Faculty Bibliography

OBJECTIVE: Reactive arthritis (ReA) is an inflammatory disorder occurring several weeks after gastrointestinal or genitourinary infections. HLA-B27 positivity is considered a risk factor, though not necessarily predictive of disease incidence. Among non-genetic factors, the intestinal microbiome may play a role in disease susceptibility. The objective of this study was to characterize the gut microbiota and host gene interactions in ReA and post-infectious spondyloarthritis. METHODS: Adult peripheral spondyloarthritis and control subjects with preceding infections that did not develop arthritis were prospectively recruited from a highly prevalent geographic region. Clinical variables, HLA status, and 16S rRNA gene sequencing of intestinal microbiota were analyzed. RESULTS: ReA subjects showed no significant differences from controls in gut bacterial richness or diversity. However, there was a significantly higher abundance of Erwinia and Pseudomonas, and increased prevalence of typical enteropathogens associated with ReA. Subjects with ultrasound evidence of enthesitis were enriched in Campylobacter, while subjects with uveitis and radiographic sacroiliitis were respectively enriched in Erwinia and unclassified Ruminococcaceae, and both enriched in Dialister. Host genetics, particularly HLA-A24, were associated with differences in gut microbiota diversity irrespective of disease status. We determined several co-occurring taxa that were also predictive of HLA-A24 status. CONCLUSION: This is the first culture-independent study characterizing the gut microbial community of post-infectious arthritis. Although bacterial factors correlated with disease presence and clinical features of ReA, host genetics also appeared to be a major independent driver of intestinal community composition. Understanding of these gut microbiota host-genetic relationships may further clarify the pathogenesis of post-infectious spondyloarthropathies.

PURPOSE: Reflux esophagitis (ReE) and eosinophilic esophagitis (EoE) are associated with the presence of eosinophils in esophageal mucosa and are considered to be important co-morbid factors for chronic cough and asthma in adults. We hypothesize that esophageal eosinophils related to ReE and EoE are present in children with refractory asthma and chronic cough and correlate with airway eosinophilia. METHODS: We performed a retrospective analysis of medical records of children who underwent "triple endoscopy" (sleep laryngoscopy, bronchoscopy with bronchoalveolar lavage (BAL) and endobronchial biopsy (EBB), and esophagogastroduodenoscopy with esophageal biopsy (EsB)) at our Aerodigestive Center for evaluation of refractory asthma and cough. Inclusion criteriawere cough for 8 weeks or more with no response to trial of antibiotics and systemic/inhaled corticosteroids (ICS), poor control of asthma symptoms, and/or airflowlimitations and air trapping despite use ICS or ICS/long-acting beta-agonist combination. Children with known cystic fibrosis, primary ciliary dyskinesia and aspiration into airway were excluded. RESULTS: Thirty-two children (22 males) met inclusion criteria. Nineteen had refractory asthma and 13 had chronic cough. There were no significant complications recorded after procedures including EBB. Eosinophils (>1%) were present in BAL of 8 (25%) children. EBB showed eosinophils in 17 (53%) children. There were a total of 19 children with eosinophils isolated from the airway (either BAL or EBB), 4 (21%) had them in BAL alone, 8 (42%) in EBB only, and 7 (37%) in both BAL and EBB. EoE was diagnosed in 6 children (19%) and ReE in 13 (41%). EsB revealed esophageal eosinophils in 47% of children. Presence of eosinophils in EsB was related to presence of eosinophils in EBB chi² (1, N = 32), p = 0.026, but not BAL (p=0.89). CONCLUSIONS: ReE and EoE with esophageal eosinophils was present in 47% of children with refractory asthma and chronic cough. There is a significant relationship between airway and esophageal eosinophils, which becomes evident only when EBB is performed for detection of airway eosinophils. Further research is required for understanding the association of airway and esophageal eosinophilia in the development and management of refractory asthma and cough