The role of gutmicrobiota composition, epigenetics and autoimmunity in the development and treatment of vasculitis; the VASKIR biobank

Relevance: In the Netherlands, 100-300/100.000 people have some form of
autoimmune systemic vasculitis which includes all types of vasculitis as
defined by the Chapel Hill classification (1). Large-vessel vasculitides (LVV)
include giant cell arteritis (GCA) and Takayasu arteriitis. Small-vessel
vasculitides (SVV) are mainly associated with anti-neutrophil cytoplasmic
antibodies (ANCA) and include granulomatosis with polyangiitis (GPA),
microscopic polyangiitis (MPA) and eosinophilic GPA (EGPA). Other types
affecting different vessel sizes (also termed variable vessel vasculitis) are
Behçet*s disease, IgA vasculitis (formerly known as Henoch-Schönlein purpura),
polyarteriitis nodosa (PAN), vasculitis associated with systemic lupus
erythematosus (SLE) and vasculitis due to systemic sclerosis. Despite a clear
improvement in outcome over the last decades and upcoming novel therapeutics
(2), vasculitis is associated with considerable morbidity and mortality (3, 4).
Improved survival coincides with an increased risk of side-effects from
intensive long-term immunosuppression, resulting in a high incidence of
infections. Better and structured follow-up of vasculitis patients is needed,
to better categorize them on the road to patient tailored medical therapy.

Background: Autoimmunity is the hallmark of LVV and SVV, and this process may
originate from an immune response to gut microbiota. Indeed, the composition of
gut microbiota was found to be altered in several studies including different
types of vasculitis (5), but diagnostic and predictive values remain to be
established. Nevertheless, molecular mimicry and microbiota driven antibodies
are thought to play a role in vasculitis (6, 7). Activation of innate immunity
by intestinal microbes may be critical for accelerating vasculitis by expanding
both T-helper 1 (Th1) and T-helper 17 (Th17) cells in the small intestine
(8-10). Another mechanism linking the microbiome to immunological tone are
microbial metabolites (11) and subsequent epigenetic modification (12). While
most microbiome research focused on bacteria, gut viruses (virome) and fungi
(all present in fecal samples) are also implicated in development of vasculitis
because of consequent T-cell activation and exhaustion (13). These parameters
are influenced by the different types of treatment used (14).
Capillary microscopy is a standard noninvasive diagnostic tool for systemic
sclerosis, with similar sensitivity and specificity as the ANA titer. Data on
capillary architecture in other vasculitides is scarce, and it is unknown
whether there is any diagnostic or prognostic value. The current study offers
an opportunity to investigate this further. Thus the association between the
gut microbiome/virome, T-cell exhaustion and immuno-tolerance in autoimmune
vasculitis constitutes an important knowledge gap withholding a therapeutic
target that will be addressed in this prospective cohort study.

Primary Objective: Primary: Gut microbiota (oral and fecal) and nasal
microbiota composition in relation to autoimmunity status (antibodies (ANA,
ANCA) and HLA subtype) and inflammatory functional assays as well as disease
activity parameters in patients with autoimmune vasculitis

Secondary Objective:
Gut microbiota (oral and fecal) and nasal microbiota composition in relation to:
• Questionnaires about abdominal complaints (to rule out intercurrent
gastrointestinal infections), quality of life
• Efficacy of medication in relation to microbiota changes as well as on
circulating immune cell panel (including T-cells, B-cells, neutrophils and
monocytes measured by flow cytometry and functional assays) and plasma
metabolites
• HLA type by high resolution sequencing of circulating neutrophils
• DNA buffycoat (whole genome sequencing and epigenetics)

This will be a cross-sectional observational cohort study. This study is
performed in the outpatient setting. Individuals with vasculitis >18 years old
will be invited to participate and included if eligible and willing to
participate. A cross-sectional design is sufficient to establish whether
individuals with vasculitis carry a distinct microbiome and whether these
individuals have altered circulating immune-cell and/or (epi)genetic signature.
Moreover, we aim to study whether changes in gut and nasal microbiota
composition and plasma metabolite profiles are associated with outcome and
treatment efficacy.

This is an observational study without invasive measurements outside of a test
for which patients will be fasted. We will therefore record the following
adverse events in the CRF if they occur:
• Hematoma after venous puncture, larger than 6cm
• Syncope


The CRU will monitor this study, and this study has been reported to the CRU
(please see attached form).