Two subtypes of Churg–Strauss syndrome with neuropathy: the roles of eosinophils and ANCA

Anti-neutrophil Cytoplasmic Antibody-negative Eosinophilic Granulomatosis with Polyangiitis Complicated with Peripheral Neuropathy that Underwent Remission Induction with Mepolizumab Monotherapy

A 72-year-old woman was admitted to our hospital with numbness in her lower extremities and hypereosinophilia. She was diagnosed with eosinophilic granulomatosis with polyangiitis (EGPA). On admission, she was suspected of being complicated with pneumonia and sepsis; therefore, treatment with mepolizumab monotherapy was begun, resulting in partial improvement. After the possibility of a complicating infection was ruled out, corticosteroids were initiated, followed by intravenous gamma globulin therapy. Although the induction of remission of EGPA with mepolizumab monotherapy is not usually recommended, induction with mepolizumab monotherapy may be an option in terms of safety and clinical efficacy in some cases.

Distinct features of hypereosinophilic syndrome with neuropathy from eosinophilic granulomatosis with polyangiitis

BACKGROUND AND OBJECTIVES

Hypereosinophilic syndrome (HES) and eosinophilic granulomatosis with polyangiitis (EGPA) have overlapping clinical considerations, which frequently involve peripheral neuropathy. The current study aimed to discriminate between the clinicopathological features of HES and EGPA, focusing on the mechanism of peripheral nerve damage.

METHODS

A total of 53 patients who underwent nerve biopsies at our laboratory were examined: nine patients with idiopathic HES (iHES), three patients with reactive HES, 14 patients with myeloperoxidase-anti-neutrophil cytoplasmic antibody (ANCA)-positive EGPA, and 27 patients with negative EGPA. Nerve biopsies were performed using light and electron microscopy.

RESULTS

Polyneuropathy was more common than mononeuritis multiplex in iHES, which differed from that in ANCA-negative EGPA groups (p = 0.012). Nerve biopsies showed that iHES was associated with neuropathy features such as rare vasculitis and non-vasculitic eosinophilic infiltrates, which differed from those of ANCA-negative EGPA. Fibrinoid necrosis was found only in the reactive HES and ANCA-positive groups. The percentage of endoneurial vessels occluded with eosinophils tended to be higher in iHES (1.8%) than in ANCA-positive EGPA (0%) and negative EGPA (0.7%). In a patient with ANCA-negative EGPA, the endoneurial vessels were occluded with platelets, fibrinoid materials, and eosinophils, demonstrating the morphology of eosinophil extracellular traps.

CONCLUSION

iHES with neuropathy showed a pattern more similar to polyneuropathy than mononeuritis multiplex, which is dominant in ANCA-negative EGPA, and tended to show vasculitis in the peripheral nerves less frequently compared with EGPA. Eosinophilic infiltration and endoneurial vascular occlusion by eosinophils may cause nerve damage.

At the Heart of Eosinophilic Granulomatosis with Polyangiitis: into Cardiac and Vascular Involvement

PURPOSE OF REVIEW

To provide an overview of existing literature on pathogenetic and clinical aspects of cardiac and vascular involvement in eosinophilic granulomatosis with polyangiitis (EGPA).

RECENT FINDINGS

In EGPA, cardiac and vascular involvement are more common than previously thought. However, no international recommendations on the topic are available yet. Herein, we summarize the existing evidence on the topic and propose a diagnostic approach for cardiac involvement in EGPA. The prevalence of cardiovascular involvement in patients with EGPA varies greatly among published studies, ranging between 3.1-18.7% for occlusive arterial disease, 5.8-30% for venous thrombosis and 17-92% for heart involvement. Cardiac involvement in EGPA is associated with high mortality even though manifestations are heterogeneous. In principle, every anatomical structure of the heart can be involved, and EGPA-related heart disease may be completely asymptomatic at first. A careful diagnostic work-up for early detection and prompt treatment initiation is therefore required. While cardiac manifestations are more common in anti-neutrophil cytoplasmic antibodies (ANCA)-negative patients, arterial and venous thrombotic events are not linked to ANCA status but correlate closely with disease activity and accumulate at disease onset. Thrombotic events (mainly venous) are considerably more frequent in EGPA than in the general population contributing substantially to morbidity and highlighting the importance of developing specific prevention strategies for patients who are diagnosed with EGPA.

Long-term Safety and Efficacy of Benralizumab for Eosinophilic Granulomatosis with Polyangiitis Complicated with Severe Neuropathy

The efficacy of benralizumab, as well as mepolizumab, to granulomatosis with polyangiitis (EGPA) involved with mononeuritis multiplex remains unclear. We experienced a case of EGPA presenting neuropathy with severe asthma. Muscle weakness due to neuropathy involved with gait disturbance was partly ameliorated by intravenous immunoglobulin therapy. Mepolizumab (100 mg/day) did not promote further improvement of neuropathy. However, the administration of benralizumab instead of mepolizumab improved neuropathy quickly and enabled walking alone. The efficacy of benralizumab for EGPA and its complication has been maintained for over four years. Benralizumab may be a possible treatment for EGPA presenting neuropathy with severe asthma.

[Neuropathy presenting conduction block in ANCA-negative eosinophilic granulomatosis with polyangiitis]

A 74-year-old woman with a history of asthma and allergic rhinitis rapidly developed multiple mononeuropathy. Although anti-neutrophil cytoplasmic antibodies were negative, the presence of eosinophilia and eosinophilic infiltrations in the sural nerve led to a diagnosis of eosinophilic granulomatosis with polyangiitis. A motor nerve conduction study on admission revealed conduction block, which promptly disappeared after initiating immunotherapy without findings suggestive for remyelination or axonal degeneration. This electrophysiological change distinct from that of Wallerian degeneration. A biopsy of the sural nerve showed many eosinophil infiltrations and degranulation of eosinophilic cationic protein within nerve fascicles, whereas findings of necrotizing vasculitis were absent. These findings suggest that a direct effect of eosinophilic cationic protein, rather than ischemic damage due to vasculitis, was the main mechanism of transient nerve conduction failure in this patient.

[Eosinophilic granulomatosis with polyangiitis presenting with Guillain-Barré syndrome-like acute course. A case report]

A 57-years-old man with a history of bronchial asthma and pansinusitis developed acute progressive muscle weakness and sensory disturbance of the distal limbs after upper respiratory infection. On day 15 after onset of sensory disturbance and muscle weakness, the patient admitted to our hospital. A neurological examination revealed asymmetry weakness of both proximal and distal muscles, "glove and stocking type" hypoesthesia, and paresthesia without obvious pain. Blood tests and a nerve conduction study demonstrated eosinophilia and elevation of MPO-ANCA, axonal multiple mononeuropathy, respectively. The cerebrospinal fluid was normal. Eosinophilic granulomatosis with polyangiitis (EGPA) or Guillain-Barré syndrome (GBS) were suspected. So intravenous immunoglobulin therapy (IVIg) and high dose methylprednisolone pulse therapy (HDMP) followed by oral prednisolone were started. However, neurological symptoms did not improve. Sural nerve biopsy on day 31 revealed varying myelinating fiber loss at every nerve bundle and perivascular lymphocytic infiltration. The results did not fulfill the pathologic criteria for EGPA, but supported the changes of vasculitis. Cyclophosphamide (CPA) pulse therapy was administered for the additional therapy. Neurological symptoms did not improve and worsened again after decreasing oral prednisolone; therefore, combined therapy with IVIg, HDMP, and CPA was administered. Neurological symptoms then diminished gradually and the MPO-ANCA level and number of eosinophils normalized. This case suggests the importance of early nerve biopsy to obtain pathological findings supportive of EGPA diagnosis to allow introduction of aggressive immunosuppressive therapy such as CPA in a case with acute progressive motor-sensory neuropathy due to EGPA mimicking GBS.

Low-dose mepolizumab is effective as an add-on therapy for treating long-lasting peripheral neuropathy in patients with eosinophilic granulomatosis with polyangiitis

OBJECTIVE

To assess the effectiveness of low-dose mepolizumab as an add-on therapy for treating peripheral neurological symptoms in eosinophilic granulomatosis with polyangiitis (EGPA).

METHODS

We prospectively studied 13 EGPA patients with conventional treatment-resistant peripheral neuropathy. Their symptoms (pain, numbness, and muscle weakness) were assessed on a visual analogue scale (VAS) before and after 12 months of mepolizumab therapy (100 mg every 4 weeks). Peripheral eosinophil levels and several biomarkers including urinary levels of eosinophil-derived neurotoxin (EDN) were measured before and after therapy.

RESULTS

VAS scores for pain and numbness significantly improved after 12 months of mepolizumab therapy (from 67.0 to 48.0, P = 0.012, and from 67.0 to 51.0, P = 0.017, respectively). However, the VAS score for muscle weakness did not improve (P = 0.36). There were significant correlations between treatment-related changes in urinary EDN levels from baseline to 6 months later and percent changes in the VAS scores of pain and numbness (r = 0.75, P = 0.020; r = 0.88, P = 0.002).

CONCLUSIONS

Treatment-resistant peripheral neuropathy in EGPA was significantly improved by low-dose mepolizumab, and effectiveness was correlated with decreased urinary EDN. Because the possibility of a placebo effect cannot be formally excluded, placebo-controlled studies will be required in the future.

Eosinophilic Granulomatosis With Polyangiitis: Dissecting the Pathophysiology

Eosinophilic Granulomatosis with Polyangiitis (EGPA) is a rare multisystemic disease classified both amongst hypereosinophilic disorders and ANCA-associated vasculitis. Vessel inflammation and eosinophilic proliferation are the hallmarks of the disease and main effectors of organ damage. Two distinct disease phenotypes have classically been described according to ANCA-status: the ANCA-negative subset with eosinophil-driven manifestation and the ANCA-positive one with vasculitic manifestations. An analogous dichotomization has also been backed by histological findings and a distinct genetic background. EGPA is typically consider a Th2-mediated disease and blood and tissue eosinophilia represent the cornerstone of diagnosis. Besides, ANCA are known for inducing endothelial injury and vascular inflammation by activating the circulating neutrophils. Thus, the pathogenesis of EGPA seems to be mediated by two coexisting mechanisms. However, the verbatim application of this strict dualism cannot always be translated into routine clinical practice. In the present review we describe the current knowledge on the eosinophilic and ANCA-mediated aspects of EGPA pathogenesis. Finally, we review the rationale of the currently proposed EGPA dichotomy and future research perspectives.

Eosinophilic granulomatosis with polyangiitis: the multifaceted spectrum of clinical manifestations at different stages of the disease

Introduction: Eosinophilic granulomatosis with polyangiitis (EGPA) usually occurs in patients with late-onset asthma and sustained peripheral blood eosinophilia and classically presents with a clinical multifaceted spectrum of manifestations, which may vary at the different stages of the natural history of the disease.Areas covered: We reviewed EGPA clinical presentation, focusing on clinical manifestations at three different phases of the disease: 1/before the development of overt vasculitis, 2/at vasculitis diagnosis and 3/during the long-term follow-up. An update on current classification criteria and recent therapeutic advances has been provided as well.Expert opinion: Asthma, chronic rhinosinusitis and blood eosinophilia could anticipate the overt vasculitis for years. An atopic background may be present in a subset of patients (25-30%), while ANCA presence varies between 10 and 40%. Systemic vasculitis rapidly occurs and clinical features demonstrating vasculitis processes (neuropathy, purpura, scleritis, alveolar hemorrhage and glomerulonephritis) develop along with systemic symptoms (50%). After vasculitis resolution, asthma remains severe in up to 50% of patients and incidence of isolated-asthma and rhinosinus exacerbations remains constantly high. Different sets of classification criteria have been published so far, and DCVAS diagnostic criteria will be presented soon. Interleukin-5 blockers seem to be promising to control the disease and to spare corticosteroids.

Overall Disability Sum Score for Clinical Assessment of Neurological Involvement in Eosinophilic Granulomatosis With Polyangiitis

AIM

The aim of this study was to verify the application of Overall Disability Sum Score (ODSS) for standardized clinical assessment of neurological involvement in patients with eosinophilic granulomatosis with polyangiitis (EGPA) and its correlation with treatment response and long-term outcomes.

METHODS

Consecutive EGPA patients referred to our tertiary vasculitis center were retrospectively evaluated. Patients' neurological damage and disability were systematically assessed with Vasculitis Damage Index and ODSS.

RESULTS

Fifty EGPA patients were included in the study with a median follow-up of 75 months (9-180 months). Twenty-five (50%) developed peripheral neuropathy, 17 (68%) presented mononeuritis multiplex, whereas 8 (32%) had symmetric polyneuropathy. Patients with neurological involvement were older (56.3 ± 13.4 vs. 44.4 ± 12.1 years, P < 0.0009), more frequently antineutrophil cytoplasmic antibody positive (48% vs. 16%, P = 0.015), and were more likely to have renal involvement (24% vs. 0%, P = 0.022). An early clinical response to therapy was observed within 6 months of treatment, resulting in a significant decrease in ODSS, which fell from the baseline value of 4.2 ± 2.4 to 2.9 ± 1.5 (P = 0.0001), whereas only a slow decreasing pattern was noted over the long-term period. However, all subjects developed neurological impairment and disability despite remission from active vasculitis. Patients with ODSS of greater than 3 at baseline (n = 13 [52%]) retained a higher score at the last examination (P < 0.001), predicting a low therapeutic response. Furthermore, ODSS of greater than 3 was found associated with more neurological relapses (53.8% vs. 0%, P = 0.027).

CONCLUSION

Overall Disability Sum Score could be a rapid, simple, reliable instrument to evaluate the severity of disability and nerve damage due to neurological involvement caused by vasculitis and to predict, at presentation, improvement and risk of neurological worsening.

Superior turbinate eosinophilia correlates with olfactory deficit in chronic rhinosinusitis patients

OBJECTIVE

To evaluate if molecular markers of eosinophilia in olfactory-enriched mucosa are associated with olfactory dysfunction.

STUDY DESIGN

Cross-sectional study of tissue biopsies from 99 patients, and an additional 30 patients who underwent prospective olfactory testing prior to sinonasal procedures.

METHODS

Tissue biopsies were processed for analysis of inflammatory markers using quantitative real time polymerase chain reaction (qRT-PCR). Ipsilateral olfactory performance was assessed using the Sniffin' Sticks (Burghart, Wedel, Germany) threshold component and the University of Pennsylvania Smell Identification Test (Sensonics, Haddon Heights, NJ). Age-adjusted data was correlated with inflammatory marker expression and clinical measures of obstruction from computed tomography and endoscopy.

RESULTS

Gene expression of the eosinophil marker CLC (Charcot Leyden crystal protein) was elevated in superior turbinate (ST) tissue in chronic rhinosinusitis (CRS) with nasal polyps (CRSwNP) compared to ST and inferior turbinate tissue in CRS without nasal polyps (CRSsNP) and control patients (all P < 0.001, respectively). CLC in ST tissue was correlated with IL-5 and eotaxin-1 expression (all P < 0.001; P = 0.65, and 0.49, respectively). CLC expression was strongly correlated with eosinophilic cationic protein levels (P < 0.001; r = -0.76), and ST CLC expression was inversely related to olfactory threshold (P = 0.002, r = -0.57) and discrimination scores (P = 0.05, r = -0.42). In multiple linear regression of CLC gene expression, polyp status, and radiographic and endoscopic findings with olfactory threshold, CLC was the only significantly correlated variable (P < 0.05).

CONCLUSION

Markers of eosinophils are elevated in the ST of patients with CRSwNP and correlate with olfactory loss. These findings support the hypothesis that olfactory dysfunction in CRS correlates local eosinophil influx into the olfactory cleft.

LEVEL OF EVIDENCE

NA. Laryngoscope, 127:2210-2218, 2017.

Neutrophil extracellular traps in neuropathy with anti-neutrophil cytoplasmic autoantibody-associated microscopic polyangiitis

To clarify the roles of neutrophils in anti-neutrophil cytoplasmic autoantibody (ANCA)-associated vasculitic neuropathy, we studied neutrophil extracellular traps (NETs) in peripheral nerve vasculitis. Stored nerve samples from 17 patients with microscopic polyangiitis (MPA) were immunohistochemically analyzed using antibodies for citrullinated histone H3 (citH3) and various neutrophil enzymes. We defined merged citH3 and extracellularly released myeloperoxidase (MPO) as NET formation. We also compared NET formation between MPO-ANCA-positive/negative MPA and rheumatoid arthritis (RA)-associated vasculitic neuropathy. NETs were identified mostly in vasculitic small arterioles of 6 of 12 MPO-ANCA-positive MPA patients, and their frequency was higher (p < 0.05) than in ANCA-negative patients. NETs were not found in vasculitic neuropathy with RA or patients with chronic inflammatory demyelinating polyradiculoneuropathy. NETs were also observed in the peripheral nervous system of MPA patients as well as in the lung and kidney. These results suggest that NETs may be involved in the pathogenesis of MPA neuropathy.

Clinical Characteristics and Treatment Response of Peripheral Neuropathy in the Presence of Eosinophilic Granulomatosis with Polyangiitis (Churg-Strauss Syndrome): Experience at a Single Tertiary Center

Background and Purpose

Eosinophilic granulomatosis with polyangiitis (EGPA) is a rare systemic small-vessel vasculitis accompanied by asthma, eosinophilia, and eosinophilic inflammation of various tissues including the peripheral nerves. This study investigated the clinical course and long-term outcomes of peripheral neuropathy in patients with EGPA.

Methods

Seventy-one patients with physician-diagnosed EGPA were identified at Samsung Medical Center between January 1995 and April 2014. Sixty-one of these patients were followed-up for more than 1 year and received corticosteroid therapy with or without intravenous cyclophosphamide pulse therapy for 6 to 18 months. Medical records of the 61 patients including demographic data, clinical features, laboratory and pathological findings, treatments, and outcomes were reviewed.

Results

Peripheral neuropathy as a manifestation of EGPA was present in 46 (75%) of the 61 patients. The mean follow-up duration of the patients with neuropathy was 6.4 years (range 1.2–18.8 years). The scores on the neurological functional disability scale before and after the combination treatment with corticosteroid and cyclophosphamide were 2.43±0.86 and 0.54±0.95 (mean±SD; p<0.001), respectively. The peripheral neuropathy relapsed in one patient.

Conclusions

The long-term clinical outcome of peripheral neuropathy in patients with EGPA receiving initial corticosteroid and cyclophosphamide combination therapy was favorable with a very low relapse rate.

Churg-Strauss Syndrome: an evolving paradigm

The Churg-Strauss Syndrome is an ANCA-associated vasculitis, an inflammatory multisystem disease with preference to the respiratory tract. Peripheral and tissue eosinophilia are the pathological hallmarks of this condition. The etiopathogenesis is unknown but some cytokines appear to play a central role and could be targets for new therapies.