We found 14 symptomatic and 1 asymptomatic patient with CSF1-related leukoencephalopathy treated with HSCT. The median age of symptomatic disease onset was 39 (range 32-50 years), with cognitive impairment being the most common initial manifestation (43% of patients). Cognitive decline and gait problems were the predominant symptoms in most patients (37% each). The median disease duration before HSCT was 24 months (range 11-144 months). The median follow-up post-HSCT was 26 months (range 3-180 months). Cognition, neuropsychiatric, extrapyramidal, pyramidal symptoms, gait, and seizures, deteriorated in 6, 5, 6, 3, 4, and 1 patients, respectively. Improvement or no change in cognition, neuropsychiatric, extrapyramidal, pyramidal symptoms, gait, and seizures, was observed in 9, 10, 7, 9, 11, and 10 patients, respectively. One patient died 88 days after the HSCT. Three patients remained professionally active, and five were independent in activities of daily living during post-HSCT follow-up. Further statistical calculations were underway at the moment of submitting the abstract.

CSF1R-related leukoencephalopathy is a devastating disease and HSCT is a major procedure with potentially life-threatening complications. Therefore it is of paramount importance to determine the predictors of good and bad outcomes and find the best candidates for the therapy with HSCT.