Cluster Analysis to Explore Clinical Subphenotypes of Eosinophilic Granulomatosis With Polyangiitis

OBJECTIVE

Previous studies suggested that distinct phenotypes of eosinophilic granulomatosis with polyangiitis (EGPA; formerly known as Churg-Strauss syndrome) could be determined by the presence or absence of antineutrophil cytoplasmic antibodies (ANCA), reflecting predominant vasculitic or eosinophilic processes, respectively. This study explored whether ANCA-based clusters or other clusters can be identified in EGPA.

METHODS

This study used standardized data of 15 European centers for patients with EGPA fulfilling widely accepted classification criteria. We used multiple correspondence analysis, hierarchical cluster analysis, and a decision tree model. The main model included 10 clinical variables (musculoskeletal [MSK], mucocutaneous, ophthalmological, ENT, cardiovascular, pulmonary, gastrointestinal, renal, central, or peripheral neurological involvement); a second model also included ANCA results.

RESULTS

The analyses included 489 patients diagnosed between 1984 and 2015. ANCA were detected in 37.2% of patients, mostly perinuclear ANCA (85.4%) and/or antimyeloperoxidase (87%). Compared with ANCA-negative patients, those with ANCA had more renal (P < 0.001) and peripheral neurological involvement (P = 0.04), fewer cardiovascular signs (P < 0.001), and fewer biopsies with eosinophilic tissue infiltrates (P = 0.001). The cluster analyses generated 4 (model without ANCA) and 5 clusters (model with ANCA). Both models identified 3 identical clusters of 34, 39, and 40 patients according to the presence or absence of ENT, central nervous system, and ophthalmological involvement. Peripheral neurological and cardiovascular involvement were not predictive characteristics.

CONCLUSION

Although reinforcing the known association of ANCA status with clinical manifestations, cluster analysis does not support a complete separation of EGPA in ANCA-positive and -negative subsets. Collectively, these data indicate that EGPA should be regarded as a phenotypic spectrum rather than a dichotomous disease.

Cluster Analysis To Explore Clinical Subphenotypes Of Eosinophilic Granulomatosis With Polyangiitis (Churg-Strauss)

OBJECTIVE

Previous studies suggested that distinct phenotypes of eosinophilic granulomatosis with polyangiitis (EGPA) could be determined by presence or absence of antineutrophil cytoplasmic antibodies (ANCA), reflecting predominant vasculitic or eosinophilic processes, respectively. This study explored whether ANCA-based clusters or other clusters can be identified in EGPA.

METHODS

This study used standardized data of 15 European centers for patients with EGPA fulfilling widely accepted classification criteria. We used multiple correspondence analysis, hierarchical cluster analysis, and a decision tree model. The main model included 10 clinical variables (musculoskeletal, mucocutaneous, ophthalmological, ENT, cardiovascular, pulmonary, gastrointestinal, renal, central or peripheral neurological involvement); a second model also included ANCA results.

RESULTS

The analyses included 489 patients diagnosed in 1984-2015. ANCA were detected in 37.2% of patients, mostly P-ANCA (85.4%) and/or anti-myeloperoxidase (87.0%). Compared with ANCA-negative patients, those with ANCA had more renal (P<0.001) and peripheral neurological involvement (P=0.04), fewer cardiovascular signs (P<0.001) and fewer biopsies with eosinophilic tissue infiltrates (P=0.001). The cluster analyses generated four (model without ANCA) and five clusters (model with ANCA). Both models identified three identical clusters of 34, 39 and 40 patients according to the presence or absence of ENT, CNS and ophthalmological involvement. Peripheral neurological and cardiovascular involvement were not predictive characteristics.

CONCLUSION

Although reinforcing the known association of ANCA status with clinical manifestations, cluster analysis does not support a complete separation of EGPA in ANCA-positive and -negative subsets. Collectively, these data indicate that EGPA should be regarded as a phenotypic spectrum rather than a dichotomous disease.

Respiratory manifestations of eosinophilic granulomatosis with polyangiitis (Churg–Strauss)

The respiratory manifestations of eosinophilic granulomatosis with polyangiitis (EGPA) have not been studied in detail.

In this retrospective multicentre study, EGPA was defined by asthma, eosinophilia and at least one new onset extra-bronchopulmonary organ manifestation of disease.

The study population included 157 patients (mean±sd age 49.4±14.1 years), with a mean±sd blood eosinophil count of 7.4±6.4×109 L−1 at diagnosis. There was a mean±sd of 11.8±18.2 years from the onset of asthma to the diagnosis of EGPA, of 1.4±8.4 years from the first onset of peripheral eosinophilia to the diagnosis of EGPA, and of 7.4±6.4 years from EGPA diagnosis to the final visit. Despite inhaled and oral corticosteroid treatment, the severity of asthma increased 3–6 months before the onset of the systemic manifestations. Asthma was severe in 57%, 48%, and 56% of patients at diagnosis, at 3 years, and at the final visit, respectively. Persistent airflow obstruction was present in 38%, 30%, and 46% at diagnosis, at 3 years, and at the final visit, respectively.

In EGPA, asthma is severe, antedates systemic manifestations by a mean of 12 years, and progresses to long-term persistent airflow obstruction despite corticosteroids in a large proportion of patients, which affects long-term management and morbidity.

Eosinophilic granulomatosis with polyangiitis (Churg-Strauss) (EGPA) Consensus Task Force recommendations for evaluation and management

OBJECTIVE

To develop disease-specific recommendations for the diagnosis and management of eosinophilic granulomatosis with polyangiitis (Churg-Strauss syndrome) (EGPA).

METHODS

The EGPA Consensus Task Force experts comprised 8 pulmonologists, 6 internists, 4 rheumatologists, 3 nephrologists, 1 pathologist and 1 allergist from 5 European countries and the USA. Using a modified Delphi process, a list of 40 questions was elaborated by 2 members and sent to all participants prior to the meeting. Concurrently, an extensive literature search was undertaken with publications assigned with a level of evidence according to accepted criteria. Drafts of the recommendations were circulated for review to all members until final consensus was reached.

RESULTS

Twenty-two recommendations concerning the diagnosis, initial evaluation, treatment and monitoring of EGPA patients were established. The relevant published information on EGPA, antineutrophil-cytoplasm antibody-associated vasculitides, hypereosinophilic syndromes and eosinophilic asthma supporting these recommendations was also reviewed.

DISCUSSION

These recommendations aim to give physicians tools for effective and individual management of EGPA patients, and to provide guidance for further targeted research.

Can HLA-DRB4 Help to Identify Asthmatic Patients at Risk of Churg-Strauss Syndrome?

HLA-DRB4 gene is associated with Churg-Strauss syndrome (CSS), a systemic eosinophilic vasculitis with a prodromal phase characterized by severe asthma, eosinophilia, nasal polyposis, and sinusitis. Aim of this study was to evaluate if the presence of HLA-DRB4 in asthmatic patients is associated with a clinical picture resembling that of the prodromal phase of CSS. HLA-DRB1 was determined in a cohort of 159 asthmatic patients and its frequency was compared with that of 1808 blood donors. HLA-DRB4 presence/absence was correlated with clinical features, including sinusitis, nasal polyposis, eosinophils, antiasthmatic drugs, asthma severity, and pulmonary function tests. HLA-DRB4 gene was associated with severe persistent asthma before treatment (P < 0.02), near fatal or severe hypoxemic asthma (P < 0.01), sinusitis (P < 0.01), nasal polyposis (P < 0.01), number of patients with eosinophils >1000/ μ l: (P < 0.05), need of beclomethasone >1000-2000  μ g/daily (P < 0.001), use of a third controller (P < 0.05), and oral prednisone (P < 0.02). HLA-DRB4 gene is associated in asthmatic patients with a clinical picture characterized by asthma severity, sinusitis, nasal polyposis, and eosinophilia closely resembling that of the prodromal phase of CSS and might be useful to suspect corticosteroids-masked cases of CSS.

Churg-Strauss angiitis

Churg-Strauss angiitis or syndrome (CSA) is defined as an eosinophil-rich and granulomatous inflammation involving the respiratory tract, and necrotising vasculitis affecting small- to medium-sized vessels, and is associated with asthma and eosinophilia. It is usually classified among the so-called anti-neutrophil antibody (ANCA)-associated systemic vasculitides (AASVs) because of its clinical and pathological features that overlap with those of the other AASVs. However, two recent studies on large cohorts of patients have found that ANCAs, usually P-ANCAs/MPO-ANCAs, were present in only 38% of patients. Moreover, the ANCA status was shown to segregate with clinical phenotype. ANCA-positive patients were significantly more likely to have disease manifestations associated with small-vessel vasculitis, including necrotising glomerulonephritis, mononeuritis and purpura, whereas ANCA-negative cases were significantly more likely to have cardiac and lung involvement. Vasculitis was documented less frequently in histological specimens from ANCA-negative patients in comparison with ANCA-positive ones. These findings have led to postulate the predominance of distinct pathogenetic mechanisms in the two subsets of patients: an ANCA-mediated process in ANCA-positive patients and tissue infiltration by eosinophils with subsequent release of toxic product in ANCA-negative cases. Preliminary results suggest that ANCA-positive and ANCA-negative patients also might have a different genetic background. Corticosteroids remain the cornerstone of the initial treatment of CSA. The addition of cyclophosphamide is indicated in treatment of patients with poor-prognosis factors or in patients without poor-prognosis factors but those that are prone to relapses. The length of the maintenance therapy remains to be established. However, the vast majority of patients require long-term corticosteroids treatment to control asthma.

HLA-DRB4 as a genetic risk factor for Churg-Strauss syndrome

OBJECTIVE

To explore the association between HLA alleles and Churg-Strauss syndrome (CSS), and to investigate the potential influence of HLA alleles on the clinical spectrum of the disease.

METHODS

Low-resolution genotyping of HLA-A, HLA-B, and HLA-DR loci and genotyping of TNFA -238A/G and TNFA -308A/G single-nucleotide polymorphisms were performed in 48 consecutive CSS patients and 350 healthy controls.

RESULTS

The frequency of the HLA-DRB1*07 allele was higher in the CSS patients than in controls (27.1% versus 13.3%; chi(2) = 12.64, P = 0.0003, corrected P [P(corr)] = 0.0042, odds ratio [OR] 2.42, 95% confidence interval [95% CI] 1.47-3.99). The HLA-DRB4 gene, present in subjects carrying either HLA-DRB1*04, HLA-DRB1*07, or HLA-DRB1*09 alleles, was also far more frequent in patients than in controls (38.5% versus 20.1%; chi(2) = 16.46, P = 0.000058, P(corr) = 0.000232, OR 2.49, 95% CI 1.58-3.09). Conversely, the frequency of the HLA-DRB3 gene was lower in patients than in controls (35.4% versus 50.4%; chi(2) = 7.62, P = 0.0057, P(corr) = 0.0228, OR 0.54, 95% CI 0.35-0.84). CSS has 2 major clinical subsets, antineutrophil cytoplasmic antibody (ANCA)-positive, with features of small-vessel vasculitis, and ANCA-negative, in which organ damage is mainly mediated by tissue eosinophilic infiltration; analysis of HLA-DRB4 in patients categorized by different numbers of vasculitic manifestations (purpura, alveolar hemorrhage, mononeuritis multiplex, rapidly progressive glomerulonephritis, and constitutional symptoms) showed that its frequency strongly correlated with the number of vasculitis symptoms (P for trend = 0.001).

CONCLUSION

These findings indicate that HLA-DRB4 is a genetic risk factor for the development of CSS and increases the likelihood of development of vasculitic manifestations of the disease.

The common allergens in the Churg-Strauss syndrome

BACKGROUND

The asthmatic-prodromal phase of Churg-Strauss syndrome (CSS) is usually considered allergic, but data about the involved allergens are scarce. The aim of our work was to examine the prevalence of allergy in a group of CSS patients and in two control groups of persistent asthmatic subjects selected for eosinophilia >10% [first control group patients (CGP1)] and eosinophils <6% [second control group patients (CGP2)].

METHODS

The respiratory symptoms, and the results of prick test and/or RAST for the common allergens, performed before the vasculitic phase in 51 CSS, were retrospectively evaluated and compared with those of 46 CGP1 and 50 CGP2.

RESULTS

31.4% of CSS vs 67.4% of CGP1 (P = 0.0004) and vs 58.0% CGP2 (P = 0.007) were allergic. The number of subjects with seasonal allergies was lower in CSS vs CGP1 (P = 0.0069) and vs CGP2 (P = 0.0002). The number of perennial allergies was significantly higher in CSS than in both control groups (CSS vs CGP1, P = 0.0108; CSS vs CGP2, P = 0.0079). The subjects allergic to Dermatophagoides were prevalent in CSS vs CGP1 (P = 0.0045) but not vs CGP2.

CONCLUSIONS

The evidence of allergy, considered as the demonstration of specific IgE consistent with the clinical history, is present in less than one-third of CSS and the higher prevalence of seasonal allergies in the controls disagrees with persistent asthma. Allergy may be only one of several mechanisms triggering exacerbation of asthma or supporting chronic airway inflammation as in asthma in general. Alternatively, unidentified allergens may play a role.

Renal involvement in Churg-Strauss syndrome

BACKGROUND

Churg-Strauss syndrome (CSS) is a rare disorder characterized by asthma, eosinophilia, and systemic vasculitis. Renal involvement is not regarded as a prominent feature, and its prevalence and severity vary widely in published reports that usually refer to small series of selected patients.

METHODS

We examined the prevalence, clinicopathologic features, and prognosis of renal disease in 116 patients with CSS.

RESULTS

There were 48 men and 68 women with a mean age of 51.9 years (range, 18 to 86 years). Signs of renal abnormalities were present in 31 patients (26.7%). Rapidly progressive renal insufficiency was documented in 16 patients (13.8%); urinary abnormalities, 14 patients (12.1%); and chronic renal impairment, 1 patient. There were 3 additional cases of obstructive uropathy. Sixteen patients underwent renal biopsy, which showed necrotizing crescentic glomerulonephritis in 11 patients. Other diagnoses were eosinophilic interstitial nephritis, mesangial glomerulonephritis, and focal sclerosis. Antineutrophil cytoplasmic antibody (ANCA) was positive in 21 of 28 patients (75.0%) with nephropathy versus 19 of 74 patients without (25.7%; P < 0.001). In particular, all patients with necrotizing crescentic glomerulonephritis were ANCA positive. After a median follow-up of 4.5 years, 10 patients died (5 patients with nephropathy) and 7 patients developed mild chronic renal insufficiency. Five-year mortality rates were 11.7% (95% confidence interval, 3.9 to 33.3) in patients with nephropathy and 2.7% (95% confidence interval, 0.7 to 10.7) in those without (P = 0.10).

CONCLUSION

Renal abnormalities are present in about one quarter of patients with CSS. The prevailing picture is ANCA-associated necrotizing crescentic glomerulonephritis; however, other forms of nephropathy also may occur. Outcome and long-term follow-up usually are good.

Prevalence and clinical significance of antineutrophil cytoplasmic antibodies in Churg-Strauss syndrome

OBJECTIVE

Churg-Strauss syndrome (CSS) is classified among the so-called antineutrophil cytoplasmic antibody-associated systemic vasculitides (AASVs) because of its clinicopathologic features that overlap with the other AASVs. However, while antineutrophil cytoplasmic antibodies (ANCAs) are consistently found in 75-95% of patients with Wegener's granulomatosis or microscopic polyangiitis, their prevalence in CSS varies widely and their clinical significance remains uncertain. We undertook this study to examine the prevalence and antigen specificity of ANCAs in a large cohort of patients with CSS. Moreover, we evaluated the relationship between ANCA positivity and clinicopathologic features.

METHODS

Immunofluorescence and enzyme-linked immunosorbent assay were used to determine the presence or absence of ANCAs in 93 consecutive patients at the time of diagnosis. The main clinical and pathologic data, obtained by retrospective analysis, were correlated with ANCA status.

RESULTS

ANCAs were present by immunofluorescence in 35 of 93 patients (37.6%). A perinuclear ANCA (pANCA) pattern was found in 26 of 35 patients (74.3%), with specificity for myeloperoxidase (MPO) in 24 patients, while a cytoplasmic ANCA pattern, with specificity for proteinase 3, was found in 3 of 35 patients (8.6%). Atypical patterns were found in 6 of 30 patients with anti-MPO antibodies (20.0%). ANCA positivity was associated with higher prevalences of renal disease (51.4% versus 12.1%; P < 0.001) and pulmonary hemorrhage (20.0% versus 0.0%; P = 0.001) and, to a lesser extent, with other organ system manifestations (purpura and mononeuritis multiplex), but with lower frequencies of lung disease (34.3% versus 60.3%; P = 0.019) and heart disease (5.7% versus 22.4%; P = 0.042).

CONCLUSION

ANCAs are present in approximately 40% of patients with CSS. A pANCA pattern with specificity for MPO is found in most ANCA-positive patients. ANCA positivity is mainly associated with glomerular and alveolar capillaritis.

[Churg-Strauss syndrome: is it a rare disease?]

We describe four patients with Churg-Strauss syndrome admitted to the hospital in 1988. Some clinical and histological features of particular relief are present in these cases. All patients had been treated with corticosteroids and they are now in remission. Our work suggests that Churg-Strauss syndrome is not a rare disease and that an early diagnosis and appropriate therapy may influence favourably at least long term survival.