Natural Killer Cells in Anti-Neutrophil Cytoplasmic Antibody-Associated Vasculitis - A Review of the Literature

Anti-neutrophil cytoplasmic antibody (ANCA)- associated vasculitis (AAV) is a group of systemic autoimmune diseases characterized by inflammation of small- and medium-sized vessels. The three main types of AAV are granulomatosis with polyangiitis (GPA), microscopic polyangiitis (MPA) and eosinophilic granulomatosis with polyangiitis (EGPA). A growing number of studies focus on natural killer (NK) cells in AAV. NK cells are innate lymphoid cells with important roles in anti-viral and anti-tumor defense, but their roles in the pathogenesis of autoimmunity is less well established. In this review, we will present a summary of what is known about the number, phenotype and function of NK cells in patients with AAV. We review the literature on NK cells in the circulation of AAV patients, studies on tissue resident NK cells and how the treatment affects NK cells.

Avacopan, a Selective C5a Receptor Antagonist, for Anti-Neutrophil Cytoplasmic Antibody-Associated Vasculitis

Avacopan, an orally administered C5a receptor (C5aR) antagonist, has been approved for the treatment of microscopic polyangiitis (MPA) and granulomatosis with polyangiitis (GPA) in Japan and the United States. In ADVOCATE Phase III clinical trial, patients with active MPA or GPA received either 30 mg avacopan twice daily or prednisone on a tapering schedule in combination with rituximab or cyclophosphamide (followed by azathioprine). The trial met its two primary endpoints: avacopan showed non-inferiority to prednisone for achieving remission at week 26 (avacopan, 72.3%; prednisone, 70.1%; p < 0.001 for non-inferiority and p = 0.24 for superiority) and superiority for maintaining remission at week 52 (65.7% for avacopan, 54.9% prednisone, p < 0.001 for non-inferiority and p = 0.007 for superiority). Of several key secondary endpoints tested, the glucocorticoid toxicity index (GTI)-cumulative worsening score and GTI-aggregate improvement score were significantly lower in the avacopan group than in the prednisone group at both weeks 26 and 52. Serious adverse events related and unrelated to the worsening vasculitis were reported at 10.2% and 37.3% in the avacopan group and at 14.0% and 39.0% in the prednisone group, respectively. Avacopan has set the stage for the semi-glucocorticoid-free or glucocorticoid-free treatment of MPA and GPA.

Review of guideline for the management of ANCA-associated vasculitis, presented in 2021 by the American College of Rheumatology/Vasculitis Foundation

The anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitides (AAVs) are a group of severe life-threatening autoimmune diseases, and one of the most important problems in practical rheumatology. This article discusses 2021 American College of Rheumatology/Vasculitis Foundation guideline for the management of AAVs, including granulomatosis with polyangiitis (GPA), microscopic polyangiitis (MPA), and eosinophilic granulomatosis with polyangiitis (EGPA). The guideline features 26 recommendations and 5 upgraded position statements for GPA/ MPA, as well as 15 recommendations and 5 upgraded position statements for EGPA, which became the basis for the proposed algorithms for the treatment of patients with GPA/MPA and EGPA. Particular attention has been paid to the use of biologics.

Posterior Reversible Encephalopathy Syndrome in a Patient With Microscopic Polyangiitis: A Case Report and Literature Review

Central nervous system (CNS) is rarely involved in microscopic polyangiitis (MPA). Here, we report a 14-year-old girl with MPA who developed new-onset seizures with deterioration of renal function. Her brain CT scan and MRI showed concurrent complications of intracerebral hemorrhage and posterior reversible encephalopathy syndrome (PRES). She got remission with combinations of methylprednisolone pulse, plasma exchange, regular hemodialysis, antiseizure and antihypertension medications. Furthermore, it is crucial to exclude the adverse effect of medications such as corticosteroid and biological therapy. We searched the literatures, retrieved 6 cases of MPA with PRES and summarized their clinical characteristics.

CLINICAL CASE: MICROSCOPIC POLYANGIITIS AS ONE OF THE MAIN VARIANTS OF PULMONARY-RENAL SYNDROME

Клинические проявления микроскопического полиангиита многообразны, что затрудняет своевременную диагностику и соответственно адекватное лечение. Цель: привлечь внимание терапевтов, пульмонологов, нефрологов к своевременному выявлению легочно-почечного синдрома и установлению его нозологической основы, в частности микроскопического полиангиита на примере клинического случая. Материалы и методы: проведены обследование пациента с микроскопическим полиангиитом и дифференциальная диагностика в рамках легочно-почечного синдрома. Результаты: на основании анамнеза заболевания, результатов клинического и дополнительных методов исследования пациента, установлен диагноз микроскопического полиангиита. Выводы: для ранней диагностики микроскопического полиангиита необходима настороженность при возникновении легочно-почечного синдрома в виде сочетания гломерулонефрита и геморрагического альвеолита на фоне сосудистой пурпуры. Clinical manifestations of microscopic polyangiitis are diverse, which complicates timely diagnosis and, accordingly, adequate treatment. Goal: to draw the attention of therapists, pulmonologists, nephrologists to the timely detection of pulmonary-renal syndrome and the establishment of its nosological basis, in particular microscopic polyangiitis by the example of a clinical case. Materials and methods: an examination of a patient with microscopic polyangiitis and differential diagnosis within the framework of pulmonary-renal syndrome were carried out. Results: based on the anamnesis of the disease, the results of clinical and additional research methods of the patient, the diagnosis of microscopic polyangiitis was established. Conclusions: for early diagnosis of microscopic polyangiitis, alertness is necessary in the event of pulmonary-renal syndrome in the form of a combination of glomerulonephritis and hemorrhagic alveolitis against the background of vascular purpura.