Microscopic polyangiitis: Advances in diagnostic and therapeutic approaches

Area of Science:

• Immunology
• Rheumatology
• Pathology

Background:

• Microscopic polyangiitis (MPA) is an idiopathic autoimmune disease causing systemic vasculitis, primarily affecting small blood vessels.
• It is strongly associated with antineutrophil cytoplasmic autoantibodies (ANCA), particularly those targeting myeloperoxidase (MPO).
• MPA is part of the ANCA-associated vasculitides, impacting multiple organs, predominantly the kidneys and lungs.

Purpose of the Study:

• To summarize the understanding of microscopic polyangiitis (MPA), including its characteristics, diagnosis, and treatment.
• To highlight the role of ANCA in the pathogenesis of MPA.
• To discuss the current therapeutic strategies and their impact on patient prognosis.

Main Methods:

• Diagnosis relies on clinical presentation, imaging (CT), ANCA testing, and biopsy of affected organs (kidneys, lungs).
• Treatment involves aggressive immunosuppression, typically with cyclophosphamide and corticosteroids.
• Evaluation of alternative therapies like rituximab for non-responsive cases.

Main Results:

• MPA affects small-calibre blood vessels and can lead to multi-organ involvement, with kidneys and lungs being most commonly affected.
• While not considered primary symptoms, Ear, Nose, and Throat (ENT) manifestations are frequently observed.
• Aggressive immunosuppressive therapy has significantly improved the prognosis, with high remission rates.

Conclusions:

• MPA is a serious autoimmune condition requiring prompt diagnosis and treatment.
• Standard immunosuppressive regimens achieve remission in the majority of patients.
• Rituximab offers a viable alternative for patients with inadequate response to conventional therapies.