Abstracts

Rationale: Dysregulation between regulatory T cells (Tregs) and effector T cells is thought to be involved in most autoimmune diseases. Modulation of Tregs number and function by providing more interleukin-2 (IL-2) dependent signaling may help correct disease. We aimed to determine the possibility of low dose IL-2 as a treatment for refractory autoimmune encephalitis (AE). Methods: We selected patients who had inadequate clinical response to first- and second-line standard regimen and received at least four-cycle of low dose IL-2 from our institutional cohort. We evaluated clinical, laboratory, and immunotherapy profiles and improvement of modified Rankin-Scale (mRS) score at the last follow-up from the initiation of low dose IL-2 treatment as main outcome. The safety of the administration of low dose IL-2 was also investigated. Results: Ten patients were retrospectively identified. Autoantobidies were detected in four patients. All the patients had seizures, seven (70%) had psychiatric features, six (60%) had memory dysfunction, and four (40%) had language dysfunction.Patients received low-dose IL-2; one course of subcutaneous IL-2 (1.5 million IU/day) for 5 days, followed by three 5-day courses of 3 million IU/day at weeks 3, 6, and 9. We observed an improvement of mRS scores at last follow-up in six patients compared to those at the initiation of low dose IL-2. (p = 0.014) One patient had grade 3 neutropenia. Conclusions: Low-dose IL-2 is a feasible and relatively safe for the treatment of AE who is refractory to first-line treatment and the second-line immunotherapy. Funding: None