Harnessing and Re-Engineering AAVrh32.33: From Skin Tropism to Immune-Evasive Vector Design

Skin diseases are highly prevalent, yet many remain without durable therapeutic options. While recent advances have introduced gene therapy as a promising alternative, adeno associated virus, one of the most successful gene therapy platforms to date, has not been fully explored for skin-targeted delivery. Here, we found that AAVrh32.33 exhibits a strong and previously unrecognized ability to target the skin. Systemic administration in mice resulted in efficient transduction of dermal fibroblasts and hair follicle bulge stem cells, two long-lived compartments capable of supporting sustained expression. AAVrh32.33-mediated transgene expression persisted for up to two years following a single injection. To reduce the known immunogenicity of AAVrh32.33, we modified the capsid by disrupting a dominant CD8⁺ T-cell epitope (IDPΔ), which diminished peptide-specific responses while preserving dermal tropism. In human skin explants, the IDPΔ variant also transduced stromal cells effectively, with expression primarily in dermal fibroblasts and fibroblast-lineage precursors, underscoring its translational relevance. Systemic administration of chemokine-encoding vectors resulted in localized expression in healthy skin as well as in the atopic dermatitis (AD) mouse model, while avoiding major systemic alterations, demonstrating that this platform can deliver immune-modulating genes directly to diseased skin without broad off-target effects. Together, these findings establish AAVrh32.33 and its IDPΔ variant as promising platforms for durable gene delivery to the skin, enabling targeted modulation of cutaneous immune pathways and offering relevance for conditions such as vitiligo, AD, and primary cicatricial alopecia where long-term reshaping of the dermal microenvironment is critical.