D105-13 Familial Airway Microbiome Signatures in Primary Ciliary Dyskinesia: Insights From 16S-rRNA Gene Sequencing

Rationale Primary Ciliary Dyskinesia (PCD) is a rare genetic lung disorder caused by pathogenic variants in approximately 54 genes. Recent studies have shown that heterozygous parents of individuals with PCD exhibit increased airway inflammation, as demonstrated by single-cell RNA sequencing. However, it remains unclear whether this inflammatory response is driven by heterozygosity itself or by shared environmental factors. To begin addressing this question, we investigated whether family members of individuals with PCD—who share similar environmental exposures—exhibit comparable airway microbiome profiles. Methods Experiments were approved by the IRB at Washington University and all participants provided assent or consent. Patients with well-characterized and genetically defined PCD, and their families were recruited. Individuals with recent PCD exacerbations, recent exposure to antibiotics or systemic steroids were excluded. Phenotypic characteristics including age, gender, respiratory and non-respiratory symptoms, and environmental exposures were recorded for the participants. Nasal swab samples were collected using the DNA/RNA ShieldTM Lysis Tubes (Microbe) w/Collection Swab (R1104), (Zymo Research, Irvine, CA). DNA and RNA were purified and extracted in parallel per ZymoBIOMICSTM DNA/RNA Miniprep Kit protocol (R2002), (Zymo Research, Irvine, CA). The 16s rRNA sequencing was performed in the Genome Technology Access Center (GTAC) at Washington University in St. Louis. Results Sixty-nine (69) participants, from twenty-one (21) families were recruited in the study. Ten (10) families were recruited from the PCD and Rare lung disease center at WashU Medicine/Saint Louis Children’s Hospital (SLCH), Saint Louis, Missouri, USA and eleven (11) families were recruited from Amish community at Buffalo, Missouri, USA. The study group included thirty-three (33) individuals with a genetically confirmed PCD diagnosis and thirty-six (36) family members, including parents and siblings, whenever possible. Participants underwent upper airway sampling for 16S rRNA analysis. 16S rRNA gene sequencing revealed that PCD airways are highly colonized with different microbiota genera. Interestingly, there were clustering by age as observed in previous studies. In a model looking at family associated with the clusters; family was barely statistically significant (P = 0.04995). Conclusions PCD airways are highly colonized with different microbiota. Individuals with PCD did not have a typical age dependent taxa distribution. There is high concordance between individuals with PCD and their families suggesting high transmission rates between members. Future prospectives will include comparing the airway microbiome of PCD families to control families, including cystic fibrosis, asthma and healthy families using shotgun metagenomics. Shotgun metagenomics will allow for enhanced detection of bacterial species and increased detection of diversity.