Distal airway dysbiosis is present in untreated early rheumatoid arthritis (RA) and similar to that detected in sarcoidosis lung inflammation, according to a recent study. This community perturbation, which correlates with local and systemic autoimmune/inflammatory changes, may potentially drive initiation of RA in a proportion of cases. Researchers utilized 16S rRNA gene high-throughput sequencing to compare the bacterial community composition of bronchoalveolar lavage fluid (BAL) in patients with early, disease-modifying anti-rheumatic drugs (DMARD)-naïve RA, patients with lung sarcoidosis, and healthy control subjects. Samples were further assessed for the presence and levels of anti-citrullinated peptide antibodies (including fine specificities) in both BAL and serum. They found:

• The BAL microbiota of RA patients was significantly less diverse and abundant when compared to healthy controls, but similar to sarcoidosis patients.
• This distal airway dysbiosis was attributed to the reduced presence of several genus (ie, Actynomyces and Burkhordelia) as well as reported periodontopathic taxa, including Treponema, Prevotella, and Porphyromonas.