Safety and diagnostic utility of brain biopsy and metagenomics in decision-making for patients with inborn errors of immunity (IEI) and unexplained neurological manifestations

Retrospective analysis of clinical and diagnostic data on paediatric patients with inborn errors of immunity who had a brain biopsy between 2010 and 2022 at a UK tertiary centre. We found that brain biopsy enabled diagnostics with manageable complications in the majority of cases, either by tissue or metagenomics analysis (n=11/14, 79%). We found that mNGS analysis increased the diagnostic yield of brain biopsy and even where it was negative, mNGS facilitated diagnosis.