Granulomatosis with polyangiitis (GPA) is an autoimmune disease which is a type of anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis that frequently affects the lungs and kidneys. However, GPA limited to a single organ has also been reported. A 73-year-old man was admitted for back pain and fever. We detected elevated levels of inflammatory markers and myeloperoxidase-ANCA. Magnetic resonance imaging indicated diffuse inflammation of the back and psoas muscles. Histology showed degenerated muscle fibers and granulomatosis vasculitis with mixed lymphoplasma cell infiltration. High-dose methylprednisolone therapy improved his symptoms. A final diagnosis of GPA limited to the muscles was made.

The role of biomarkers in the diagnosis of inflammatory bowel disease is not fully characterized. C-reactive protein has a short half-life and elevates quickly after the onset of an inflammatory process, the performance is better in Crohn’s disease than in ulcerative colitis. Erythrocyte sedimentation rate is easy to determine, widely available, and cheap but the long half-life the influence of age, anemia, smoking, and drugs limit its usefulness. Fecal markers have good specificity, but suboptimal accuracy. Microbial antibodies and novel immunological markers show promise but need further evidence before entering clinical practice. Proteomic methods could represent the dawn of a new era of stool protein/peptide biomarker panels able to select patients at risk of inflammatory bowel disease.

The traditional nomenclature system for classifying Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitides (AAV), based on clinical phenotype, described Granulomatosis with Polyangiitis (GPA), Eosinophilic Granulomatosis with Polyangiitis (EGPA) and Microscopic Polyangiitis (MPA) as distinct clinical entities. This classification has proved its expedience in clinical trials and every day clinical practice, yet, a substantial overlap in clinical presentation still exists, and often causes difficulties in prompt definition and clinical distinction. Additionally, new insights into the AAV pathogenesis point out that PR3 and MPO-AAV may not represent expressions of the same disease spectrum but rather two distinct disorders, as they display significant differences. Thus, it is supported that a classification based on ANCA serotype (PR3-ANCA, MPO-ANCA or ANCA-negative), could be more accurate and also closer to the nature of the disease, instead of the phenotype-based one. This review aims to elucidate the major differences between PR3 and MPO-AAV, in terms of epidemiology, pathogenesis, histological and clinical manifestations, and response to therapeutic approaches.

Autoimmune kidney diseases arise from a loss of tolerance to antigens, often with unclear triggers. In this review we explore the role of the gut microbiome and how disease, diet and therapy can alter the gut microbiota consortium. Perturbations in the gut microbiota may induce the translocation of microbiota-derived inflammatory molecules such as liposaccharide (LPS) and other toxins systemically by penetrating the gut epithelial barrier. Once in the blood stream these pro-inflammatory mediators activate immune cells which release pro-inflammatory molecules many of which are antigens in autoimmune diseases. The ratio of gut bacteria Bacteroidetes:Firmicutes is associated with worse outcomes in multiple autoimmune kidney diseases including Lupus nephritis, MPO-ANCA vasculitis and Goodpasture’s syndrome. Therapies which enhance short chain fatty acid (SCFA)-producing bacteria in the gut have powerful therapeutic potential. Dietary fibre is fermented by gut bacteria which in turn release SCFAs which protect the gut barrier as well as modulate immune responses towards a tolerogenic anti-inflammatory state. Herein, we describe where the current field of research is and the strategies to harness the gut microbiome as potential therapy.

Eosinophilic Granulomatosis with Polyangiitis (EGPA) is a rare systemic necrotizing vasculitis, affecting small-to-medium sized vessels. EGPA’s clinical manifestations are heterogeneous affecting different organs and systems and the upper respiratory tract can be affected with Ear, Nose and Throat (ENT) involvement. The aim of our study was to assess type manifestations at time of diagnosis in a cohort of EGPA patients and correlate findings with baseline variables (sex, age, antineutrophil cytoplasmic antibodies –ANCA- status) and literature reports. Main ENT manifestations in our patients at time of diagnosis were: nasal polyposis (CRSwNP) (52%), turbinate hypertrophy (48%), nasal swelling (40%), rhinorrhoea (40%), chronic rhinosinusitis without nasal polyposis (CRSsNP) (32%), nasal bone deformities (32%), nasal crusts (20%), nasal mucosal ulcers (12%), corditis (12%), hoarseness/dysphonia (12%), hearing loss (12%), mucoceles(4%) eosinophilic rhinitis (4%). No correlations were found between sex, age, ANCA status and ENT clinical manifestations. A polymorphic ENT involvement is often observed at early stages of EGPA. The presence of nasal, sinus, ear and/or laryngeal manifestations in patients with asthma and hypereosinophilia, independently of sex, age or ANCA status, should raise allert for further investigation and differential diagnosis for EGPA. ENT specialists should be aware of their leading position in this diagnostic race.