Bronchiectasis is commonly found in patients with autoimmune conditions, causing blood vessel inflammation, a recent study found.
Moreover, the presence of bronchiectasis in these patients is linked to specific disease features, raising the possibility that these autoimmune diseases may be triggered by respiratory tract conditions, researchers argued in the journal Seminars in Arthritis and Rheumatism.
The study, “Bronchiectasis is highly prevalent in anti-MPO ANCA-associated vasculitis and is associated with a distinct disease presentation,” was performed by researchers at Nantes University Hospital and INSERM in France.
Granulomatosis with polyangiitis (GPA) or microscopic polyangiitis (MPA) are two forms of blood vessel inflammation linked to so-called ANCA autoantibodies. These antibodies target two proteins known as PR3 and MPO, ultimately resulting in organ damage.
Patients with GPA often have respiratory problems before apparent blood vessel inflammation, but MPA-affected patients also develop respiratory disease.
Earlier studies suggest that many patients with ANCA vasculitis have bronchiectasis, but it is not yet clear how presence of the lung condition impacts the autoimmune disease.
To explore this, researchers recruited 58 Caucasian patients with ANCA vasculitis; 28 had GPA-type disease and 30 had MPA.
Among the patients, 67.2 percent had anti-MPO antibodies and 32.8 percent had anti-PR3 antibodies.
Twenty-two of the patients (37.9 percent) had bronchiectasis. All of these affected patients had anti-MPO ANCA antibodies. In the group with anti-MPO antibodies, 56.4 percent had imaging evidence of bronchiectasis and another four had bronchiectasis symptoms.
Patients with lung disease more often had symptoms of peripheral nervous system and movement impairment compared to those without bronchiectasis. On the other hand, they were less likely to have kidney disease. In fact, they had better kidney function than patients without bronchiectasis, despite being older.
Statistical analysis revealed that bronchiectasis was linked to anti-MPO antibodies, female sex and age at the time of ANCA vasculitis diagnosis.
Patients with bronchiectasis, however, did have a similar disease course and risk of severe lung infection as those without the condition. Survival rates also were not dependent on bronchiectasis.
The data indicates that the autoimmune processes in ANCA vasculitis may start in the respiratory system, at least in a subset of patients, researchers said.
“This study shows that bronchiectasis is a highly prevalent pre-existing respiratory condition in Caucasian patients with anti-MPO AAV [ANCA-associated vasculitis]. This subset of patients exhibits a distinct presentation.” the team wrote.
More studies are now needed to explore how bronchiectasis may impact disease processes in ANCA vasculitis patients, and “whether the respiratory tract could be the site of initiation of anti-MPO auto-immunity” the researchers concluded.