Single-cell and repertoire profiling reveals immune remodelling in paediatric upper airway: insights from adenoid...

To characterise the immune cellular landscape and paired B-cell and T-cell receptor repertoires of hypertrophic adenoids in children with obstructive sleep apnoea.

We performed 10x Genomics 5' single-cell RNA sequencing with paired V(D)J profiling on adenoid tissues from children (AH, n = 4; control, n = 4) and analysed 72 076 high-quality cells.

Compared with controls, AH adenoids exhibited an expanded B-cell compartment (62.26% vs 51.94%, P = 0.029) and a modest increase in plasmacytoid dendritic cells (0.37% vs 0.15%, P = 0.029), accompanied by reduced T-cell representation (34.19% vs 44.54%, P = 0.029). Within the B-cell compartment, GC B cell populations were expanded in AH, particularly Cycling B cells (15.07% vs 2.86%, P = 0.029), whereas memory B cells were reduced (21.48% vs 32.18%, P = 0.029). B-cell receptor analysis demonstrated reduced somatic hypermutation frequencies across multiple mature B-cell subsets in AH, accompanied by an isotype distribution skewed towards IgM with reduced class-switched fractions. Although CD8⁺ tissue-resident memory T-cell (TRM) frequencies were similar between groups, CD8⁺ TRM in AH adenoids displayed interferon-polarised and antigen-processing signatures, and T-cell clonal expansion occurred predominantly within this subset.

These findings suggest that AH is not merely an anatomic cause of upper airway obstruction but also an immunologically active mucosal state associated with ongoing immune remodelling and antiviral defence.