https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11255363/pdf/main.pdf
Chronic obstructive pulmonary disease (COPD) and bronchiectasis
are two different diseases with overlapping clinical presentation.
Patients are frequently diagnosed with both diseases,
and this is termed COPD-bronchiectasis association.
Huang et al.28 recently demonstrated that patients with COPD and
COPD- bronchiectasis association presented different profiles
in their lung microbiota and host responses.
Lung microbiota of the latter group was closer to that of bronchiectasis
patients. The authors suggested classifying patients with COPD,
bronchiectasis and COPD-bronchiectasis association into 5 different
endotypes according to their clinical, sputum microbiome and
protein profiles, which may present treatable traits.
-The first proposed endotype is the diverse-protective endotype,
which has the best prognosis.
-Second, the Haemophilus-proteolytic endotype is associated with Haemophilus
infection,for which tetracyclines could be a theoretical treatment option.
-Third, the infected-epithelial response endotype has characteristics
of bronchiectasis patients, such as gram-negative infection, and may
benefit from macrolide treatment.
-Fourth is the proteobacteria-neutrophilic endotype, in which macrolides
may also be beneficial, as this group also has similarities with
bronchiectasis and excessive neutrophil activation with the formation
of NETs.
-Finally, the Th2 endotype responds to inhaled corticosteroids (ICS) or
other treatments targeting Th2 inflammation.29

{Th2 =? T2-high : eosinophilic , high FENO}