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Thesis
Profiling the nasal microbiome in people with multiple sclerosis
University of Iowa
Master of Science (MS), University of Iowa
Spring 2026
Abstract
Multiple sclerosis (MS) is a neurodegenerative autoimmune disease affecting 2.9 million people globally. During MS, the myelin sheath surrounding axons in the central nervous system (CNS) is damaged, creating lesions in the brain and spinal cord which cause a range of symptoms including long-term disability. MS is the most common progressive neurological condition affecting young adults ages 20-40 in the United States. Relapsing-Remitting Multiple Sclerosis (RRMS) is characterized by recurrent periods of relapse and remission and makes up 85% of initially diagnosed cases. Although genetics accounts for some of the risk for developing MS, most of the risk is due to environmental factors including the host microbiome. The microbiome refers to the trillions of microorganisms occupying specific niches on the human body including the gut, mouth, and nose. Although the gut and oral microbiomes have been extensively studied in MS and found to have microbial dysbiosis, there is limited research on the nasal microbiome despite its close anatomical proximity to the brain via the olfactory system. Nasal microbiome dysbiosis has also been identified in other neurological conditions such as Parkinson’s disease and Alzheimer’s disease. There is increasing evidence of a potential link between the nasal microbiome and MS disease pathobiology, but this remains largely unexplored.In this study, DNA was extracted from nasal swabs collected from a cohort of 86 healthy controls (HC) and 65 RRMS patients and 16S rRNA sequencing was performed. Within-sample diversity or alpha-diversity was determined using the Chao1, Shannon index, and Faith’s phylogenetic diversity metrics. Comparisons of taxa composition between groups or beta-diversity were determined using the weighted and unweighted UniFrac indices. Comparisons between RRMS and HC groups were performed by stratifying samples based on sex, age, body mass index (BMI), treatment status, and season. Differential abundance analyses identified specific bacterial genera and species that were enriched in RRMS or HC groups. Together, these methods identified an altered state of the nasal microbiome in people with RRMS.
We observed that RRMS patients had reduced nasal microbiome richness and phylogenetic diversity. This was true even when our cohort was stratified by sex, age, or treatment status. RRMS patients who were female, ≥40 years of age, or receiving treatment at the time of sample collection had reduced alpha-diversity compared to HC in the same stratified category. In the case of BMI stratified cohorts, only phylogenetic diversity was decreased in overweight RRMS patients. Our study found that the presence of rare taxa contributed to the distinct clustering of HC and RRMS group bacterial composition. However, distinct bacterial communities in our beta diversity analyses were not identified when cohorts were stratified by any other variable. Distinct bacterial genera were identified between nasal HC and RRMS patients including enriched Veillonella in HC and Staphylococcus in RRMS. Distinct bacterial species identified included enriched Staphylococcus caprae and Staphylococcus epidermidis in RRMS patients and enriched Streptococcus sanguinis, Haemophilus parainfluenzae, and Neisseria mucosa in HC. To our knowledge, this study is the first to identify seasonal changes in the nasal microbiome of RRMS patients, including reduced alpha-diversity (richness and phylogenetic diversity) in the summer and spring as well as bacterial composition differences during the fall. In corroboration with our previous findings, a greater number of distinct bacterial genera and species between HC and RRMS groups were identified during the summer, spring, and fall compared to winter.
This study indicates that the nasal microbiome in people with RRMS is distinct, suggesting a potential role of the nasal microbiome in RRMS pathogenesis. Specifically, we identified altered states of decreased diversity and the enrichment of specific bacterial taxa that significantly differed between RRMS patients and HC. These findings offer a better understanding of the interplay between MS and the nasal microbiome, supporting its potential importance as an environmental factor in MS pathogenesis. Profiling the differences of the nasal microbiome in RRMS compared to a healthy state provides potential avenues for early disease detection and diagnostic biomarkers for MS. Our study provides compelling evidence for studying lesser-known microbiomes to elucidate the multifactorial nature of neurodegenerative conditions such as MS.
Details
- Title: Subtitle
- Profiling the nasal microbiome in people with multiple sclerosis
- Creators
- Aracely Miron-Ocampo
- Contributors
- Ashutosh K Mangalam (Advisor)Alexander W Boyden (Committee Member)Dustin Bosch (Committee Member)
- Resource Type
- Thesis
- Degree Awarded
- Master of Science (MS), University of Iowa
- Degree in
- Pathology
- Date degree season
- Spring 2026
- Publisher
- University of Iowa
- Number of pages
- xvi, 90 pages
- Copyright
- Copyright 2026 Aracely Miron-Ocampo
- Language
- English
- Date submitted
- 04/28/2026
- Description illustrations
- color illustrations
- Description bibliographic
- Includes bibliographical references (page 78-90).
- Public Abstract (ETD)
Multiple sclerosis (MS) affects 2.9 million people globally and is the most common neurological condition affecting young adults ages 20-40 in the United States. In MS, the host immune system begins to recognize the myelin sheath as foreign (a break in self-tolerance), resulting in inflammation and subsequent demyelination, leading to impaired signal conduction and eventual axonal loss. This process creates lesions in the brain and spinal cord that cause a range of symptoms, including long-term disability. The most common form of MS is called Relapsing-Remitting Multiple Sclerosis (RRMS) and is characterized by recurrent periods of active disease and partial or complete recovery. Genetics is known to play a role in the risk for developing MS, however, most of the risk comes from a combination of environmental factors, including the microbiome.
The microbiome is the collection of bacteria, viruses, fungi, archaea, and parasites that reside in and on the body. Studying the gut and oral microbiomes in the context of MS has revealed states of microbial imbalance or dysbiosis in MS patients. Little is known about the connection between MS and other microbiomes, such as that of the nose, despite the nose-brain connection through the olfactory system. States of microbial imbalance or dysbiosis have been found in the noses of individuals with other neurological conditions such as Parkinson’s and Alzheimer’s disease. The goal of our study was to make comparisons between RRMS and healthy nasal microbiomes known as healthy controls (HC) to identify differences or patterns that could shed light on our understanding of MS.
To accomplish our goal, nasal swabs from HC individuals and RRMS patients were used to identify the bacterial taxa that were present. The bacteria that made up each individual sample as well as comparisons between HC and RRMS patients were determined. RRMS patients, and HC were also stratified based on sex, age, body mass index (BMI), treatment status, or season. Together, these methods helped identify key differences in the nasal microbiome of people with RRMS.
We observed that RRMS patients had fewer types of bacteria and lower overall diversity compared to HC. This was true even after individuals were grouped based on sex, age, or whether they were receiving treatment. Our study found that the bacterial communities in RRMS were different from those in HC. Specific bacteria were also found to be enriched or depleted in RRMS patients compared to the nasal microbiomes of people without MS. Additionally, to our knowledge, our study is the first to identify nasal microbiome changes in RRMS patients with each changing season. The differences between RRMS patients’ nasal microbiome and those of HC were found to be more pronounced during the summer, spring, and fall.
This study found that the nasal microbiome of people with RRMS is different than that of HC, including decreased diversity and specific bacteria that were enriched or depleted in the RRMS group. These findings are the first step towards a better understanding of the connection between MS and the nasal microbiome. Identifying these differences in the nasal microbiome could lead to the development of prevention strategies and earlier disease detection for MS.
- Academic Unit
- Pathology
- Record Identifier
- 9985177074402771
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