Nontuberculous mycobacterium seroprevalence in Japanese patients with RA

Although newly developed immunosuppressive therapies have markedly enhanced disease control in patients with RA, they are associated with an increased risk of various infections, including nontuberculous mycobacterial (NTM) disease and tuberculosis (TB). The anti-glycopeptidolipid (GPL) antibody (Ab) test is used to screen for NTM disease, and the interferon-gamma release assay (IGRA) is used to screen for TB. However, detailed analyses of positive anti-GPL Ab test results from RA patients remain scarce. Therefore, this study examined anti-GPL Ab testing and IGRA positivity in RA patients to determine whether NTM or TB are increased in RA patients.

Clinical information of Japanese RA patients who underwent anti-GPL Ab testing from 2015 to 2023 or IGRA from 2013 to 2023 was analysed.

The positivity rates of anti-GPL Ab testing were higher in female RA (P = 0.0211) and older RA (P = 0.0050) patients, and increased with time (P = 8.61 × 10^-8). The positivity rates of anti-GPL Ab testing in younger female RA patients showed a trend towards being increased. The positivity rates of IGRA decreased with time (P = 0.0015).

The positivity rates of anti-GPL Ab testing increased with time in RA patients and were higher in older RA or younger female RA patients, suggesting the increasing incidences of NTM diseases in Japanese RA patients. The positivity rates of IGRA decreased with time in RA patients.