Abstracts

Rationale: Rituximab is an anti-CD20 chimeric monoclonal antibody that results in B-cell depletion. We aimed to determine the efficacy of rituximab treatment as a second-line immunotherapy of autoimmune limbic encephalitis (ALE) and to determine factors associated with functional improvement and favorable outcome.Methods: From March 2012 to October 2014, seventy-five ALE patients (39 men, 36 women; mean age, of 42.5±18.5years [range 16-80 years]) with median rituximab cycle of 5 (interquartile range [IQR] 4–7), were followed-up for 22.0±12.3months (range 9-36 months). Thirty were included in the surface autoantibody group (anti-NMDAR 27, LGI1 3), 20 in the intracellular autoantibody group (anti-GAD 10, amphiphysin 3, Hu 2, Yo, 2 Ma2/Ta 3), and 25 in the no proven antibody group with typical AE syndrome.Results: Rituximab was effective in all subgroups, regardless of the detection of autoantibodies or the types of detected autoantibodies. Additional monthly rituximab therapy and partial responsiveness to first-line immunotherapies were both associated with outcome improvement and favorable outcome. Poor mRS at neurological nadir was a predictor of a poor functional outcome. Demographic factors, detection or category of autoantibody, tumor association, laboratory factors, and profiles of first-line immunotherapy did not show significant association with outcomes. Infusion related side effect and consequent withdrawal of rituximab was reported in 2 (2.7%) patients and infection related side effect and consequent withdrawal of rituximab was reported in 2 (2.7%) patients.Conclusions: Rituximab is effective and safe in ALE as a second-line immunotherapy, regardless of the detection of autoantibodies or the types of detected autoantibodies. Partial responsiveness to first-line immunotherapies might predict clinical improvement after rituximab therapy. Additional monthly rituximab therapy might potentiate the efficacy of rituximab.