Elevated Myeloperoxidase-antineutrophil Cytoplasmic Antibody Research Articles

Microscopic polyangiitis presented with biopsy-confirmed pleuritis.

We describe a case of microscopic polyangiitis manifested as pleuritis confirmed by thoracoscopic biopsy. An 80-year-old man presented with a three-day history of shortness of breath and cough. Chest radiography revealed patchy opacities in the lower fields of the bilateral lung and right-sided pleural effusion. Thoracentesis revealed lymphocytic pleural exudates. Thoracoscopic biopsy specimens were compatible with fibrotic pleuritis. He developed rapidly progressive glomerulonephritis with elevated myeloperoxidase anti-neutrophil cytoplasmic antibody titer in blood and pleural effusion. Although the patient was resistant to two weekly courses of pulse steroid therapy, he was successfully treated with a five-day course of intravenous immunoglobulin.

Chronically Elevated Myeloperoxidase Antineutrophil Cytoplasmic Antibody Levels in an Asymptomatic 91-year-old Patient

Myeloperoxidase antineutrophil cytoplasmic antibody (MPO-ANCA) associated glomerulonephritis is commonly diagnosed in elderly patients with acute kidney injury (AKI). Prompt diagnosis and rapid initiation of appropriate therapy are essential to avoid the development of ANCA-associated vasculitis, which can be a life- and organ-threatening disease. We report a rare case of a 91-year-old male with a high MPO-ANCA titer, who took allopurinol, and showed no symptoms for >20 months, following which sudden AKI and severe bronchial asthma necessitated hemodialysis and steroid administration. Chronically elevated ANCA titers should be examined for causes and followed up to limit the risk of subsequent disease development.

Successful treatment of refractory aortitis in antineutrophil cytoplasmic antibody-associated vasculitis using tocilizumab

A 47-year-old Japanese woman developed antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) complicated by a rare combination of aortitis and hypertrophic pachymeningitis. Despite the therapy with prednisolone and cyclophosphamide, the aortitis was not ameliorated. However, after cyclophosphamide was replaced with intravenous tocilizumab, the aortitis was improved, and the prednisolone dose was successfully tapered to 4 mg/day without elevation in C-reactive protein and myeloperoxidase ANCA (MPO-ANCA) levels. Several studies have reported that tocilizumab is effective for aortitis associated with Takayasu's arteritis and giant cell arteritis. On the other hand, we succeeded to improve the aortitis in AAV with monthly administration of tocilizumab. Moreover, we successfully controlled disease activity and enabled the tapering of prednisolone to 4 mg/day without relapses of AAV symptoms and elevated MPO-ANCA levels. It indicates that tocilizumab may be therapeutically beneficial for not only aortitis but also AAV itself. In conclusion, tocilizumab was effective in treating glucocorticoid- and cyclophosphamide-resistant AAV-associated aortitis. This is the first report demonstrating the successful treatment of AAV-associated aortitis using tocilizumab.

Hypertrophic pachymeningitis with MPO-ANCA-positive vasculitis

A 75-year-old man presented with headache, right facial palsy, and left hemiparesis. Because of elevated myeloperoxidase-antineutrophil cytoplasmic antibody (MPO-ANCA) titers and findings from magnetic resonance imaging (MRI) which were compatible with hypertrophic pachymeningitis (HP), he was diagnosed with MPO-ANCA-positive HP. He was treated with the combination therapy of steroid and cyclophosphamide (CY), leading to good prognosis. We present a case of HP associated with MPO-ANCA-positive vasculitis and emphasize the importance of MPO-ANCA tests as a predictable factor for relapse of the disease in order to start earlier treatment for the disease.

Neonatal microscopic polyangiitis secondary to transfer of maternal myeloperoxidase–antineutrophil cytoplasmic antibody resulting in neonatal pulmonary hemorrhage and renal involvement

Microscopic polyangiitis is a systemic vasculitis characterized by small vessel involvement. Studies suggest myeloperoxidase-antineutrophil cytoplasmic antibody (MPO-ANCA) is involved in its pathogenesis, and the titer may reflect disease activity. To report a case of transplacental transfer of MPO-ANCA from a mother to a 33-week gestational age neonate that resulted in neonatal pulmonary hemorrhage and renal involvement that was successfully treated with high-dose steroid therapy and exchange transfusion. MPO-ANCA titers from the cord blood and the neonate on the 8th, 15th, and 25th days of life (DOLs) were obtained. Metabolic panels and chest x-ray examinations were performed for the neonate and mother and the following values were measured: ANCA, erythrocyte sedimentation rate, C-reactive protein, antinuclear antibody, serial urinalysis, and complete blood cell count. Anti-glomerular basement membrane, quantitative immunoglobulins, anticardiolipin antibody, and rheumatoid factor were also measured for the neonate. The neonate had elevated MPO-ANCA titers at birth. Pulmonary hemorrhage and renal involvement were seen on DOL 2. High-dose steroid therapy decreased symptoms within 1.5 hours of initiation. Exchange transfusion performed on DOL 5 removed all of the remaining MPO-ANCA by DOL 25. The child remains asymptomatic to date. To our knowledge, this is the first reported case of transplacental transfer of MPO-ANCA resulting in pulmonary-renal syndrome that was successfully treated with high-dose steroid therapy and exchange transfusion.