Successful treatment of refractory cystitis associated with systemic lupus erythematosus with Belimumab

Lupus cystitis (LC) is a rare manifestation of SLE, the diagnosis of LC is challenging, especially in the absence of other systemic manifestations or the obvious disease activity index of SLE, further cystoscopy and bladder biopsy are crucial. The symptoms of cystitis could be controlled with high-dose GC, but in the process of GC reduction, the condition repeated. Here we report one case of refractory LC treated with Belimumab. The case is a 45-year-old female patient who had SLE and presented with urinary urgency, frequency and pain for more than 3 years. Laboratory assays revealed high ANA, reduced complement 3 level, proteinuria, significantly elevated Leukocyte esterase and leukocyte in urine, with the negative urinary culture of bacteria and mycoplasma, meanwhile, the cystoscopy and bladder biopsy showed interstitial inflammation. Confirming the diagnosis of refractory SLE-LC, recommended-dose Belimumab (10 mg/kg fortnightly for 3 times, monthly for 6 times) was administered, resulting in the normalization of urinary activity and significant reductions in leukocyte counts and protein levels of urine. No lupus cystitis relapse or SLE activity occurred during 10 months of follow-up. Our case confirmed the efficacy and good follow-up outcomes of Belimumab treatment for refractory SLE-LC.