Autoimmunity and Arthritis in Youth with Autism and Suspected Post-Infectious Deteriorations

The causes of severe neuropsychiatric deteriorations among patients with previously stable autism spectrum disorder (ASD) are poorly understood and present substantial challenges for care. We aimed to characterize the prevalence of autoimmune and inflammatory conditions and markers, as well as musculoskeletal findings, among youth with ASD experiencing a suspected post-infectious neuropsychiatric deterioration. The Stanford Immune Behavioral Health (IBH) Clinic is a specialty program for youth with neuropsychiatric deteriorations that are suspected to be post-infectious (non-psychosocial). We report findings for 43 consecutive patients with ASD (70% male [30 of 43]) evaluated in the IBH Clinic. The average (SD) age at clinical presentation was 12.0 (4.0) years. Juvenile arthritis was diagnosed in 15 patients (35%), predominantly enthesitis-related arthritis (ERA) and psoriatic arthritis (PsA). Seven patients had ultrasonographic evidence of joint effusions and/or synovitis without meeting juvenile idiopathic arthritis (JIA) criteria. Autoimmune conditions other than arthritis were observed in 9 patients (21%). The mean (SD) age at arthritis and other autoimmune condition diagnoses were 16.2 (5.5) and 12.7 (4.9) years, respectively. We observe markers of immune activation during neuropsychiatric deteriorations in over half of patients (60% [26 of 43]), including markers of autoimmunity (33% [12 of 36]), complement activation (41% [13 of 32]), immune dysregulation/inflammation (11% [4 of 37]), and vasculopathy (30% [13 of 43]). One-third (37% [16 of 43]) demonstrated two or more markers. These data underscore the importance of targeted immune evaluation--including musculoskeletal imaging and inflammatory marker screening--in ASD patients who have had a suspected post-infectious behavioral regression. Lay SummaryIn this cohort study of 43 patients with autism spectrum disorder (ASD) and suspected post-infectious deteriorations, more than half had laboratory markers of immune activation (using a limited panel), one-third had joint inflammation (confirmed by ultrasound), and additional autoimmune conditions were observed in 21%. From this, we conclude that patients with ASD who experience a suspected post-infectious neuropsychiatric deterioration may have underlying inflammation which may contribute to neuropsychiatric and behavioral regressions, highlighting the importance of immunologic and rheumatologic evaluation in clinical assessment.