FROM ARTHRITIS & RHEUMATOLOGY
In bronchiectasis patients who develop rheumatoid arthritis, the responses of anticitrullinated peptide antibodies become more citrulline specific, according to results of a British study.
The study investigators measured anticitrullinated peptide antibodies (ACPA) and rheumatoid factors (RF) in 122 patients with bronchiectasis (BR) alone, 50 patients with BR and RA (BRRA), 50 patients with RA without lung disease, 87 patients with asthma, and 79 healthy patients.
The citrulline specificity of ACPA in patients with BRRA was increased, compared with patients with BR alone and RA without any lung disease. While the study showed significantly elevated levels of ACPA in patients with BR alone, the ACPA response was not citrulline specific.
“Bronchiectasis is an unusual but potent model for the induction of autoimmunity in RA by bacterial infection in the lung,” according to Anne-Marie Quirke, Ph.D., and her colleagues. “Our study suggests that in the early stages of tolerance breakdown, the ACPA response is not citrulline specific, but becomes more so in those patients with BR that develop BRRA.”
In contrast to patients with BR alone, patients with BRRA showed no correlation between antibody responses to citrullinated peptides and arginine-containing peptides, with the exception of the citrullinated peptide cVim and the arginine-containing peptide Vim.
Rheumatoid factors were found significantly more often in BRRA patients, compared with patients with RA without any lung disease, with percent serum antibody positivity for RF vs. controls having been 82 and 52, respectively. For patients with BR alone, the percent serum positivity of RF, compared with controls, was 25.
“Further prospective investigations will need to be carried out of BR patients at risk for RA in order to confirm the evolution of citrulline specificity of ACPA in patients with BR who subsequently develop [RA],” according to the researchers.
Read the full study in Arthritis & Rheumatology (doi:10.1002/art.39226).
