Three cases with chronic obsessive compulsive disorder report gains in wellbeing and function following rituximab treatment

Abstract Obsessive compulsive disorder (OCD) is a debilitating condition affecting about 2% of the population where half of patients do not respond to standard treatment. The emerging concept of an autoimmune OCD subgroup is grounded on findings that suggest immunological aetiology. We here present the longitudinal clinical course for three severely ill, functionally impaired complex cases with chronic treatment-resistant OCD. In all three cases, off-label treatment with rituximab was followed by clear and sustained gains regarding symptom burden and function over several years. The clinical phenotypes and clinical red flags are described in detail. Antibodies targeting mouse brain tissue were detected in cerebral spinal fluid for all three cases. We report exploratory analyses of immunological markers and proteomics and findings include elevated levels of sCD27 and markers indicative for complement pathway activation in CSF when compared to controls. Multidisciplinary collaboration, advanced clinical investigations and rituximab treatment are feasible in a psychiatric setting. The case histories provide a proof of principle for the newly proposed criteria for autoimmune OCD. The findings suggest that clinical red flags and biological measures may predict rituximab response in chronic treatment-resistant OCD. The report provides orientation that may inform the hypotheses and design of future treatment trials.