Rescue of STAT3 Function in Hyper-IgE Syndrome Using Adenine Base Editing.

STAT3-hyper IgE syndrome (STAT3-HIES) is a primary immunodeficiency presenting with destructive lung disease along with other symptoms. CRISPR-Cas9-mediated adenine base editors (ABEs) have the potential to correct one of the most common STAT3-HIES causing heterozygous STAT3 mutations (c.1144C>T/p.R382W). As a proof-of-concept, we successfully applied ABEs to correct STAT3 p.R382W in patient fibroblasts and induced pluripotent stem cells (iPSCs). Treated primary STAT3-HIES patient fibroblasts showed a correction efficiency of 29% ± 7% without detectable off-target effects evaluated through whole-genome and high-throughput sequencing. Compared with untreated patient fibroblasts, corrected single-cell clones showed functional rescue of STAT3 signaling with significantly increased STAT3 DNA-binding activity and target gene expression of CCL2 and SOCS3. Patient-derived iPSCs were corrected with an efficiency of 30% ± 6% and differentiated to alveolar organoids showing preserved plasticity in treated cells. In conclusion, our results are supportive for ABE-based gene correction as a potential causative treatment of STAT3-HIES.