ANCA Vasculitis and Hemophagocytic Lymphohistiocytosis following a Fecal Microbiota Transplant

Macrophage Activation Syndrome in the Setting of Rheumatic Diseases

Patients with established rheumatic disorders may develop complications of macrophage activation syndrome due to severe flares of the underlying disease (adult-onset Still's disease, SLE); however, in most other rheumatic disorders, MAS develops in association with identified viral or other infectious triggers. It is therefore important to pursue appropriate studies to identify potential infectious triggers in rheumatic disease patients who develop MAS. Management is best directed toward treatment of the triggering infections and combinations of high-dose corticosteroids, calcineurin inhibitors, and biologic therapies targeting IL-1 and/or IL-6 to suppress the associated cytokine storm.

Hemophagocytic Lymphohistiocytosis and Anti-neutrophil Cytoplasmic Antibody-associated Vasculitis Possibly Caused by Enterococcus faecalis Infective Endocarditis

Infection can induce hemophagocytic lymphohistiocytosis (HLH) and anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV). We herein report a 52-year-old man who had HLH and AAV simultaneously, possibly caused by Enterococcus faecalis infective endocarditis. The HLH diagnosis was based on the HLH-2004 criteria. AAV was diagnosed based on a positive result for proteinase-3 ANCA and necrotizing vasculitis of the small vessels on a skin biopsy. He eventually died and was sent for autopsy after combination treatment of valve replacement, antibiotics, and immunosuppressants, including corticosteroids. This case involved a challenging diagnosis and treatment of HLH with various complications in an adult.

An update on the microbiome in vasculitis

PURPOSE OF REVIEW

To summarize recent evidence regarding the presence and potential role of the microbiome in systemic vasculitides.

RECENT FINDINGS

Microbiomic descriptions are now available in patients with small, medium and large vessel vasculitis. The majority of studies have evaluated gastrointestinal inhabitants, with a smaller number of studies describing the nasal, pulmonary or vascular microbiomes. Most published studies are observational and cross-sectional. Dysbiosis is seen frequently in vasculitis patients with reduced microbial diversity observed in nasal, fecal and vascular samples compared with disease and/or healthy controls. Predominant bacteria vary, but overall, patients with vasculitis tend to have more pathogenic and less commensal bacteria in active disease. In the few longitudinal studies available, improvement or resolution of dysbiosis has been observed following vasculitis treatment and improved disease activity.

SUMMARY

Dysbiosis and reduced microbial diversity has been identified in patients with small, medium and large vessel vasculitis. Although limited data suggests microbiomes may 'normalize' following immunosuppression, cause or effect cannot be determined. It is hypothesized that microbial disruption in a genetically susceptible individual may trigger excessive host immune activation and vasculitis; however, larger studies with longitudinal and translational design are needed to further our current understanding.