Contemporary consensus proposal on criteria and classification of eosinophilic disorders and related syndromes

Hematologic Malignancies Identified in Patients with Hypereosinophilia and Hypereosinophilic Syndromes

BACKGROUND

Certain hematologic malignancies are associated with hypereosinophilia or tissue eosinophilia. It is unclear if patients with hypereosinophilia are more likely to develop one of these malignancies.

OBJECTIVE

This study sought to quantify the specific hematologic malignancies that developed in patients with preexisting hypereosinophilia.

METHODS

Adult patients with eosinophilia associated with the development of hematologic malignancy were identified by a retrospective review of the Mayo Clinic patient database between 2000 and 2013.

RESULTS

Of 2642 patients identified with eosinophilia, hypereosinophilia, or hypereosinophilic syndrome, 25 (aged 28.8 to 86.1 years; 13 male; 12 female) had a diagnosis of either lymphoma or leukemia. The majority of these patients had non-Hodgkin lymphoma (17 of 25). T-cell-derived lymphomas were more common (12 of 17) than B-cell-derived lymphomas (4 of 17). In patients with leukemia (8 of 25), chronic lymphocytic leukemia (4 of 8) was most common, followed by chronic eosinophilic leukemia (3 of 8). Approximately 5.1% of patients with hypereosinophilia developed a hematologic malignancy. On average, the malignancy developed 30.0 ± 42.7 months after the onset of hypereosinophilia.

CONCLUSIONS

The development of hematologic malignancies in this referral population with eosinophilia was rare (0.2%), but more common in those with hypereosinophilia (5.1%). Non-Hodgkin's lymphomas, particularly T-cell-derived malignancies, were most commonly diagnosed. Patients with preexisting hypereosinophilia were diagnosed with hematologic conditions that were rarer within the general population.

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.

How I treat hypereosinophilic syndromes

Hypereosinophilic syndromes (HESs) are a group of rare disorders characterized by peripheral blood eosinophilia of 1.5 × 10(9)/L or higher and evidence of end organ manifestations attributable to the eosinophilia and not otherwise explained in the clinical setting. HESs are pleomorphic in clinical presentation and can be idiopathic or associated with a variety of underlying conditions, including allergic, rheumatologic, infectious, and neoplastic disorders. Moreover, the etiology of the eosinophilia in HESs can be primary (myeloid), secondary (lymphocyte-driven), or unknown. Although corticosteroids remain the first-line therapy for most forms of HESs, the availability of an increasing number of novel therapeutic agents, including tyrosine kinase inhibitors and monoclonal antibodies, has necessarily altered the approach to treatment of HESs. This review presents an updated treatment-based approach to the classification of patients with presumed HES and discusses the roles of conventional and novel agents in the management of these patients.

CD3-CD4+ lymphoid variant of hypereosinophilic syndrome: nodal and extranodal histopathological and immunophenotypic features of a peripheral indolent clonal T-cell lymphoproliferative disorder

The CD3(-)CD4(+) lymphoid variant of hypereosinophilic syndrome is characterized by hypereosinophilia and clonal circulating CD3(-)CD4(+) T cells. Peripheral T-cell lymphoma has been described during this disease course, and we observed in our cohort of 23 patients 2 cases of angio-immunoblastic T-cell lymphoma. We focus here on histopathological (n=12 patients) and immunophenotypic (n=15) characteristics of CD3(-)CD4(+) lymphoid variant of hypereosinophilic syndrome. Atypical CD4(+) T cells lymphoid infiltrates were found in 10 of 12 CD3(-)CD4(+) L-HES patients, in lymph nodes (n=4 of 4 patients), in skin (n=9 of 9) and other extra-nodal tissues (gut, lacrymal gland, synovium). Lymph nodes displayed infiltrates limited to the interfollicular areas or even an effacement of nodal architecture, associated with proliferation of arborizing high endothelial venules and increased follicular dendritic cell meshwork. Analysis of 2 fresh skin samples confirmed the presence of CD3(-)CD4(+) T cells. Clonal T cells were detected in at least one tissue in 8 patients, including lymph nodes (n=4 of 4): the same clonal T cells were detected in blood and in at least one biopsy, with a maximum delay of 23 years between samples. In the majority of cases, circulating CD3(-)CD4(+) T cells were CD2(hi) (n=9 of 14), CD5(hi) (n=12 of 14), and CD7(-)(n=4 of 14) or CD7(low) (n=10 of 14). Angio-immunoblastic T-cell lymphoma can also present with CD3(-)CD4(+) T cells; despite other common histopathological and immunophenotypic features, CD10 expression and follicular helper T-cell markers were not detected in lymphoid variant of hypereosinophilic syndrome patients, except in both patients who developed angio-immunoblastic T-cell lymphoma, and only at T-cell lymphoma diagnosis. Taken together, persistence of tissular clonal T cells and histopathological features define CD3(-)CD4(+) lymphoid variant of hypereosinophilic syndrome as a peripheral indolent clonal T-cell lymphoproliferative disorder, which should not be confused with angio-immunoblastic T-cell lymphoma.

Antitumor activity of S116836, a novel tyrosine kinase inhibitor, against imatinib-resistant FIP1L1-PDGFRα-expressing cells

The FIP1-like-1-platelet-derived growth factor receptor alpha (FIP1L1-PDGFRα) fusion oncogene is the driver factor in a subset of patients with hypereosinophilic syndrome (HES)/chronic eosinophilic leukemia (CEL). Most FIP1L1-PDGFRα-positive patients respond well to the tyrosine kinase inhibitor (TKI) imatinib. Resistance to imatinib in HES/CEL has been described mainly due to the T674I mutation in FIP1L1-PDGFRα, which is homologous to the imatinib-resistant T315I mutation in BCR-ABL. Development of novel TKIs is imperative to overcome resistance to imatinib. We synthesized S116836, a novel TKI. In this study, we evaluated the antitumor activity of S116836 in FIP1L1-PDGFRα-expressing cells. The results showed that S116836 potently inhibited PDGFRα and its downstream signaling molecules such as STAT3, AKT, and Erk1/2. S116836 effectively inhibited the growth of the WT and T674I FIP1L1-PDGFRα-expressing neoplastic cells in vitro and in nude mouse xenografts. Moreover, S116836 induced intrinsic pathway of apoptosis as well as the death receptor pathway, coincided with up-regulation of the proapoptotic BH3-only protein Bim-EL through the Erk1/2 pathway. In conclusion, S116836 is active against WT and T674I FIP1L1-PDGFRα-expressing cells, and may be a prospective agent for the treatment of HES/CEL.

Hypereosinophilic syndrome: an indolent rash with a serious cardiac complication

Idiopathic hypereosinophilic syndrome (HES) is a rare disorder, characterized by prominent blood or tissue eosinophilia with ensuing tissue damage, which is diagnosed after exclusion of underlying diseases known to cause HES. Sustained eosinophilia is associated with cardiac disease, including endomyocardial thrombosis and fibrosis, leading to restrictive cardiomyopathy, valvular dysfunction and increased thrombotic tendency. Aneurysmal coronary artery disease (CAD) occurring in the absence of stenotic atherosclerotic plaques is extremely rare. We present a case of idiopathic HES in a 30-year-old woman with asymptomatic multianeurysmal CAD and a sinus of Valsalva aneurysm, and discuss a brief review of the literature and management strategies.

Efficacy of Dietary Treatment for Inducing Disease Remission in Eosinophilic Gastroenteritis

OBJECTIVES

Various dietary interventions have been used to treat patients with eosinophilic gastroenteritis (EGE). Concrete evidence as to the effectiveness of such treatments in inducing disease remission is, however, lacking. The aim of the study was to systematically review the efficacy of dietary therapies in inducing EGE remission.

METHODS

We performed a systematic search for the MEDLINE, EMBASE, and SCOPUS libraries for studies investigating the efficacy of dietary interventions (in both histological and symptomatic remission) for children and adults with EGE and colitis.

RESULTS

The search yielded 490 references; 30 were included in the review, with most of these references being "low-quality" individual cases or short case series. No significant publication bias was found. Elemental diets in children were linked to 75.8% of clinical improvement, but few of these patients underwent a histological evaluation. Allergy-testing results have been used scarcely in EGE. Empiric elimination of allergy-associated foods was the most commonly used option. The variable results in terms of symptom relief, however, were scarcely accompanied by histological confirmation. Clinical and methodological heterogeneity hindered the performance of quantitative summaries for the efficacy of dietary therapies in inducing disease remission.

CONCLUSIONS

Symptomatic improvements reported for dietary treatment in EGE by most of the available literature are questionable because of the lack of objective evaluation of clinical changes and the very limited assessment of histological remission. Because of the relative lack of well-designed, high-quality studies, the unequivocal use of dietary treatment for patients with EGE and colitis cannot be supported. Further research should be undertaken.

Eosinophilia in Rheumatologic/Vascular Disorders

Peripheral and tissue eosinophilia can be a prominent feature of several unique rheumatologic and vascular diseases. These diseases span a wide range of clinical features, histologic findings, therapeutic approaches, and outcomes. Despite the rare nature of these entities--which makes large-scale studies challenging--knowledge has continued to grow regarding their epidemiology, pathophysiology, and management. This review compares and contrasts 5 rheumatologic and vascular conditions in which eosinophilia can be seen: eosinophilic granulomatosis with polyangiitis (Churg-Strauss), immunoglobulin G4-related disease, diffuse fasciitis with eosinophilia, eosinophilia-myalgia syndrome, and eosinophilic myositis.

Eosinophilic Gastroenteritis: Case Report and Review in Search for Diagnostic Key Points

Eosinophilic gastroenteritis is considered an uncommon disease with a low incidence rate that remains as a diagnostic challenge for the clinician, in spite of the fact that seventy years have passed since its original description. Hereby we present the case of a 29-year-old male without history of allergies who was evaluated for unspecific gastrointestinal symptoms, without relevant findings on physical examination and presenting an initial complete blood count (CBC) with severe eosinophilia. The patient was evaluated and the diagnosis of eosinophilic gastroenteritis was confirmed by histopathological findings. The relevance of the case resides in highlighting the lack of guidelines or consensus for histological diagnosis being virtually the only one available. To a similar extent, treatment evidence is based on case series with a reasonable number of patients and case reports.

Toxicity of eosinophil MBP is repressed by intracellular crystallization and promoted by extracellular aggregation

Eosinophils are white blood cells that function in innate immunity and participate in the pathogenesis of various inflammatory and neoplastic disorders. Their secretory granules contain four cytotoxic proteins, including the eosinophil major basic protein (MBP-1). How MBP-1 toxicity is controlled within the eosinophil itself and activated upon extracellular release is unknown. Here we show how intragranular MBP-1 nanocrystals restrain toxicity, enabling its safe storage, and characterize them with an X-ray-free electron laser. Following eosinophil activation, MBP-1 toxicity is triggered by granule acidification, followed by extracellular aggregation, which mediates the damage to pathogens and host cells. Larger non-toxic amyloid plaques are also present in tissues of eosinophilic patients in a feedback mechanism that likely limits tissue damage under pathological conditions of MBP-1 oversecretion. Our results suggest that MBP-1 aggregation is important for innate immunity and immunopathology mediated by eosinophils and clarify how its polymorphic self-association pathways regulate toxicity intra- and extracellularly.

Management of hypereosinophilia in tropical settings

Hypereosinophilia includes a group of commonly encountered clinical situations with symptoms ranging from mild and clinically innocuous to devastating presentations with high morbidity and mortality. The presentations and complications can be easily missed if the clinician is unaware of the diverse entities responsible for hypereosinophilia. The hypereosinophilic syndromes encompass entities that are associated with varying degrees of organ dysfunction either directly due to eosinophilic infiltration or as a result of substances secreted by the eosinophils. These conditions may be neoplastic or reactive in aetiology and a diligent search for secondary causes is essential. Evaluation and management algorithms in the tropical setting and in developing countries may differ from elsewhere. A review of hypereosinophilia and hypereosinophilic syndromes is presented with a diagnostic and therapeutic decision making algorithm modified for use in the tropical setting.

Diagnostic challenges during pretreatment long-term follow-up in a patient with FIP1L1-PDGFRA-positive eosinophilia

Obtaining a precise characterization of eosinophilia is crucial, as successful treatment relies on the underlying etiology of the disease. Platelet-derived growth factor receptor alpha-related disorders were first specified in 2008 as a distinct group of clonal eosinophilic disorders with exceptional responsiveness to imatinib. We herein present the case of a man with myeloid neoplasm and eosinophilia in whom a definitive diagnosis could not be adequately made based on histopathological features who was ultimately diagnosed only after extensive molecular analyses and successfully treated with imatinib. In addition, we discuss the diagnostic and therapeutic approaches to treating patients presenting with eosinophilia.

Eosinophilic Pneumonia

Eosinophilic pneumonia may manifest as chronic or transient infiltrates with mild symptoms, chronic idiopathic eosinophilic pneumonia, or the frequently severe acute eosinophilic pneumonia that may be secondary to a variety of causes (drug intake, new onset of tobacco smoking, infection) and that may necessitate mechanical ventilation. When present, blood eosinophilia greater than 1 × 10⁹ eosinophils/L (and preferably greater than 1.5 × 10⁹/L) is of considerable help for suggesting the diagnosis, however it may be absent, as in the early phase of idiopathic acute eosinophilic pneumonia or when patients are already taking corticosteroids. On bronchoalveolar lavage, high eosinophilia (>25 %, and preferably >40 % of differential cell count) is considered diagnostic of eosinophilic pneumonia in a compatible setting, obviating the need of video-assisted thoracic surgical lung biopsy, which is now performed only on very rare occasions with inconsistency between clinical, biological, and imaging features. Inquiry as to drug intake must be meticulous (www.pneumotox.com) and any suspected drug should be withdrawn. Laboratory investigations for parasitic causes must take into account the travel history or residence and the epidemiology of parasites. In patients with associated extrathoracic manifestations, the diagnosis of eosinophilic granulomatosis with polyangiitis or of the hypereosinophilic syndromes should be raised. Presence of airflow obstruction can be found in hypereosinophilic asthma, allergic bronchopulmonary aspergillosis, idiopathic chronic eosinophilic pneumonia, eosinophilic granulomatosis with polyangiitis, or in the recently identified syndrome of hyperosinophilic obliterative bronchiolitis. Corticosteroids remain the cornerstone of symptomatic treatment for eosinophilic pneumonias, with a generally dramatic response. Relapses are common when tapering the doses or after stopping treatment especially in idiopathic chronic eosinophilic pneumonia. Cyclophosphamide is necessary only in patients with eosinophilic granulomatosis with polyangiitis and poor-prognostic factors. Imatinib is very effective in the treatment of the myeloproliferative variant of hypereosinophilic syndromes. Anti-interleukin-5 monoclonal antibodies are promising in the spectrum of eosinophilic disorders.

Churg-Strauss syndrome

Churg-Strauss syndrome (CSS), alternatively known as eosinophilic granulomatosis with polyangiitis (EGPA), was first described in 1951 by Churg and Strauss as a rare disease characterized by disseminated necrotizing vasculitis with extravascular granulomas occurring exclusively among patients with asthma and tissue eosinophilia. EGPA is classified as a small-vessel vasculitis associated with antineutrophil cytoplasmic antibodies (ANCAs) and the hypereosinophilic syndromes (HESs) in which vessel inflammation and eosinophilic proliferation are thought to contribute to organ damage. Although still considered an idiopathic condition, EGPA is classically considered a Th2-mediated disease. Emerging clinical observations provide compelling evidence that ANCAs are primarily and directly involved in the pathogenesis of AASVs, although recent evidence implicates B cells and the humoral response as further contributors to EGPA pathogenesis. EGPA has traditionally been described as evolving through a prodromic phase characterized by asthma and rhino-sinusitis, an eosinophilic phase marked by peripheral eosinophilia and organ involvement, and a vasculitic phase with clinical manifestations due to small-vessel vasculitis. The American College of Rheumatology defined the classification criteria to distinguish the different types of vasculitides and identified six criteria for EGPA. When four or more of these criteria are met, vasculitis can be classified as EGPA. The French Vasculitis Study Group has identified five prognostic factors that make up the so-called five-factor score (FFS). Patients without poor prognosis factors (FFS=0) have better survival rates than patients with poor prognosis factors (FFS≥1). The treatment of patients with CSS must be tailored to individual patients according to the presence of poor prognostic factors. A combination of high-dose corticosteroids and cyclophosphamide is still the gold standard for the treatment of severe cases, but the use of biological agents such as rituximab or mepolizumab seems to be a promising therapeutic alternative.

Enhanced tissue factor expression by blood eosinophils from patients with hypereosinophilia: a possible link with thrombosis

Thrombotic risk is increased in eosinophil-mediated disorders, and several hypotheses have been proposed to link eosinophilia and thrombosis. In particular, eosinophils have been described as source of tissue factor (TF), the main initiator of blood coagulation; however, this aspect is still controversial. This study was aimed to evaluate whether TF expression varies in eosinophils isolated from normal subjects and patients with different hypereosinophilic conditions. Eosinophils were immunologically purified from peripheral blood samples of 9 patients with different hypereosinophilic conditions and 9 normal subjects. Western blot analysis and real-time polymerase chain reaction (RT-PCR) were performed to test eosinophil TF expression. For comparison, TF expression was evaluated in monocytes from blood donors and in human endothelial (ECV304) and fibroblast (IMR90) cell lines. Western blot analysis revealed a major band of 47,000 corresponding to native TF in homogenates of purified eosinophils with a higher intensity in the 9 patients than in the 9 controls (p<0.0001). According to RT-PCR cycle threshold (Ct), TF gene expression was higher in eosinophils from patients than in those from controls, median (range) 35.10 (19.45-36.50) vs 37.17 (35.33-37.87) (p = 0.002), and was particularly abundant in one patient with idiopathic hypereosinophilic syndrome and ischemic heart attacks (Ct: 19.45). TF gene expression was moderate in monocytes, Ct: 31.32 (29.82-33.49) and abundant in endothelial cells, Ct: 28.70 (27.79-29.57) and fibroblasts, Ct: 22.77 (19.22-25.05). Our results indicate that human blood eosinophils contain variable amounts of TF. The higher TF expression in patients with hypereosinophilic disorders may contribute to increase the thrombotic risk.

Novel targeted therapies for eosinophil-associated diseases and allergy

Eosinophil-associated diseases often present with life-threatening manifestations and/or chronic organ damage. Currently available therapeutic options are limited to a few drugs that often have to be prescribed on a lifelong basis to keep eosinophil counts under control. In the past 10 years, treatment options and outcomes in patients with clonal eosinophilic and other eosinophilic disorders have improved substantially. Several new targeted therapies have emerged, addressing different aspects of eosinophil expansion and inflammation. In this review, we discuss available and currently tested agents as well as new strategies and drug targets relevant to both primary and secondary eosinophilic diseases, including allergic disorders.

Recurrent severe acute hepatitis caused by hypereosinophilic syndrome associated with elevated serum immunoglobulin G4 levels

A 46-year-old male was admitted to our hospital with severe acute hepatitis, hypereosinophilia, and serum immunoglobulin G4 (IgG4) elevation. Plasma exchange was performed, and he was treated by prednisolone; however, his hepatitis recurred twice over the following twelve months. Transjuglar liver biopsy was performed at the third onset, which demonstrated extensive hepatocyte necrosis, congestion, and severe eosinophil infiltration. We diagnosed hypereosinophilic syndrome (HES)-related hepatitis. Although no cholangitis was detected by imaging and pathological diagnosis, IgG4-positive cells were detected in the liver and bone marrow. Furthermore, the elevation of serum IgG4 levels was associated with the eosinophil count and his clinical condition. After the addition of azathioprine to his treatment regimen, no reoccurrence was observed. IgG4-positive cells may have contributed to the severity and refractoriness of this recurrent acute HES-related hepatitis.

The lymphoid variant of hypereosinophilic syndrome: study of 21 patients with CD3-CD4+ aberrant T-cell phenotype

The CD3-CD4+ aberrant T-cell phenotype is the most described in the lymphoid variant of hypereosinophilic syndrome (L-HES), a rare form of HES. Only a few cases have been reported, and data for these patients are scarce. To describe characteristics and outcome of CD3-CD4+ L-HES patients, we conducted a national multicentric retrospective study in the French Eosinophil Network. All patients who met the recent criteria of hypereosinophilia (HE) or HES and who had a persistent CD3-CD4+ T-cell subset on blood T-cell phenotyping were included. Clinical and laboratory data were retrospectively collected by chart review. CD3-CD4+ L-HES was diagnosed in 21 patients (13 females, median age 42 years [range, 5-75 yr]). Half (48%) had a history of atopic manifestations. Clinical manifestations were dermatologic (81%), superficial adenopathy (62%), rheumatologic (29%), gastrointestinal (24%), pulmonary (19%), neurologic (10%), and cardiovascular (5%). The median absolute CD3-CD4+ T-cell count was 0.35 G/L (range, 0.01-28.3), with a clonal TCRγδ rearrangement in 76% of patients. The mean follow-up duration after HES diagnosis was 6.9 ± 5.1 years. All patients treated with oral corticosteroids (CS) (n = 18) obtained remission, but 16 required CS-sparing treatments. One patient had a T-cell lymphoma 8 years after diagnosis, and 3 deaths occurred during follow-up.In conclusion, clinical manifestations related to CD3-CD4+ T cell-associated L-HES are not limited to skin, and can involve all tissue or organs affected in other types of HE. Contrary to FIP1L1-PDGFRA chronic eosinophilic leukemia patients, CS are always effective in these patients, but CS-sparing treatments are frequently needed. The occurrence of T-cell lymphoma, although rare in our cohort, remains a major concern during follow-up.

Histologic eosinophilic gastritis is a systemic disorder associated with blood and extragastric eosinophilia, TH2 immunity, and a unique gastric transcriptome

BACKGROUND

The definition of eosinophilic gastritis (EG) is currently limited to histologic EG based on the tissue eosinophil count.

OBJECTIVE

We aimed to provide additional fundamental information about the molecular, histopathologic, and clinical characteristics of EG.

METHODS

Genome-wide transcript profiles and histologic features of gastric biopsy specimens, as well as blood eosinophil counts, were analyzed in patients with EG and control subjects (n = 15 each).

RESULTS

The peak gastric antrum eosinophil count was 283 ± 164 eosinophils/×400 high-power field in patients with EG and 11 ± 9 eosinophils/×400 high-power field in control subjects (P = 6.1 × 10(-7)). Patients with EG (87%) had coexisting eosinophilic inflammation in multiple gastrointestinal segments; the esophagus represented the most common secondary site. Increased peripheral blood eosinophil counts (patients with EG: 1.09 ± 0.88 × 10(3)/μL vs control subjects: 0.09 ± 0.08 10(3)/μL, P = .0027) positively correlated with peak gastric eosinophil counts (Pearson r(2) = .8102, P < .0001). MIB-1(+) (proliferating), CD117(+) (mast cells), and FOXP3(+) (regulatory T cells, activated T cells, or both) cell counts were increased in patients with EG. Transcript profiling revealed changes in 8% of the genome in gastric tissue from patients with EG. Only 7% of this EG transcriptome overlapped with the eosinophilic esophagitis transcriptome. Significantly increased IL4, IL5, IL13, IL17, CCL26, and mast cell-specific transcripts and decreased IL33 transcripts were observed.

CONCLUSION

EG is a systemic disorder involving profound blood and gastrointestinal tract eosinophilia, TH2 immunity, and a conserved gastric transcriptome markedly distinct from the eosinophilic esophagitis transcriptome. The data herein define germane cellular and molecular pathways of EG and provide a basis for improving diagnosis and treatment.

Eosinophilic granulomatosis with polyangiitis (Churg-Strauss): evolutions in classification, etiopathogenesis, assessment and management

PURPOSE OF REVIEW

Eosinophilic granulomatosis with polyangiitis (EGPA) (Churg-Strauss syndrome) is a peculiar hybrid condition of a systemic antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis and a hypereosinophilic disorder with frequent lung involvement that occurs in people with asthma. This review focuses on areas of evidence or persistent uncertainty in the classification, epidemiology, clinical presentation, diagnosis, prognosis and management of EGPA and attempts to identify clues to the mechanisms in the development or course of the disease.

RECENT FINDINGS

The 2013 revision of the EGPA definition formally placed the disease in the subset of ANCA-associated vasculitides. Recently published large case series underlined that the presence of ANCAs, found in 30-40% of EGPA, determines distinct but partly overlapping disease expression and the major detrimental effect of heart involvement on survival. There is some evidence that asthma in EGPA resembles a nonallergic eosinophilic asthma phenotype. Encouraging results have been reported for the treatment of EGPA with rituximab or with the eosinophil-targeted antiinterleukin-5 agent mepolizumab.

SUMMARY

The understanding of EGPA continues to advance, but many gaps in knowledge remain. The nomenclature remains a source of conceptual variance in terms of demonstrated presence or not of vessel inflammation or ANCAs in the diagnosis of EGPA. Distinguishing EGPA from hypereosinophilic syndromes can be problematic, and an understanding of the mechanistic relation between the vasculitis and the eosinophilic proliferation is profoundly lacking. Some evidence suggests distinct disease phenotypes, but this concept has not yet been translated to phenotype-adapted therapy.

Expression profiling of differentiating eosinophils in bone marrow cultures predicts functional links between microRNAs and their target mRNAs

BACKGROUND

MicroRNAs (miRNAs) are small non-coding RNAs that regulate complex transcriptional networks underpin immune responses. However, little is known about the specific miRNA networks that control differentiation of specific leukocyte subsets. In this study, we profiled miRNA expression during differentiation of eosinophils from bone marrow (BM) progenitors (bmEos), and correlated expression with potential mRNA targets involved in crucial regulatory functions. Profiling was performed on whole BM cultures to document the dynamic changes in miRNA expression in the BM microenvironment over the differentiation period. miRNA for network analysis were identified in BM cultures enriched in differentiating eosinophils, and chosen for their potential ability to target mRNA of factors that are known to play critical roles in eosinophil differentiation pathways or cell identify.

METHODOLOGY/PRINCIPAL FINDINGS

We identified 68 miRNAs with expression patterns that were up- or down- regulated 5-fold or more during bmEos differentiation. By employing TargetScan and MeSH databases, we identified 348 transcripts involved in 30 canonical pathways as potentially regulated by these miRNAs. Furthermore, by applying miRanda and Ingenuity Pathways Analysis (IPA), we identified 13 specific miRNAs that are temporally associated with the expression of IL-5Rα and CCR3 and 14 miRNAs associated with the transcription factors GATA-1/2, PU.1 and C/EBPε. We have also identified 17 miRNAs that may regulate the expression of TLRs 4 and 13 during eosinophil differentiation, although we could identify no miRNAs targeting the prominent secretory effector, eosinophil major basic protein.

CONCLUSIONS/SIGNIFICANCE

This is the first study to map changes in miRNA expression in whole BM cultures during the differentiation of eosinophils, and to predict functional links between miRNAs and their target mRNAs for the regulation of eosinophilopoiesis. Our findings provide an important resource that will promote the platform for further understanding of the role of these non-coding RNAs in the regulation of eosinophil differentiation and function.

FIP1L1-PDGFRA-Positive Chronic Eosinophilic Leukemia: A Low-Burden Disease with Dramatic Response to Imatinib - A Report of 5 Cases from South India

Objective: Eosinophilia associated with FIP1L1-PDGFRA rearrangement represents a subset of chronic eosinophilic leukemia and affected patients are sensitive to imatinib treatment. This study was undertaken to learn the prevalence and associated clinicopathologic and genetic features of FIP1L1-PDGFRA rearrangement in a cohort of 26 adult patients presenting with profound eosinophilia (>1.5x10⁹/L).

Materials and Methods: Reverse-transcriptase polymerase chain reaction and gel electrophoresis were used for the detection of FIP1L1-PDGFRA rearrangement.

Results: Five male patients with splenomegaly carried the FIP1L1-PDGFRA gene rearrangement. All patients achieved complete hematological response within 4 weeks of starting imatinib. One patient had previous deep vein thrombosis and 1 patient had cardiomyopathy, which improved with steroids and imatinib. Conventional cytogenetics was normal in all these patients. No primary resistance to imatinib was noted.

Conclusion: This study indicates the need to do the FIP1L1-PDGFRA assay in patients with hypereosinophilic syndrome. Prompt treatment of this condition with imatinib can lead to complete hematological response and resolution of the organ damage that can be seen in this setting.

Eosinophilic vasculitis: time for recognition of a new entity?

Hypereosinophilia is part of a group of complex disorders with multisystem involvement. A 23 year old male was admitted to our centre with bilateral popliteal artery and venous thrombosis and impending gangrene of the left forefoot along with deep venous thrombosis of the right lower extremity. Investigations revealed marked peripheral blood eosinophilia (27,669/μL). Bone marrow showed increased eosinophils & eosinophil precursors and no evidence of a clonal disorder. Skin biopsy from the ulcerated lesions showed small vessel vasculitis with intense eosinophilic infiltration. Investigations to look for secondary causes of hypereosinophilia in the form of Antinuclear Antibody, P-Anti Neutrophil Cytoplasmic Antibody (ANCA) and C-ANCA and FIP1L1-PDGFRA, Bcr-Abl and JAK2V617F mutations were negative. The arterial and venous thrombosis and cutaneous vasculitis were linked to the presence of hypereosinophilic syndrome. The patient's illness responded to high dose corticosteroids leading to complete resolution of symptoms. We reviewed the literature on the lesser known entity of eosinophilic vasculitis and its association with thrombosis.

Hypereosinophilic syndrome

OBJECTIVE

To summarize the identified molecular and cellular mechanisms relevant to clinicians evaluating patients with hypereosinophilic syndrome (HES).

DATA SOURCES

Review of relevant peer-reviewed literature.

STUDY SELECTIONS

Studies on the pathogenesis of HES in relation to consensus definitions, disease classification, mechanisms of disease, and diagnosis and treatment are included.

RESULTS

Changes to the definition of HES have been proposed based on recent studies identifying specific cellular and molecular disease phenotypes. Identification of specific mechanisms of disease may have clinical and therapeutic significance. Despite recent advances, in most cases the molecular pathogenesis of HES remains unknown.

CONCLUSION

Identification of specific HES disease mechanisms empowers the practicing clinician to offer specific mechanism-based treatment options to patients with HES in their clinical practice.

World Health Organization-defined eosinophilic disorders: 2014 update on diagnosis, risk stratification, and management

DISEASE OVERVIEW

The eosinophilias encompass a broad range of nonhematologic (secondary or reactive) and hematologic (primary, clonal) disorders with potential for end-organ damage.

DIAGNOSIS

Hypereosinophilia (HE) has generally been defined as a peripheral blood eosinophil count greater than 1,500/mm(3) and may be associated with tissue damage. After exclusion of secondary causes of eosinophilia, diagnostic evaluation of primary eosinophilias relies on a combination of morphologic review of the blood and marrow, standard cytogenetics, fluorescent in situ hybridization, flow immunocytometry, and T-cell clonality assessment to detect histopathologic or clonal evidence for an acute or chronic myeloid or lymphoproliferative disorder.

RISK STRATIFICATION

Disease prognosis relies on identifying the subtype of eosinophilia. After evaluation of secondary causes of eosinophilia, the 2008 World Health Organization establishes a semimolecular classification scheme of disease subtypes including "myeloid and lymphoid neoplasms with eosinophilia and abnormalities of PDGFRA, PDGFRB, or FGFR1', chronic eosinophilic leukemia, not otherwise specified" (CEL, NOS), lymphocyte-variant HE, and idiopathic hypereosinophilic syndrome (HES), which is a diagnosis of exclusion.

RISK-ADAPTED THERAPY

The goal of therapy is to mitigate eosinophil-mediated organ damage. For patients with milder forms of eosinophilia (e.g., <1,500/mm(3)) without symptoms or signs of organ involvement, a watch and wait approach with close-follow-up may be undertaken. Identification of rearranged PDGFRA or PDGFRB is critical because of the exquisite responsiveness of these diseases to imatinib. Corticosteroids are first-line therapy for patients with lymphocyte-variant HE and HES. Hydroxyurea and interferon-alpha have demonstrated efficacy as initial treatment and steroid-refractory cases of HES. In addition to hydroxyurea, second-line cytotoxic chemotherapy agents and hematopoietic cell transplant have been used for aggressive forms of HES and CEL with outcomes reported for limited number of patients. Although clinical trials have been performed with anti-IL-5 (mepolizumab) and anti-CD52 (alemtuzumab) antibodies, their therapeutic role in primary eosinophilic diseases and HES has yet to be established.

Idiopathic eosinophilic pneumonia in children: the French experience

Background

Idiopathic eosinophilic pneumonia is extremely rare in children and adults. We present herein the first series describing the specificities of idiopathic chronic (ICEP) and acute (IAEP) eosinophilic pneumonia in children.

Methods

We retrospectively analyzed all cases of ICEP and IAEP in children that were retrieved from French Reference Centers for rare pediatric lung diseases.

Results

Five cases of pediatric ICEP were identified. Corticosteroid or immunosuppressive therapy dramatically improved the outcome in three cases. The remaining two cases had a persistent interstitial pattern with progressive development of cystic airspace lesions. Three cases of IAEP in adolescents were reported, with one requiring four days of extracorporeal membrane oxygenation.

Conclusion

ICEP is a rare disease with a polymorphic clinical presentation in children. We identified patients with persistent interstitial patterns progressing to cystic airspace regions, for which the boundaries with idiopathic interstitial pneumonias are difficult to establish. We therefore propose a specific pediatric definition and classification algorithm. IAEP in children remains an inflammatory reaction of the lung to an acute toxic exposure, mainly tobacco, as in adults. International studies are required to comprehensively assess the various clinical forms of the disease as well as the appropriate therapeutic regimens.

The eosinophil surface receptor epidermal growth factor-like module containing mucin-like hormone receptor 1 (EMR1): a novel therapeutic target for eosinophilic disorders

BACKGROUND

Although several novel agents are currently in clinical trials for eosinophilic disorders, none has demonstrated efficacy in reducing blood and tissue eosinophilia in all subjects. Additional approaches are clearly needed.

OBJECTIVE

We sought to explore the potential of the human eosinophil surface receptor epidermal growth factor-like module containing mucin-like hormone receptor 1 (EMR1) as a therapeutic target for eosinophilic disorders.

METHODS

EMR1 expression was assessed in blood and bone marrow specimens from eosinophilic and healthy subjects, cell lines, CD34(+) cells differentiated in vitro, and tissue biopsy specimens by using flow cytometry, quantitative PCR, and immunostaining. Eosinophil targeting by a novel, humanized, afucosylated anti-EMR1 IgG1 was evaluated in vitro by using a natural killer cell-mediated killing assay and in vivo in cynomolgus monkeys.

RESULTS

Analysis of blood and bone marrow cells from healthy and eosinophilic donors and in vitro-differentiated CD34(+) cells confirmed restriction of human EMR1 surface and mRNA expression to mature eosinophils. Tissue eosinophils also expressed EMR1. Although EMR1 was highly expressed on eosinophils from all subjects, surface expression was negatively correlated with absolute eosinophil counts (r = -0.46, P < .001), and soluble plasma levels correlated positively with absolute eosinophil counts (r = 0.69, P < .001), suggesting modulation of EMR1 in vivo. Nevertheless, afucosylated anti-EMR1 mAb dramatically enhanced natural killer cell-mediated killing of eosinophils from healthy and eosinophilic donors and induced a rapid and sustained depletion of eosinophils in monkeys.

CONCLUSION

EMR1 expression is restricted to mature blood and tissue eosinophils. Targeting of eosinophils with afucosylated anti-EMR1 antibody shows promise as a treatment for eosinophilic disorders.

Unveiling nonischemic cardiomyopathies with cardiac magnetic resonance

Cardiomyopathy is defined as a heterogeneous group of myocardial disorders with mechanical or electrical dysfunction. Identification of the etiology is important for accurate diagnosis, treatment and prognosis, but continues to be challenging. The ability of cardiac MRI to non-invasively obtain 3D-images of unparalleled resolution without radiation exposure and to provide tissue characterization gives it a distinct advantage over any other diagnostic tool used for evaluation of cardiomyopathies. Cardiac MRI can accurately visualize cardiac morphology and function and also help identify myocardial edema, infiltration and fibrosis. It has emerged as an important diagnostic and prognostic tool in tertiary care centers for work up of patients with non-ischemic cardiomyopathies. This review covers the role of cardiac MRI in evaluation of nonischemic cardiomyopathies, particularly in the context of other diagnostic and prognostic imaging modalities.

Chronic diarrhea, eosinophilic ascites, acute pancreatitis and deep venous thrombosis: A case report

BACKGROUND

Eosinophilic gastroenteritis (EG) is rare and is characterized by recurrent eosinophilic infiltration of the gastrointestinal tract and chronic diarrhea. In this report we present a case of EG with acute pancreatitis and deep vein thrombosis (DVT).

CASE PRESENTATION

A 30 years old male was admitted to our hospital with the complaints of epigastric pain, vomitting and swelling of his left limb for the past six days. He was also having diarrhea for the last several months. He had been evaluated for chronic diarrhea and ascites before he sought the current consultation. Duplex color doppler of left limb showed DVT of distal calf vein. Contrast enhanced CT imaging of abdomen revealed thickening of duodenum, proximal jejunal wall and presence of ascites. Duodenal biopsy showed normal villous pattern with mild inflammation and eosinophilic infiltration. The constellation of clinical presentation, hypereosinophilia, CT and biopsy findings all is in consistence to EG. The patient was treated with prednisolone 20 mg/day for four weeks and tapered slowly. Acute pancreatitis was managed conservatively while DVT was treated with heparin and oral anticoagulants. The patient's diarrhea settled and ascites resolved completely. At follow up, the absolute eosinophil count was 300/μl and the patient was doing well.

CONCLUSION

This case report emphasizes that one should consider these rare disorders during the differential diagnosis of unexplained gastrointestinal symptoms in the presence of hypereosinophilia.

Characteristics and clinical outcome of patients with hypereosinophilia of undetermined significance

The term “hypereosinophilia of undetermined significance” (HE_us) previously known as idiopathic, benign eosinophilia relates to patients who have a long-lasting, unexplained and asymptomatic blood HE. These patients have not been studied so far in terms of demographic characteristics and clinical outcome. The aim of this study was to present the clinical characteristics and outcome of HE_us patients. This is a retrospective, single-center study of 40 patients with HE_us. All patients underwent the basic and specialized evaluations in order to rule out the most common causes of blood HE, but no abnormalities were detected. Twelve patients with at least moderate blood hypereosinophilia (defined as greater than 3.0 × 10⁹/L) for more than 1-year duration were treated with corticosteroids (CS) to avoid end-organ damage. Twenty-one patients (52 %) had an increased leukocyte count at diagnosis. Median blood eosinophilia was 4.2 × 10⁹/L (range 1.5–55.4). HE > 3.0 × 10⁹/L was demonstrated in 17 patients. 65 % of studied population had an increased serum IgE levels, whereas only 2 % demonstrated an increased serum vitamin B12 levels. A median bone marrow infiltration by eosinophils was 30.5 % (range 11–78.2). All treated patients responded promptly to CS and remained in complete remission while receiving low doses of CS (20 mg/day to 5 mg every 2-day). One patient developed hypereosinophilic syndrome (HES) after 11 years of follow-up. Further studies are needed to define risk factors of HES development. The use of CS for HE_us patients is controversial and should be individualized.

CD8(+) T cells producing IL-3 and IL-5 in non-IgE-mediated eosinophilic diseases

The cytokines IL-5, IL-3, and GM-CSF are crucial for eosinophil development, survival, and function. To better understand their role in non-IgE-mediated eosinophilic diseases, we investigated plasma levels of these cytokines as well as cytokine expression in peripheral blood T cells. While we did not find any evidence for an involvement of T-cell-derived GM-CSF, some of these patients did show an increased proportion of IL-5- or IL-3-producing CD4(+) T cells. However, in a significant proportion of patients, IL-5-producing CD8(+) T cells, so-called Tc2 cells, which in healthy donors can only be detected at very low levels, were prominent. Furthermore, increased IL-3 production by CD8(+) T cells was also observed, strongly supporting the notion that CD8(+) T cells, not just CD4(+) T cells, must also be considered as a potential source of the cytokines promoting eosinophilia.

The Differential Diagnosis of Eosinophilia in Neoplastic Hematopathology

Eosinophilia in the peripheral blood is classified as primary (clonal) hematologic neoplasms or secondary (nonclonal) disorders, associated with hematologic or nonhematologic disorders. This review focuses on the categories of hematolymphoid neoplasms recognized by the 2008 World Health Organization Classification of Tumours and Haematopoietic and Lymphoid Tissues that are characteristically associated with eosinophilia. We provide a systematic approach to the diagnosis of these neoplastic proliferations via morphologic, immunophenotypic, and molecular-based methodologies, and provide the clinical settings in which these hematolymphoid neoplasms occur. We discuss recommendations that eosinophilia working groups have published addressing some of the limitations of the current classification scheme.

[IgG4-related disease]

IgG4-related disease is a systemic fibroinflammatory syndrome of unknown etiology characterized by local inflammatory swelling and tumefactive lesions in one or several organs. It unifies several diseases previously thought to be unrelated. Recently, diagnostic criteria for the disease have been formulated and were complemented by an international consensus on histopathological assessment. In general, the disease activity can be rapidly controlled by high doses of prednisolone (0.6 mg/kg body weight); however, relapses, either local or in other regions, are frequent during tapering of the steroid dose. Commonly used steroid-sparing agents are only partially effective. Persistent local inflammatory activity may result in permanent organ damage. In refractory cases rituximab treatment has been used with good success. In the long-term care of affected patients a probable increased risk of malignancies (e.g. solid tumors and lymphoma) requires attention.