Dental therapy in children with PID

Primary Immunodeficiencies (PID) arise from rare genetic defects affecting humoral and cellular immunity, which can lead to reduced dental plaque control. This study aimed to characterize the subgingival dental plaque microbiome in neutropenic PID children compared to healthy controls and assess their response to non-surgical periodontal therapy. Subgingival plaque was collected from 3 first molars and 1 first incisor at baseline and 6 months post-therapy from children with PID (n=24) and systematically healthy control participants (n=25). The subgingival microbiome was profiled using an Illumina metabarcoding approach on the bacterial 16S rRNA gene V1-V2 region. Significant shifts in community structure were observed post-therapy, measured by alpha and beta diversities. Increase in Rothia spp., Neisseria spp., and Actinomyces spp. was noted in PID children post-therapy, consistent with clinical improvements. Baseline blood absolute neutrophil counts in PID children were positively associated with Streptococcus cristatus and Gemella spp., and negatively with Saccharibacteria, Capnocytophaga, and Porphyromonas spp., highlighting key host-microbial relationships. Non-surgical periodontal therapy ameliorated dysbiosis in neutropenic PID children, revealing novel host-microbial interactions important for oral microbiome in health.