increased levels were found in
biological fluids, despite steroid treatment. As Dr Vachier have found that 5-LO was
still present in the cells, the hypothesis is that long-term steroid treatment might modify the
structure of the membrane, and the stimulation with Calcium
Ionophore may reflect this.
Discussion:
Prof Dahlen highlight the fact
that all experiments were performed using HPLC, which is the best method for identify
leukotrienes. He asked the reason why there was a difference between in vitro and in vivo
results.
Dr Vachier confirmed the hypothesis of the effect of long-term
steroid treatment on the structure of the membrane and suggest
also the possibility of lower levels of arachidonic acid
disponibility.
Then Prof Dahlen asked if other stimuli have
been used and Dr Vachier answered that exogenous arachidonic acid
was used and it was not able to retrieve 5-LO activity.
Prof Fabbri asked if the author
had preliminary data on leukotriene levels in weaned patient. Dr
Vachier answered that they have some data in 5 patients but the
results were very variable concerning the time for retrieve a
normal level release.
Dr Crestani asked for any results
on the stimulation of Calcium-Ionophore on epithelial cells. Dr Vachier stated
that they have data on epithelial cells releasing 15-HETE, but no
data on steroid-dependent asthmatic patients.
I. Pin
(Grenoble) : Sputum induction represents a method of
direct assessment in asthmatic patients. It is a simple and safe
method and the quality of samples is based on volume of
secretions and contamination of squamous cells and adequate
sample are obtained in 50 to 70% of cases. There are some
different methods of sputum processing. The selected technique
might lead to loss potential information. Processing all sample,
including saliva cause dilution and contamination.
Sputum induction is a
reproducible method. Moreover characteristics of induced sputum
are very closed to spontaneous sputum. In comparison to methods
of direct assessment in asthmatics, sputum induced cellular-composition seems closer to bronchial wash
than BAL, but there is poor correlation with bronchial biopsies.
Exacerbations of asthma induced
by a decrease in the dose of inhaled steroids are usually
associated with increase of eosinophils, whereas there are some
data of increasing neutrophils in "wild" exacerbations,
the meaning of that is unknown.
In conclusion sputum induction
presents many advantages, but it has some limitations, such as
failure of induction, time consuming, the problem of the use in
children and the experience to do it.
Discussion:
Prof Fournier asked the opinion
of Dr Pin about the finding of neutrophils in "wild"
exacerbations. She answered that she is not sure if the presence
of bacteria was evaluated. There are some data about viral
infection by rhinovirus and eosinophils in sputum in Dr Sterk's
group.
Dr Jonhston commented that he has
no data in sputum.
Prof Fabbri asked about the
variability of reproducibility of the test in litterature and
highlighted the necessity of meta-analysis on this point.Then he
asked about the effect of steroids during exacerbations on sputum
induced cells and the author answered that data from Dr
Pizzichini demonstrated a slow drop in eosinophils in patients
with predominant eosinophilic inflammation, but no improvement
was observed in patients with high levels of neutrophils in
induced sputum.
The discussion was then about the
origin of neutrophils found in sputum among Dr Richter, Prof
Chung and Dr Vignola; no clear conclusion was given.
. 
Enfumosa Congrès Conçue et réalisée par: Michel Godard (at) Top
Date de création: 12 Février 1998 -Dernière mise à jour: 23/07/98
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