Analysis of Influences of Sjögren's Disease and Anti-Ro/SS-A Antibodies on Clinical Course of Patients with Rheumatoid Arthritis Complicated by Lymphoproliferative Disorders: A Pilot Study.

Background/Objectives: Lymphoproliferative disorders (LPDs) are adverse effects of methotrexate (MTX) prescribed for rheumatoid arthritis (RA). Sjögren's disease (SjD), for which the presence of anti-Ro/SS-A antibodies (Abs) is a diagnostic criterion, might accompany RA and be a risk factor for LPDs. We conducted a retrospective study to analyze the effects of SjD or anti-Ro/SS-A Ab positivity on the clinical course of patients with RA complicated by LPDs. Methods: We retrospectively analyzed 25 patients in our department who had RA complicated by LPDs, specifically collecting clinical information regarding the complications of SjD and positivity for anti-Ro/SS-A Abs. Results: In total, 25 patients with RA were included in this study, 3 of which were diagnosed with SjD by attending physicians based on sicca symptoms and positiveness of anti-Ro/SS-A antibodies. No significant differences in clinical characteristics except for SjD diagnosis given by attending physicians were found between the patients positive for anti-Ro/SS-A Abs and the patients negative for anti-Ro/SS-A Ab. The most common histologic LPD subtype was diffuse large B cell lymphoma, while mucosa-associated lymphoid tissue lymphoma, the histologic subtype often diagnosed as SjD-LPD, was found in only one patient, who was positive for anti-Ro/SS-A Abs without an SjD diagnosis. There were no significant differences in the intervals between the RA and LPD diagnoses and those of SjD and anti-Ro/SS-A Ab positivity. Conclusions: While the rate of anti-Ro/SS-A Ab positivity in the study population seemed to be higher than that in the general RA population, any potential effects of SjD on RA-LPD development were not ascertained in this study.