scRNA-Seq Reveals Sustained Pro-Inflammation by Innate Immune Activation in In Utero HBV-Exposed Neonates of High...

High levels of HBV DNA and HBsAg titres increase the risk of mother-to-child transmission. Development of adaptive immunity post HBV vaccination in neonates born to HBsAg-positive mothers may be determined by maternal HBsAg titres. We analysed pre- and post-HBV vaccination immune status in neonates.

PBMCs were collected before and after vaccination for single cell multi-omics sequencing for infants born to mothers with low (Gr.1, sAg^Lo 1.65 × 10² IU/mL) and high (Gr.2, sAg^Hi 1.4 × 10⁴IU/mL) HBsAg titres. Integrative analysis of whole transcriptome and surface marker expression was done using the Seurat R package. Functional validation of single-cell data was performed through immunophenotyping in both groups.

scRNAseq revealed that, at pre-HBV vaccine, CD8⁺T cells of neonates born to mothers with HBsAg^Hi levels showed increased expression (p < 0.05) of TOX, CTLA4, PD1, LAG3, CD38 and CREM exhaustion markers and decreased expression of ATP1B3, MREG and TGFβ1 compared to sAg^Lo. Monocytes and NK cells had elevated CXCR3, TNFSF9, HIVEP3, WDPCP, ATP6V1G2, IL-6, GMCSF and GCSF (p < 0.0001) driving the inflammation and mitochondrial biogenesis through MAP/ERK kinase in sAg^Hi compared to sAg^Lo. Post-vaccination, despite anti-HBs titre ≥ 10 IU/mL, sAg^Hi, neonates showed persistently high TOX, CTLA4, PD1 and CREM in CD8⁺T cells (p < 0.0001). Functional validations by immune phenotyping also showed higher expression of LAG3, PD1, TIGIT and BTLA (p < 0.05) on CD8⁺T cells pre- and post-vaccination in sAg^Hi compared to sAg^Lo.

HBV exposure compromises adaptive immunity at birth; despite post-vaccination anti-HBs titres generation, there was a sustained pro-inflammatory state by the innate immune activation via metabolic alterations that persisted in neonates born to sAg^Hi mothers.