Eosinophilic granulomatosis with polyangiitis

Eosinophilic granulomatosis with polyangiitis consists of three stages, but not all patients develop all three stages or progress from one stage to the next in the same order;[7] whereas some patients may develop severe or life-threatening complications such as gastrointestinal involvement and heart disease, some patients are only mildly affected, e.g. with skin lesions and nasal polyps.[8] EGPA is consequently considered a highly variable condition in terms of its presentation and its course.[7][8]

Diagnostic markers include eosinophil granulocytes and granulomas in affected tissue, and antineutrophil cytoplasmic antibodies (ANCA) against neutrophil granulocytes. Two pathological subsets of EGPA are differentiated by the presence of antineutrophil cytoplasmic antibodies (ANCA), autoantibodies that mistakenly target and attack specific proteins found within the cytoplasm of neutrophils.[18] The ANCA+ subtype is characterized by predominantly vasculitis-like manifestations, while the ANCA- subtype is more commonly associated with eosinophilic-related symptoms.[18] Approximately 30-40% of EGPA cases are ANCA+.[18] While the pathogenic mechanisms are not fully understood, this finding suggests a role of B cells – the precursors of ANCA-producing plasma cells – in the pathogenesis of EGPA.

The American College of Rheumatology 1990 criteria for diagnosis of Churg–Strauss syndrome lists these criteria:

• Asthma
• Eosinophilia, i.e. eosinophil blood count greater than 500/microliter, or hypereosinophilia, i.e. eosinophil blood count greater than 1,500/microliter
• Presence of mononeuropathy or polyneuropathy
• Unfixed pulmonary infiltrates
• Presence of paranasal sinus abnormalities
• Histological evidence of extravascular eosinophils

For classification purposes, a patient shall be said to have EGPA if at least four of these six criteria are positive. The presence of any four or more of the six criteria yields a sensitivity of 85% and a specificity of 99.7%.[2]

Treatment for eosinophilic granulomatosis with polyangiitis includes glucocorticoids (such as prednisolone) and other immunosuppressive drugs (such as azathioprine and cyclophosphamide). In many cases, the disease can be put into a type of chemical remission through drug therapy, but the disease is chronic and lifelong.

A systematic review conducted in 2007 indicated all patients should be treated with high-dose steroids, but in patients with a five-factor score of one or higher, cyclophosphamide pulse therapy should be commenced, with 12 pulses leading to fewer relapses than six. Remission can be maintained with a less toxic drug, such as azathioprine or methotrexate.[22]

On 12 December 2017, the FDA approved mepolizumab, the first drug therapy specifically indicated for the treatment of eosinophilic granulomatosis with polyangiitis.[23] Patients taking mepolizumab experienced a "significant improvement" in their symptoms.[23] Mepolizumab is a monoclonal antibody that targets interleukin-5, a major factor in eosinophil survival.[24]

In addition to mepolizumab, a number of emerging targeted biotherapies—including the anti-IgE monoclonal antibody omalizumab, immunomodulation with Interferon-α, and B cell therapy with rituximab—may lead to increasingly personalized treatment regimens for future EGPA patients. A review of EGPA treatments conducted in 2020 proposes integrating targeted biotherapies into EGPA management plans following failure of treatment with corticosteroids.[25]

Eosinophilic granulomatosis with polyangiitis was first described by pathologists Jacob Churg (1910–2005) and Lotte Strauss (1913–1985) at Mount Sinai Hospital in New York City in 1951, using the term "allergic granulomatosis" to describe it.[3][26] They reported "fever...hypereosinophilia, symptoms of cardiac failure, renal damage, and peripheral neuropathy, resulting from vascular embarrassment in various systems of organs"[27] in a series of 13 patients with necrotizing vasculitis previously diagnosed as "periarteritis nodosa", accompanied by hypereosinophilia and severe asthma.[28] Churg and Strauss noted three features which distinguished their patients from other patients with periarteritis nodosa but without asthma: necrotizing vasculitis, tissue eosinophilia, and extravascular granuloma.[28] As a result, they proposed that these cases were evident of a different disease entity, which they referred to as "allergic granulomatosis and angiitis".[28]

The memoir Patient, by musician Ben Watt (of Everything but the Girl fame), deals with his experience with EGPA in 1992, and his recovery.[29] Watt's case was unusual in that it mainly affected his gastrointestinal tract, leaving his lungs largely unaffected; this unusual presentation contributed to a delay in proper diagnosis. His treatment required the removal of 5 m (15 ft) of necrotized small intestine (about 75%), leaving him on a permanently restricted diet.[29]

Umaru Musa Yar'Adua, the president of Nigeria from 2007 to 2010, reportedly had EGPA and died in office of complications of the disease.[30]

DJ and author Charlie Gillett was diagnosed with EGPA in 2006; he died four years later.[31]

Japanese ski jumper Taku Takeuchi, who won the bronze medal in the team competition in 2014, has the disease and competed at the Sochi Olympics less than a month after being released from hospital treatment.[32]

New Zealand reporter and television presenter Toni Street was diagnosed with the condition in 2015.[33][34] Street has had health problems for several years, including removal of her gallbladder four months prior.[35]

American professional basketball player Willie Naulls died on 22 November 2018 in Laguna Niguel, California, from respiratory failure due to EGPA,[36] which he had been battling for eight years.[37]

Canadian stand-up comic Candy Palmater died on December 25, 2021, shortly after being diagnosed with EGPA.[38]

Filipino actress Kris Aquino, sister of former Philippine President Benigno Aquino III, revealed on 16 May 2022 that she was diagnosed with EGPA.[39]