Objectives: To evaluate changes in microbial composition and the evolution of gastrointestinal tract (GIT) symptoms in systemic sclerosis (SSc).
Methods: Adult SSc patients provided stool specimens every 3 months over the course of 1 year. Participants completed the University of California, Los Angeles (UCLA) GIT 2.0 questionnaire to assess GIT symptom severity at each stool collection. The microbiota from these samples were determined by Illumina HiSeq 2500 16S ribosomal RNA sequencing (Illumina, Inc., San Diego, California, USA). Mixed effect models evaluated changes in GIT symptoms and microbial composition over time.
Results: Among 19 patients with SSc (female; 89.5%; median age: 51.3 years), the median disease duration was 7 years and the baseline total GIT 2.0 score was 0.7 (standard deviation: 0.6). The majority of participants (63%) provided at least four stool samples over the course of the 12-month study. Patients with longer disease durations had increased GIT symptoms over the course of the study. There was no difference in the course of GIT symptoms over time between patients with limited versus diffuse cutaneous disease. The relative abundances of specific genera did not change over time within individual subjects. After controlling for age, sex, ethnicity, disease duration, and SSc subtype (i.e., limited versus diffuse), low abundance of Bacteroides was associated with increased GIT symptoms over time.
Conclusion: This study is the first to have longitudinally characterised the lower GIT microbiome in SSc patients and demonstrated relative stability of genera abundance over the course of 1 year. The findings provide additional evidence that specific genera are associated with SSc-GIT symptoms and warrant further evaluation in larger SSc studies.
An estimated 11 million workers in the USA are potentially exposed to agents that can become a cause of allergic diseases such as occupational asthma and allergic contact dermatitis, which can adversely affect health and well-being. Hundreds of chemicals (e.g. metals, epoxy and acrylic resins, rubber additives, and chemical intermediates) and proteins (e.g. natural rubber latex, plant proteins, mould, animal dander) present in virtually every industry have been identified as causes of allergic disease. In general, allergens can be classified as low molecular weight (chemical) allergens and high molecular weight (protein) allergens. These agents are capable of inducing immunological responses that are both immunoglobulin E and non-immunoglobulin E-mediated. Interestingly, the same chemical can induce diverse immune responses in different individuals. As new hazards continue to emerge, it is critical to understand the immunological mechanisms of occupational allergic disease. Specific understanding of these mechanisms has direct implications in hazard identification, hazard communication, and risk assessment. Such efforts will ultimately assist in the development of risk management strategies capable of controlling workplace exposures to allergens to prevent the induction of sensitisation in naïve individuals and inhibit elicitation of allergic responses. The purpose of this short review is to give a brief synopsis of the incidence, agents, mechanisms, and research needs related to occupational allergy.
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