Ongphichetmetha, Tatchaporn

ABSTRACTClinicians often repeat aquaporin‐4‐immunoglobulin G (AQP4‐IgG) testing in case of possible seroconversion. Compared with older, less sensitive immunofluorescence assays (IFA), cell‐based assays (CBA) offer higher sensitivity. This study assessed the frequency of seroconversion in a retrospective Cleveland Clinic cohort (2006–2024) of 451 patients with an initial negative AQP4‐IgG result who underwent serial testing. Seroconversion occurred in 4.3% (7/170) of patients initially tested by tissue IFA, but in none (0/263) of those tested by CBA. The lack of AQP4‐IgG seroconversion after a negative CBA, with only rare cases after a negative IFA, suggests that repeat AQP4‐IgG testing is low yield unless prior testing used older methods such as IFA.

ABSTRACTObjectiveClinical outcome measures for autoimmune encephalitis (AE) are not yet well defined. Cognitive outcome measures (CogOs) and patient‐reported outcomes (PROs) may capture the symptoms of AE, beyond clinician‐reported outcomes (ClinROs) (the Modified Rankin Scale [mRS] and Clinical Assessment Scale in Autoimmune Encephalitis [CASE]).MethodsThis retrospective cohort study examined LGI‐1‐IgG AE patients at Cleveland Clinic. CogOs included the Rey Auditory Verbal Learning Test (RAVLT) and Brief Visuospatial Memory Test (BVMT). PROs included Neuro‐QoL, PROMIS Global Physical (GPH) and Mental Health (GMH). Abnormal RAVLT, BVMT (≤ −1.5 SD), Neuro‐QoL, and PROMIS (≥ 10 T‐scores) proportions were analyzed. CogOs and PROs were correlated with ClinROs using Spearman's rank correlation.ResultsForty‐four patients (64% male, mean age 68 [SD = 11], median follow‐up 19 months) were included. ClinROs improved, with median mRS decreasing from 2.5 (IQR = 2–3) to 2 (IQR = 1–2), and CASE from 5 (IQR = 3–6) to 3 (IQR = 2–3) (all p < 0.05). RAVLT (n = 15), BVMT (n = 16), Neuro‐QoL (n = 21), and PROMIS (n = 34) were available. At > 12 months from diagnosis, cognition was impaired on BVMT (56%) and RAVLT (20%). PROs showed impairments in Neuro‐QoL lower (38%) and upper (27%) extremity function, cognition (31%), and PROMIS‐GPH (25%). RAVLT correlated with Neuro‐QoL cognition, depression, and stigma, while BVMT correlated with PROMIS‐GMH (all unadjusted p < 0.05). Neither RAVLT nor BVMT correlated with ClinROs. ClinROs correlated with Neuro‐QoL lower extremity function, cognition, and social roles (all p < 0.05).InterpretationLGI‐1‐IgG AE patients have long‐term impairments in cognition, physical health, and social roles, which can be objectively measured using CogOs and PROs and are not captured by ClinROs.