Page 86 - Škrgat, Sabina, ed. 2022. Severe Asthma - Basic and Clinical Views. Koper: University of Primorska Press. Severe Asthma Forum, 1
P. 86
of asthma27. Nevertheless, with the advent of n otably increased risk of severe exacerbations
targeted asthma therapy, it gained a key role in the year preceding FeNO measurement38.
severe asthma forum 1: severe asthma - basic and clinical views in tailoring individual therapy as well as mon-
itoring its effectiveness. Depending on blood A recent study by Brooks, Massanari,
levels, total IgE may also indicate other co- Hanania and Weiner found that the imple-
morbidities (including allergic bronchopul- mentation of FeNO into pre-omalizumab
monary aspergillosis, certain primary im- treatment assessment decreases the expected
munodeficiencies, infections and infestations per-patient cost by almost 50% from the mo-
(parasites), inflammatory diseases, and ma- ment of omalizumab initiation into therapy,
lignancies)28. and the same trend continues during the first
year of the omalizumab treatment. Authors
Fractional Exhaled Nitric Oxide point to the obvious benefit of using FeNO
Concentration (FeNO) for detecting omalizumab responders (prior
to initiating a 12-week trial of omalizumab)39.
Fractional exhaled Nitric Oxide (FeNO) is
used to detect active airway eosinophilic in- Induced Sputum and Airway Inflammation
flammation, measured by solely non-invasive
tests35. Studies have demonstrated the usefulness of
induced sputum to guide asthma treatment
Due to its immense importance in the and showed that normalizing airway eosino-
differential diagnostic process, fractional ex- philic inflammation allowed better control of
haled nitric oxide concentration (FeNO) has asthma with reduced exacerbations and hos-
a distinctive role among all biomarkers. Ni- pital admissions29. The technique of induced
tric oxide (NO) is normally found in exhaled sputum that allows non-invasive collection
breath while patients with asthma often ex- of airway cells is considered the gold stand-
hibit higher levels of NO in their exhaled ard to identify inflammatory asthma phe-
breath, which is thought to be due to the up- notype30. In one study performed using in-
regulation of inducible nitric oxide synthase duced sputum, it was shown that compared
(NOS2) in airway epithelial cells, the enzyme to the paucigranulocytic phenotype, eosino-
in charge of epithelial NO production36. Giv- philic, neutrophilic and mixed granulocyt-
en that NO levels can be measured relative- ic phenotypes were characterised by a poorer
ly easily, and the test itself is non-invasive and lung function. Eosinophilic phenotype exhib-
easily repeatable, FeNO has enormous poten- ited a higher frequency of atopy, higher lev-
tial in everyday clinical practice. els of IgE, higher bronchial hyperresponsive-
ness to methacholine, higher FeNO levels and
The American Thoracic Society recom- lower asthma control compared to paucigran-
mends clinically significant cut-off points for ulocytic. The mixed granulocytic phenotype
FeNO: (1) <25 ppb (<20 ppb in children), and had higher levels of fibrinogen, the lowest lung
(2) >50 ppb (>35 ppb in children)37. function and the highest degree of bronchi-
al hyperresponsiveness to methacholine31. As
FeNO is a biomarker of T2 response (or far as the sputum neutrophilic phenotype is
airway eosinophilia) but does not correlate concerned, there was a weak correlation be-
with sputum eosinophils. A FeNO level >50 tween sputum and blood neutrophil count
ppb suggests a steroid-responsive inflamma- taken in percentage. In a study conducted by
tion, while patients with a FeNO level around Ntontsi et al., it was found that paucigranu-
25 ppb are less likely to respond to steroids37. locytic asthma was most likely to be a benign
asthma type, related to good treatment re-
A recent study by Price et al., found that sponse32. Smokers did not have a significantly
people with a combination of high FeNO
and high blood eosinophils were prone to a
targeted asthma therapy, it gained a key role in the year preceding FeNO measurement38.
severe asthma forum 1: severe asthma - basic and clinical views in tailoring individual therapy as well as mon-
itoring its effectiveness. Depending on blood A recent study by Brooks, Massanari,
levels, total IgE may also indicate other co- Hanania and Weiner found that the imple-
morbidities (including allergic bronchopul- mentation of FeNO into pre-omalizumab
monary aspergillosis, certain primary im- treatment assessment decreases the expected
munodeficiencies, infections and infestations per-patient cost by almost 50% from the mo-
(parasites), inflammatory diseases, and ma- ment of omalizumab initiation into therapy,
lignancies)28. and the same trend continues during the first
year of the omalizumab treatment. Authors
Fractional Exhaled Nitric Oxide point to the obvious benefit of using FeNO
Concentration (FeNO) for detecting omalizumab responders (prior
to initiating a 12-week trial of omalizumab)39.
Fractional exhaled Nitric Oxide (FeNO) is
used to detect active airway eosinophilic in- Induced Sputum and Airway Inflammation
flammation, measured by solely non-invasive
tests35. Studies have demonstrated the usefulness of
induced sputum to guide asthma treatment
Due to its immense importance in the and showed that normalizing airway eosino-
differential diagnostic process, fractional ex- philic inflammation allowed better control of
haled nitric oxide concentration (FeNO) has asthma with reduced exacerbations and hos-
a distinctive role among all biomarkers. Ni- pital admissions29. The technique of induced
tric oxide (NO) is normally found in exhaled sputum that allows non-invasive collection
breath while patients with asthma often ex- of airway cells is considered the gold stand-
hibit higher levels of NO in their exhaled ard to identify inflammatory asthma phe-
breath, which is thought to be due to the up- notype30. In one study performed using in-
regulation of inducible nitric oxide synthase duced sputum, it was shown that compared
(NOS2) in airway epithelial cells, the enzyme to the paucigranulocytic phenotype, eosino-
in charge of epithelial NO production36. Giv- philic, neutrophilic and mixed granulocyt-
en that NO levels can be measured relative- ic phenotypes were characterised by a poorer
ly easily, and the test itself is non-invasive and lung function. Eosinophilic phenotype exhib-
easily repeatable, FeNO has enormous poten- ited a higher frequency of atopy, higher lev-
tial in everyday clinical practice. els of IgE, higher bronchial hyperresponsive-
ness to methacholine, higher FeNO levels and
The American Thoracic Society recom- lower asthma control compared to paucigran-
mends clinically significant cut-off points for ulocytic. The mixed granulocytic phenotype
FeNO: (1) <25 ppb (<20 ppb in children), and had higher levels of fibrinogen, the lowest lung
(2) >50 ppb (>35 ppb in children)37. function and the highest degree of bronchi-
al hyperresponsiveness to methacholine31. As
FeNO is a biomarker of T2 response (or far as the sputum neutrophilic phenotype is
airway eosinophilia) but does not correlate concerned, there was a weak correlation be-
with sputum eosinophils. A FeNO level >50 tween sputum and blood neutrophil count
ppb suggests a steroid-responsive inflamma- taken in percentage. In a study conducted by
tion, while patients with a FeNO level around Ntontsi et al., it was found that paucigranu-
25 ppb are less likely to respond to steroids37. locytic asthma was most likely to be a benign
asthma type, related to good treatment re-
A recent study by Price et al., found that sponse32. Smokers did not have a significantly
people with a combination of high FeNO
and high blood eosinophils were prone to a
