Retention rate and long-term safety of biosimilar CT-P13 in patients with ankylosing spondylitis: data from the Korean College of Rheumatology Biologics registry.

A 51-year-old woman with rheumatoid arthritis treated with rituximab and leflunomide presented with a 5-month history of malodorous vaginal discharge. Initial examination revealed vulvovaginitis and cervicitis, and she was treated with metronidazole and topical corticosteroids. Pelvic ultrasound showed free fluid in the pouch of Douglas, raising suspicion of ovarian malignancy. Shortly thereafter, she was hospitalized with fever, abdominal pain, and elevated C-reactive protein. Despite broad-spectrum intravenous antibiotics and multiple surgical drainages for recurrent intra-abdominal abscesses, the infection persisted, and repeated cultures were negative. Corticosteroids led to transient improvement, but new abscesses developed despite immunosuppressive therapy, and an aseptic abscess syndrome was suspected. Given her immunosuppressed status, further testing was undertaken, and polymerase chain reaction (PCR) analyses from urine, vaginal secretions, synovial fluid, and paraspinal abscess aspirate were positive for Ureaplasma parvum, for which her partner also tested positive. Treatment with oral doxycycline led to rapid clinical and laboratory test improvement, and moxifloxacin was added for bactericidal coverage. Because of mild hypogammaglobulinemia, monthly intravenous immunoglobulin therapy was initiated. This case illustrates the diagnostic challenges of Ureaplasma infections in immunocompromised patients, particularly those receiving B-cell-depleting therapy such as rituximab. Standard cultures fail to detect the organism, often delaying diagnosis. Ureaplasma parvum should therefore be considered in patients presenting with sterile abscesses, systemic inflammation, and urogenital symptoms. Early recognition through molecular testing and targeted antimicrobial treatment can prevent prolonged morbidity and unnecessary surgical interventions.