Search

Introduction: Studies on eosinophilic gastroenteritis have identified broad spectrums of disease. We aimed to characterize subtypes of disease and ascertain outcomes of each group., Methods: This is a retrospective cohort study from a large tertiary medical center including 35 patients diagnosed with eosinophilic gastroenteritis from 2007 to 2018. We defined 2 groups of patients based on clinical and laboratory findings at presentation. Severe disease was defined as having weight loss at time of presentation, hypoalbuminemia at presentation, serosal disease involvement, or anemia at diagnosis. The remaining patients were labeled as mild disease group. We collected and compared demographic data, clinical features, laboratory findings, an allergy history, and disease course of both cohorts., Results: Among 35 patients with eosinophilic gastroenteritis, 18 patients met the criteria for severe disease and 17 patients for mild disease. Of the patients with severe eosinophilic gastroenteritis, 6 (38%) had remission without chronic symptoms, whereas 10 (63%) had chronic symptoms requiring chronic medical therapy. Of the mild group, 12 patients (80%) had disease remission without chronic medications. An allergy history was more common in the severe disease group (83%) compared with the mild disease group (45%). Prednisone and open capsule budesonide were the most commonly used treatment medications in both groups., Discussion: Patients with eosinophilic gastroenteritis may be characterized into 2 forms. Patients with weight loss at time of presentation, hypoalbuminemia at presentation, serosal disease involvement, or anemia at diagnosis were associated with a chronic disease course requiring chronic medications., (Copyright © 2021 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of The American College of Gastroenterology.)

Eosinophilic colitis (EoC) is a pathological entity associated with abnormal infiltration of colonic mucosa by eosinophilic polynuclear cells (Eo). This is a relatively common pathology in infants and children under 2 years old, but is more rare and has been less studied in adults. EoC can be classified as primary or secondary. Primary EoC is, in the majority of cases, related to an allergic reaction, either IgE-mediated and capable of causing an anaphylactic-type food allergy, or not mediated by IgE and capable of giving rise to food enteropathy. The symptoms for adults with EoC are variable and non-specific, diarrhoea and abdominal pain being the most common signs. There is no histological consensus for the diagnosis of EoC. The presence of over 40 Eo per high-power field (×400) in at least two different colonic segments could be suggested as the criterion for the diagnosis. In adults with primary EoC, skin tests are of limited value and the response to a restrictive diet is less effective than in young children, given that IgE or non-IgE-mediated allergic reactions are rarely identified and EoC generally require medical treatment. There is no consensus on the treatment of EoC, but the potential efficacy of corticosteroids and budesonide has been demonstrated in the vast majority of cases studied., (Copyright © 2020 Elsevier Masson SAS. All rights reserved.)

Antineutrophil cytoplasm antibody (ANCA)-associated vasculitis (AAV) is a term used to describe rare primary systemic vasculitides affecting small and medium-sized blood vessels. AAV diseases which include Granulomatosis with Polyangiitis (GPA), Eosinophilic Granulomatosis with Polyangiitis (EGPA), Microscopic Polyangiitis (MPA) and renal limited ANCA vasculitis. These multisystemic disorders involve upper and lower respiratory tract and kidneys associated with organ damage and long term sequelae. Newer understanding of pathogenesis in AAV have paved the way for clinical research with different biologic therapies. In spite of the paucity of clinical trials in pediatric AAV, the long-term survival of patients with AAV has improved dramatically. International collaborations will help to conduct clinical trials in pediatric AAV and help in better understanding of remission rates, relapse rates, and other outcomes. This article aims to provide a comprehensive review of pediatric AAV with a focus on epidemiology, disease pathogenesis, treatment trials, and prognosis., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Chronic rhinosinusitis with nasal polyps (CRSwNP) is a heterogeneous disorder characterized by chronic sinonasal mucosal inflammation. CRSwNP can be subdivided into two types based on eosinophilic inflammation: eosinophilic CRSwNP (Eos CRSwNP) and non-eosinophilic CRSwNP (Non-Eos CRSwNP). Eos CRSwNP and Non-Eos CRSwNP demonstrate distinct clinical manifestations, treatment outcomes, and cellular and immunopathologic characteristics. However, currently, there is no unified and generally accepted standard to define the Eos CRSwNP. The aim of this review is to compare the advantages and disadvantages of current methods used to classify Eos CRSwNP, in order to lay foundation for further study.

Under normal physiological conditions, eosinophils are present throughout the gastrointestinal tract distal to the squamous oesophagus. Increases in their numbers signify primary and secondary eosinophilic conditions. The rare primary eosinophilic diseases eosinophilic gastroenteritis and eosinophilic colitis affect fewer than ten in 100 000 people, and are characterised by numerous mucosal eosinophils, distributed in sheets and sometimes extending from the mucosa into the submucosa. Pathogenesis of these diseases is poorly understood, but food allergies and intestinal dysbiosis have been implicated. Presentation ranges from vague abdominal symptoms and systemic complaints to, rarely, an acute abdomen with intestinal obstruction. Diagnosis is made from mucosal biopsy samples taken at endoscopy or from surgically resected specimens that demonstrate substantially increased numbers of eosinophils. Eosinophilia secondary to other conditions, such as pathogenic infections, must be excluded. Subtle eosinophilia has also been identified in the duodenum in functional dyspepsia and in the colon in spirochaetosis. Treatment of eosinophilic gastroenteritis and eosinophilic colitis is based on evidence from case reports and small case series, and first-line therapy includes empirical food-elimination diets and single courses of steroids, whereas relapsing or refractory disease might respond to steroid-sparing immunosuppressive agents and biological agents. The progression of disease in eosinophilic gastroenteritis and eosinophilic colitis is variable: a considerable number of patients have just one episode without relapse, whereas others have relapsing-remitting or chronic disease. Primary and secondary eosinophilia in the gastrointestinal tract is increasingly recognised as a clinical conundrum waiting to be solved., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

CME: Mepolizumab, an Additional Therapeutic Agent for Severe Asthma Abstract. The challenging therapy of severe uncontrollable bronchial asthma aims primarily at sufficient symptom control and the minimization of the exacerbation rate. If, despite extended drug therapy, symptom control is very difficult to achieve, biologics should preferably be used instead of corticosteroid therapy. The aim of this article is to point out these different asthma therapy pathways and to describe diagnostic criteria as well as practical experiences through application in patients.

Eosinophilic gastrointestinal diseases (EGIDs), including eosinophilic gastroenteritis and eosinophilic colitis, have been increasing in prevalence in Western countries in recent years. Eosinophils are normally scanty in the gastrointestinal tract, and increased numbers of eosinophils can denote pathology. Normal values for tissue eosinophils vary widely between different segments of the colon, thus location of the biopsy is critically important for the interpretation of findings. However, no standard diagnostic criteria have been proposed for the diagnosis of eosinophilic gastroenteritis or eosinophilic colitis. Gut eosinophilia encompasses entitites that are predominantly immunoglobulin E (IgE)-mediated, the primary EGIDs and those that are secondary and not IgE-mediated. A final diagnosis of eosinophilic gastrointestinal diseases requires careful pathological assessment, clinical correlation and exclusion of several differential diagnoses.

Eosinophilic pustular folliculitis (EPF) is a non-infectious inflammatory dermatosis of unknown etiology that principally affects the hair follicles. There are three variants of EPF: (i) classic EPF; (ii) immunosuppression-associated EPF, which is subdivided into HIV-associated (IS/HIV) and non-HIV-associated (IS/non-HIV); and (iii) infancy-associated EPF. Oral indomethacin is efficacious, especially for classic EPF. No comprehensive information on the efficacies of other medical management regimens is currently available. In this study, we surveyed regimens for EPF that were described in articles published between 1965 and 2013. In total, there were 1171 regimens; 874, 137, 45 and 115 of which were applied to classic, IS/HIV, IS/non-HIV and infancy-associated EPF, respectively. Classic EPF was preferentially treated with oral indomethacin with efficacy of 84% whereas topical steroids were preferred for IS/HIV, IS/non-HIV and infancy-associated EPF with efficacy of 47%, 73% and 82%, respectively. Other regimens such as oral Sairei-to (a Chinese-Japanese herbal medicine), diaminodiphenyl sulfone, cyclosporin and topical tacrolimus were effective for indomethacin-resistant cases. Although the preclusion of direct comparison among cases was one limitation, this study provides a dataset that is applicable to the construction of therapeutic algorithms for EPF., (© 2016 Japanese Dermatological Association.)

Background: Chronic rhinosinusitis (CRS) is likely a biologically heterogeneous disease process. Current guidelines propose subclassification using polyp status while others propose using mucosal eosinophilia. We hypothesized that appropriate CRS subclassification would increase homogeneity of baseline symptoms, and identify characteristic symptoms of each subtype., Methods: A total of 57 CRS patients undergoing surgery prospectively completed a preoperative battery of 73 questions relating to symptoms including the 22-item Sino-Nasal Outcome Test (SNOT-22) and 29-item Patient-Reported Outcomes Measurement Information System (PROMIS-29) general quality of life (QOL) measures. Eosinophilic cationic protein (ECP) levels were determined from ethmoid, uncinate, and polyp tissue homogenates using enzyme-linked immunosorbent assay (ELISA) and normalized to total protein. Patients were classified as eosinophilic (eCRS) or non-eosinophilic (neCRS) using a 95th percentile threshold established from control tissue from 82 patients without CRS. Separate pairwise comparisons were performed on patient-reported symptoms using polyp and eosinophilic status., Results: Of the 57 patients, 28 had CRS with nasal polyps (CRSwNP); 27 of 57 patients had eCRS (CRSwNP, n = 21; CRS without nasal polyps [CRSsNP], n = 6). CRSwNP patients had increased need to blow nose, frequency of nasal congestion, more severe difficulty breathing through nose, more severe nasal discharge, but less cough (p < 0.05). eCRS patients had more bothersome loss of taste/smell, ear pain, sneezing, severe difficulty breathing through nose, and severe nasal congestion compared to neCRS patients (p < 0.05)., Conclusion: Subclassifying CRS with symptoms alone is difficult with neither polyp status nor eosinophilia giving a distinctive clinical symptom profile. However, certain symptoms may help otolaryngologists identify CRS subtypes, which may help guide future treatments. Further validation and evaluation of prognosis following treatment is required to evaluate appropriate means of subclassifying CRS., (© 2015 ARS-AAOA, LLC.)

Disease Overview: The eosinophilias encompass a broad range of non-hematologic (secondary or reactive) and hematologic (primary, clonal) disorders with potential for end-organ damage., Diagnosis: Hypereosinophilia 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 semi-molecular 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 hypereosinophilia, and idiopathic hypereosinophilic syndrome (HES), which is a diagnosis of exclusion., Risk-Adapted Therapy: The goal of the 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 hypereosinophilia 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 numbers 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., (© 2015 Wiley Periodicals, Inc.)

Eosinophilic pustular folliculitis (EPF) is characterized by a non-infectious infiltration of eosinophils in the hair follicles. It has three variants: (i) classic EPF; (ii) immunosuppression-associated EPF, which herein is subdivided into HIV-associated (IS/HIV) and non-HIV-associated (IS/non-HIV); and (iii) infancy-associated EPF (I-EPF). The rarity of EPF has hindered our understanding of this entity. To examine the characteristics of EPF, with respect to age, sex, race, and chronology, published in case reports to date, we queried PubMed using the following terms: ("eosinophilic pustular folliculitis" [All Fields] OR "eosinophilic folliculitis" [All Fields]) AND ("1965/1/1" [PDAT]: "2013/12/31" [PDAT]). Additional Japanese cases were collected from Igaku Chuo Zasshi through Ichushi-Web, JDream III, and secondhand quotations from domestic periodicals published in Japan. Proceedings were excluded. The PubMed search produced 275 citations containing 358 cases of EPF (224 men, 132 women, and two of unspecified sex); these cases involved classic EPF (101 Japanese and 81 non-Japanese), IS/HIV (4 Japanese and 85 non-Japanese), IS/non-HIV (4 Japanese and 20 non-Japanese), and I-EPF (4 Japanese and 59 non-Japanese). Ichushi generated an additional 148 citations containing 207 cases of Japanese (148 men and 59 women), which included cases of classic EPF (181 cases), IS/HIV (14 cases), IS/non-HIV (9 cases), and I-EPF (3 cases). There was no sex difference in the classic EPF cases reported between 2003 and 2013, whereas IS/HIV, IS/non-HIV, and I-EPF were predominated by men. There is room for reconsideration of sex differences, particularly with regard to classic EPF. The rarity and specificity of I-EPF in Japan may reflect a state of uncertainty about this entity., (© 2015 Japanese Dermatological Association.)

Recent studies have suggested the existence of a patient population with esophageal eosinophilia that responds to proton pump inhibitor therapy. These patients are being referred to as having proton pump inhibitor responsive esophageal eosinophilia (PPI-REE), which is currently classified as a distinct and separate disease entity from both gastroesophageal reflux disease (GERD) and eosinophilic esophagitis (EoE). The therapeutic effect of proton pump inhibitor (PPI) on PPI-REE is thought to act directly at the level of the esophageal mucosa with an anti-inflammatory capacity, and completely independent of gastric acid suppression. The purpose of this manuscript is to review the mechanistic data of the proposed immune modulation/anti-inflammatory role of the PPI at the esophageal mucosa, and the existence of PPI-REE as a distinct disease entity from GERD and EoE.

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., (Copyright © 2014 Wiley Periodicals, Inc.)

Purpose of Review: Eosinophils play an important role in the pathogenesis of allergic, infectious and malignant diseases. Over the last decade, new diagnostic tools and treatment modalities have led to the re-evaluation of the existing definition of eosinophilic disorders. This review discusses a recent proposal for new terminology and classification of hypereosinophilia. The results of targeted therapy for hypereosinophilia-related disorders are also summarized., Recent Findings: A panel of multidisciplinary experts agreed on unifying definitions and criteria of eosinophilia-associated disorders and created a new classification of hypereosinophilia-related conditions based on clinical, haematological and laboratory findings as well as the underlying cause of hypereosinophilia. Recent results of the treatment of idiopathic hypereosinophilic syndrome (HES) with the anti-interleukin 5 monoclonal antibody mepolizumab showed its efficacy and manageable safety profile. The treatment of platelet-derived growth factor alpha (PDGFRA)-positive HES with imatinib demonstrated long-lasting efficacy and low likelihood of drug resistance., Summary: The unifying terminology and definitions should aid physicians caring for patients with hypereosinophilia. Despite much progress, serum biomarkers correlate with disease severity and predict responses to treatment that are needed. There is also a great need for understanding and specific therapy for PDGFRA-negative HES.

Morphea or localized scleroderma is a distinctive inflammatory disease that leads to sclerosis of the skin and subcutaneous tissues. It comprises a number of subtypes differentiated according to their clinical presentation and the structure of the skin and underlying tissues involved in the fibrotic process. However, classification is difficult because the boundaries between the different types of morphea are blurred and different entities frequently overlap. The main subtypes are plaque morphea, linear scleroderma, generalized morphea, and pansclerotic morphea. With certain exceptions, the disorder does not have serious systemic repercussions, but it can cause considerable morbidity. In the case of lesions affecting the head, neurological and ocular complications may occur. There is no really effective and universal treatment so it is important to make a correct assessment of the extent and severity of the disease before deciding on a treatment approach., (Copyright © 2011 Elsevier España, S.L. and AEDV. All rights reserved.)

Objective: To evaluate the clinical features and natural course of disease among patients with mucosal-type eosinophilic gastroenteritis in Thailand., Material and Method: The present study was conducted by retrospectively searching for the ICD-10 code for eosinophilic gastroenteritis (EGE) among medical records for the period 2001-2012. Clinical and pathological specimens were reviewed using the same diagnostic criteria. Appropriate tests were conducted to exclude other secondary causes of EGE. All patients had to have either received empirical treatment for parasitic infections or were tested for parasites in the stool. After the diagnosis had been established, each patient received 30-40 mg/day of oral prednisoloneforfour weeks, which was tapered down as clinical status improved. All patients were followed up by monitoring clinical symptoms and relevant laboratory findings. Patients who did not maintain follow-up appointments were contacted by telephone and asked about their clinical symptoms., Results: Seventeen patients with a diagnosis of mucosal-type E (6 male, 11 female, M:F ratio 1:1.83) were found. Mean age at the time of presentation was 52.5 +/- 13.04 years. Four patients (23.5%) had either allergic or atopic conditions. Chronic diarrhea and weight loss were the most common initial presentation in 16 patients (94.1%). Microscopically and macroscopically, bloody diarrhea was observed in 13 cases (76.5%). Four patients were found to have protein-losing enteropathy. Peripheral eosinophilia was found in 10 patients (58.8%) with absolute eosinophil counts between 744 and 23,550 cells/mm3. Eight of these had an absolute eosinophil count in the hypereosinophilic range (> 1,500 cells/mm3). All patients treated with prednisolone treatment showed symptomatic improvement within four weeks. One patient's symptom resolved spontaneously, without treatment. Thirteen patients relapsed during the tapering-off of prednisolone. Seven patients showed complete remission. Three patients subsequently developed cancer (lung, breast, and bladder) after EGE was diagnosed., Conclusion: EGE, although uncommon, is present in Thailand, where parasitic infections continue to be a significant public-health problem.

Context: The advent of molecular tools capable of subclassifying eosinophilia has changed the diagnostic and clinical approach to what was classically called hypereosinophilic syndrome., Objectives: To review the etiologies of eosinophilia and to describe the current diagnostic approach to this abnormality., Data Sources: Literature review., Conclusion: Eosinophilia is a common, hematologic abnormality with diverse etiologies. The underlying causes can be broadly divided into reactive, clonal, and idiopathic. Classically, many cases of eosinophilia were grouped together into the umbrella category of hypereosinophilic syndrome, a clinical diagnosis of exclusion. In recent years, an improved mechanistic understanding of many eosinophilias has revolutionized the way these disorders are understood, diagnosed, and treated. As a result, specific diagnoses can now be assigned in many cases that were previously defined as hypereosinophilic syndrome. Most notably, chromosomal rearrangements, such as FIP1L1-PDGFRA fusions caused by internal deletions in chromosome 4, are now known to be associated with many chronic eosinophilic leukemias. When present, these specific molecular abnormalities predict response to directed therapies. Although an improved molecular understanding is revolutionizing the treatment of patients with rare causes of eosinophilia, it has also complicated the approach to evaluating and treating eosinophilia. Here, we review causes of eosinophilia and present a framework by which the practicing pathologist may approach this diagnostic dilemma. Finally, we consider recent cases as clinical examples of eosinophilia from a single institution, demonstrating the diversity of etiologies that must be considered.

Since Wells and Smith first described cases of eosinophilic cellulitis (Wells syndrome; WS) in 1979, it has been noted that some but not all patients with WS present with eosinophilia. In the face of idiopathic persistent eosinophilia patients will also then fall within the hypereosinophilic syndrome (HES), which represents a multifarious spectrum of disorders of varying severity, causes and outcomes. In this article we propose that patients who present within the HES spectrum with cutaneous findings of WS and with no extracutaneous disease be classified as having 'persistent hypereosinophilia with Wells syndrome' (PHEWS)., (© The Author(s). CED © 2012 British Association of Dermatologists.)

Eosinophilic pustular folliculitis (EPF), also known as Ofuji's disease, is an inflammatory dermatosis that was first described in Japan in 1970. More than 300 cases have been reported so far, and 113 Japanese cases have been reported in Japan since 1980. To comprehend the characteristics of Japanese EPF cases, we classified these cases into three types: classic, immunosuppression-associated (IS-EPF), and infancy-associated (I-EPF). Trends in age of onset and in distribution and characterization of eruptions differed between the types. We found 91 cases of classic EPF (mean age, 39.7 years), consisting of 66 males (73%) and 25 females (27%), in most of which eruptions primarily affected the face; 18 cases of IS-EPF (44.2 years), consisting of 15 males (83%) and three females (17%), in which eruptions affected the face less predominantly; and four cases of I-EPF (7.0 years), consisting of two males (50%) and two females (50%), primarily affecting the scalp. The number of IS-EPF cases has increased since the late 1990s, reflecting the increasing number of HIV-positive patients in Japan. Systemic non-steroidal anti-inflammatory drugs were effective in more than 70% of cases. Dimethyl diphenyl sulfone, antibiotics including minocycline, psoralen plus ultraviolet A therapy and ultraviolet B treatments worked in some cases. Topical steroids and tacrolimus were also effective in some cases of EPF, while topical indomethacin was less effective., (© 2012 Japanese Dermatological Association.)

Eosinophilia is an important indicator of various neoplastic and nonneoplastic conditions. Depending on the underlying disease and mechanisms, eosinophil infiltration can lead to organ dysfunction, clinical symptoms, or both. During the past 2 decades, several different classifications of eosinophilic disorders and related syndromes have been proposed in various fields of medicine. Although criteria and definitions are, in part, overlapping, no global consensus has been presented to date. The Year 2011 Working Conference on Eosinophil Disorders and Syndromes was organized to update and refine the criteria and definitions for eosinophilic disorders and to merge prior classifications in a contemporary multidisciplinary schema. A panel of experts from the fields of immunology, allergy, hematology, and pathology contributed to this project. The expert group agreed on unifying terminologies and criteria and a classification that delineates various forms of hypereosinophilia, including primary and secondary variants based on specific hematologic and immunologic conditions, and various forms of the hypereosinophilic syndrome. For patients in whom no underlying disease or hypereosinophilic syndrome is found, the term hypereosinophilia of undetermined significance is introduced. The proposed novel criteria, definitions, and terminologies should assist in daily practice, as well as in the preparation and conduct of clinical trials., (Copyright © 2012 American Academy of Allergy, Asthma & Immunology. Published by Mosby, Inc. All rights reserved.)

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 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 hypereosinophilia, 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 hypereosinophilia 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 numbers 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., (Copyright © 2012 Wiley Periodicals, Inc.)

Background and Objective: Asthma can be classified as eosinophilic or non-eosinophilic based on the cell profile of induced sputum. This classification can help determine whether corticosteroid treatment is indicated. We assessed the stability of these phenotypes over time and with different treatment regimens., Methods: Clinically stable, non-smoking, asthmatic adults were enrolled in one of two studies. In study one, induced sputum cell counts from 28 subjects were analysed after 4 weeks without corticosteroid treatment and after 6 week treatments with placebo, regular inhaled beta-agonist, inhaled corticosteroid, and combined beta-agonist and corticosteroid. In study two, sputum from 26 subjects with non-eosinophilic asthma was analysed after 12 weeks of placebo and after four 2-week corticosteroid washouts. Sputum with <2% eosinophils was classified as non-eosinophilic., Results: Sputum classification changed frequently in both studies. In study one, only one of eight participants with non-eosinophilic sputum after placebo treatment remained non-eosinophilic throughout. In study two, all of participants had at least one eosinophilic sputum sample, despite the fact that all had been non-eosinophilic at recruitment. Neutrophilic asthma was uncommon in both studies and was also inconsistent., Conclusions: The phenotypic classification of asthma changes frequently. A diagnosis of non-eosinophilic asthma should not be based on a single sputum sample., (© 2011 The Authors. Respirology © 2011 Asian Pacific Society of Respirology.)

The discovery of therapeutically relevant mutations involving platelet-derived growth factor receptors alpha and beta (PDGFRA and PDGFRB) changed the way we evaluate and treat patients with clonal eosinophilia. Despite our improved understanding of the pathobiology of clonal eosinophilia, more than 50% of patients are diagnosed with idiopathic disease, 10% to 20% with a clonal myeloid disorder, and the remainder with a lymphocytic variant. The World Health Organization classification of tumors recognized the importance of a semi-molecular classification of eosinophilic myeloid disorders and divided them into two major subgroups: (1) myeloid and lymphoid neoplasms with eosinophilia and abnormalities of PDGFRA, PDGFRB, or fibroblast growth factor receptor 1 (FGFR1); and (2) chronic eosinophilic leukemia, not otherwise specified. A key challenge remains the identification of tyrosine kinase responsive molecular lesions in patients in whom the pathogenesis of clonal eosinophilia remains unclear., (Copyright © 2012 Elsevier Inc. All rights reserved.)

Peripheral and tissue eosinophilia are usually associated with a variety of inflammatory, malignant, and infectious conditions. As the presence of eosinophils in the tissues may cause significant cellular damage to vital organs such as the heart, tissue eosinophilia should be diagnosed and treated promptly. One operative way to evaluate eosinophilic disorders is to classify them into extrinsic and intrinsic. While extrinsic eosinophilic disorders are usually due to the production of eosinopoietic factors derived from T cells or tumor cells, the intrinsic types generally are the result of genetic mutations in the eosinophilic lineage. As we understand more the biology of eosinophils, only a few eosinophilic disorders remain idiopathic. The purpose of this article is to help the clinician classify in an operational manner most eosinophilic disorders, using the extrinsic and intrinsic model. This may facilitate not only a better understanding of the role of eosinophils in these disorders, but also help the systematic clinical work-up and potential treatment of affected patients.

We describe 3 siblings who suffered from marked eosinophilia with organ involvement. One sibling, who experienced cervical lymphadenopathy and peripheral neuropathy with eosinophilia (5,834 cells/μL) following bronchial asthma, was diagnosed with Churg-Strauss syndrome (CSS) according to the criteria of the American College of Rheumatology. Another sibling, who suffered from severe asthma with persistent polyarthritis and eosinophilia (2,496 cells/μL), was also diagnosed with CSS according to the criteria of the Japanese Ministry of Health, Labour and Welfare. The remaining sibling, who had eosinophilic pleuritis with peripheral blood eosinophilia (699 cells/μL), did not fulfill the widely used criteria for CSS or hypereosinophilic syndrome (HES) ; however, he fit the newly proposed criteria for HES. Glucocorticoid treatment relieved their symptoms. Although the diagnoses and the criteria used for diagnosis differed between the siblings, all 3 patients showed common features such as eosinophilia with organ involvement that required treatment, indicating the possibility of familial eosinophilia (FE). Furthermore, the clinical features observed differed substantially from those of previously reported FE patients, therefore, these 3 siblings may be affected by a type of FE distinguishable from those previously described.

Accurate diagnosis of eosinophilic lung diseases is essential to optimizing patient outcomes, but remains challenging. Signs and symptoms frequently overlap among the disorders, and because these disorders are infrequent, expertise is difficult to acquire. Still, these disorders are not rare, and most clinicians periodically encounter patients with one or more of the eosinophilic lung diseases and need to understand how to recognize, diagnose, and manage these diseases. This review focuses on the clinical features, general diagnostic workup, and management of the eosinophilic lung diseases., (Copyright © 2011 Elsevier Inc. All rights reserved.)

Despite recent attempts to define and classify patients with marked eosinophilia and features consistent with myeloproliferative disease, areas of controversy remain. These are particularly apparent in situations in which multiple lineages are involved in a clonal process and clinical manifestations are overlapping. Although the introduction of new molecular diagnostics and targeted therapies has begun to clarify the boundaries between some of these disorders, several questions remain with respect to the classification of patients with myeloproliferative hypereosinophilic syndrome (HES) of unknown etiology.

Acquired eosinophilia is operationally categorized into secondary, clonal, and idiopathic types. Causes of secondary eosinophilia include parasite infections, allergic or vasculitis conditions, drugs, and lymphoma. Clonal eosinophilia is distinguished from idiopathic eosinophilia by the presence of histologic, cytogenetic, or molecular evidence of an underlying myeloid malignancy. The World Health Organization classification system for hematologic malignancies recognizes 2 distinct subcategories of clonal eosinophilia: chronic eosinophilic leukemia, not otherwise specified and myeloid/lymphoid neoplasms with eosinophilia and mutations involving platelet-derived growth factor receptor alpha/beta or fibroblast growth factor receptor 1. Clonal eosinophilia might also accompany other World Health Organization-defined myeloid malignancies, including chronic myelogenous leukemia, myelodysplastic syndromes, chronic myelomonocytic leukemia, and systemic mastocytosis. Hypereosinophilic syndrome, a subcategory of idiopathic eosinophilia, is defined by the presence of a peripheral blood eosinophil count of 1.5 x 10(9)/L or greater for at least 6 months (a shorter duration is acceptable in the presence of symptoms that require eosinophil-lowering therapy), exclusion of both secondary and clonal eosinophilia, evidence of organ involvement, and absence of phenotypically abnormal and/or clonal T lymphocytes. The presence of the latter defines lymphocytic variant hyper eosinophilia, which is best classified under secondary eosinophilia. In the current review, we provide a simplified algorithm for distinguishing the various causes of clonal and idiopathic eosinophilia and discuss current therapy, including new drugs (imatinib mesylate, alemtuzumab, and mepolizumab).

Eosinophilia represents a complex clinical problem, the management of which is based on case history and clinical examination. Allergy, parasitic infection or inflammation may then be identified or malignancy suspected. In some cases, representing a haematologic disorder, clonality is demonstrated only by specific tests. The diagnostic and therapeutic approach, including a new classification for eosinophilia, is reviewed, and the importance of molecular biological technique is highlighted. Unexplained eosinophilia should be managed in collaboration with a haematology department.

Recently the World Health Organization (WHO), in collaboration with the European Association for Haematopathology and the Society for Hematopathology, published a revised and updated edition of the WHO Classification of Tumors of the Hematopoietic and Lymphoid Tissues. The 4th edition of the WHO classification incorporates new information that has emerged from scientific and clinical studies in the interval since the publication of the 3rd edition in 2001, and includes new criteria for the recognition of some previously described neoplasms as well as clarification and refinement of the defining criteria for others. It also adds entities-some defined principally by genetic features-that have only recently been characterized. In this paper, the classification of myeloid neoplasms and acute leukemia is highlighted with the aim of familiarizing hematologists, clinical scientists, and hematopathologists not only with the major changes in the classification but also with the rationale for those changes.

Eosinophilia is a recurrent feature and diagnostic clue in several hematologic malignancies. In stem cell- and myelopoietic neoplasms, eosinophils are derived from the malignant clone, whereas in lymphoid neoplasms and reactive states, eosinophilia is usually triggered by eosinopoietic cytokines. Myeloid neoplasms typically presenting with eosinophilia include chronic myeloid leukemia, chronic eosinophilic leukemia (CEL), other myeloproliferative neoplasms, some acute leukemias, advanced mast cell disorders, and rare forms of myelodysplastic syndromes. Diagnostic evaluations in unexplained eosinophilia have to take these diagnoses into account. In such patients, a thorough hematologic work-up including bone marrow histology and immunohistochemistry, cytogenetics, molecular markers, and a complete staging of potentially affected organ systems has to be initiated. Endomyocardial fibrosis, the most dangerous cardiovascular complication of the hypereosinophilic state, is frequently detected in PDGFR-mutated neoplasms, specifically in FIP1L1/PDGFRA+ CEL, but is usually not seen in other myeloid neoplasms or reactive eosinophilia, even if eosinophilia is recorded for many years. Treatment of hypereosinophilic patients depends on the variant of disease, presence of end organ damage, molecular targets, and the overall situation in each case. In a group of patients, oncogenic tyrosine kinases (TK) such as FIP1L1/PDGFRA, can be employed as therapeutic targets by using imatinib or other TK-blocking agents.

Purpose of Review: This review is timely and relevant because rhinosinusitis is a disease process that is heterogeneous in its clinical and pathologic manifestations. Therefore, no one causative factor has been identified that fully accounts for all rhinosinusitis. The purpose of this review is to provide a succinct update of rhinosinusitis classification, pathophysiology, and management given the new movement toward evidence-based guidelines., Recent Findings: The term rhinosinusitis reflects the concurrent inflammatory and infectious processes that affect the nasal passages and the contiguous paranasal sinuses. The most recent classification scheme is intended primarily to guide clinical research and divides rhinosinusitis into four categories: acute bacterial rhinosinusitis, chronic sinusitis with nasal polyposis, chronic rhinosinusitis with nasal polyposis, and allergic fungal rhinosinusitis. The goals of treatment include reduction of mucosal edema, reestablishment of sinus ventilation, and eradication of infecting pathogens. Multiple therapies are available for the management of chronic rhinosinusitis, including antibiotics, hypertonic and isotonic saline irrigations or sprays, topical and systemic glucocorticords, antileukotriene agents, and endoscopic sinus surgery., Summary: Rhinosinusitis is a common medical problem that interferes with patient quality of life and loss of work productivity. Because of the heterogeneity that underlies its pathology, no one treatment regimen exists for the management of rhinosinusitis.

Diagnosis of eosinophilic gastrointestinal diseases is based on morphological evaluation with regard to localization and density of eosinophil infiltration of the mucosa and/or deeper parts of the oesophagus, stomach, and bowel in biopsy or resection specimens. As with eosinophils in any tissue, in the majority of diseases they are probably a sequel of acute inflammation and do not indicate any specific disease. Eosinophil morphology includes intact cells with bilobated nuclei and eosinophil granules in the cytoplasm and extracellular tissue following activation/degranulation. There is no fixed number of eosinophils that can be used as a cut-off criterion to define disease. Associated histopathological features observed in eosinophilic gastrointestinal disease depend on the site of manifestation and primary disease. Eosinophils are typically increased in allergy-associated colitis in adults and allergic proctocolitis in infants, eosinophilic gastroenteritis and eosinophilic oesophagitis. Their presence can also suggest a drug-induced eosinophilia or the presence of a parasitic infection. In general, eosinophils are increased in inflammatory bowel disease (IBD). They are seen in reflux oesophagitis, coeliac disease, and microscopic and infectious colitis. Eosinophils may be a feature of polyarteriitis nodosa and Churg-Strauss syndrome, and can accompany connective-tissue disease as well as malignant lymphomas and adenocarcinomas of gastrointestinal mucosa.

During the last decade, clinical practice saw a rapid increase of patients with esophageal eosinophilia who were thought to have gastroesophageal reflux disease (GERD) but who did not respond to medical and/or surgical GERD management. Subsequent studies demonstrated that these patients had a "new" disease termed eosinophilic esophagitis (EE). As recognition of EE grew, so did confusion surrounding diagnostic criteria and treatment. To address these issues, a multidisciplinary task force of 31 physicians assembled with the goal of determining diagnostic criteria and making recommendations for evaluation and treatment of children and adults with suspected EE. Consensus recommendations were based upon a systematic review of the literature and expert opinion. EE is a clinicopathological disease characterized by (1) Symptoms including but not restricted to food impaction and dysphagia in adults, and feeding intolerance and GERD symptoms in children; (2) > or = 15 eosinophils/HPF; (3) Exclusion of other disorders associated with similar clinical, histological, or endoscopic features, especially GERD. (Use of high dose proton pump inhibitor treatment or normal pH monitoring). Appropriate treatments include dietary approaches based upon eliminating exposure to food allergens, or topical corticosteroids. Since EE is a relatively new disease, the intent of this report is to provide current recommendations for care of affected patients and defining gaps in knowledge for future research studies.

Background: The broad and overlapping clinical manifestations of D816V KIT-associated systemic mastocytosis with eosinophilia and FIP1L1/PDGFRA-associated chronic eosinophilic leukemia (CEL), coupled with the increase in activated eosinophils and mast cells seen in both disorders, have led to confusion in the nomenclature. It is of paramount importance, however, to distinguish between these 2 groups of patients because of differences in clinical sequelae, prognoses, and selection of treatment., Objective: We thus sought to identify clinical and laboratory features that could be used to distinguish these 2 diagnoses., Methods: We compared 12 patients with D816V-positive systemic mastocytosis with eosinophilia with 17 patients with FIP1L1/PDGFRA-positive CEL. Distinguishing features were used to create a risk factor scoring system., Results: This system correctly classified 16 of 17 FIP1L1/PDGFRA-positive patients with CEL and all 12 patients with systemic mastocytosis with eosinophilia. Thirty-four FIP1L1/PDGFRA-positive patients described in the literature were also classified using this system, and although a complete set of data was not available for any of the historical patients, 21 were correctly classified., Conclusion: These results reinforce the hypothesis that the FIP1L1/PDGFRA gene fusion and D816V-KIT mutation cause distinct clinical syndromes., Clinical Implications: This novel diagnostic approach should prove helpful in clinical practice in the evaluation of patients with increased mast cells and peripheral eosinophilia.

Eosinophilic inflammatory responses occur in association with multiple disorders. Although the initial cause and the affected organs vary among the different eosinophilic disorders, there are only 2 major pathways that mediate eosinophilia: (1) cytokine-mediated increased differentiation and survival of eosinophils (extrinsic eosinophilic disorders), and (2) mutation-mediated clonal expansion of eosinophils (intrinsic eosinophilic disorders). Independent from the original trigger, the most common cause of eosinophilia is the increased generation of IL-5-producing T cells. In some cases, tumor cells are the source of eosinophil hematopoietins. The intrinsic eosinophilic disorders are characterized by mutations in pluripotent or multipotent hematopoietic stem cells leading to chronic myeloid leukemias with eosinophils as part of the clone. Here, we propose a new classification of eosinophilic disorders on the basis of these obvious pathogenic differences between the 2 groups of patients. We then discuss many known eosinophilic disorders, which can be further subdivided by differences in T-cell activation mechanisms, origin of the cytokine-producing tumor cell, or potency of the mutated stem cell. Interestingly, many subgroups of patients originally thought to have the idiopathic hypereosinophilic syndrome can be integrated in this classification.

Background: We have previously reported the results of a randomized, double-blind, placebo-controlled trial that found the intake of yogurt supplemented with a probiotic strain, Bifidobacterium longum BB536, alleviates symptoms and affects blood parameters in individuals with Japanese cedar pollinosis (JCPsis) during the pollen season., Objective: In the present study, fecal microbiota were investigated to examine whether any changes occur during the pollen season and whether any influence is exerted by probiotic intake., Methods: Yogurt either with BB536 (BB536 yogurt) or without BB536 (placebo yogurt) was administered for 14 weeks at 2 x 100 g per day to 40 subjects (17 men, 23 women) with a clinical history of JCPsis. Fecal samples were obtained from 23 subjects (placebo group, n=13; BB536 group, n=10) before and during the intervention (weeks 4, 9 and 13) and fecal microbiota were analyzed using terminal-restriction fragment length polymorphism and real-time polymerase chain reaction (PCR) methods., Results: From the fluctuation patterns of terminal-restriction fragments, the Bacteroides fragilis group and bifidobacteria were among the species that changed most with pollen dispersion. Real-time PCR analyses indicated that the cell numbers of the B fragilis group increased significantly along with pollen dispersion in both BB536 and placebo groups. Cell numbers of bifidobacteria were significantly higher in the BB536 group compared with the placebo group (P < .05 at weeks 4 and 9). The ratio of cell numbers of the B fragilis group to bifidobacteria increased significantly during the pollen season in the placebo group (P < .01 at weeks 9 and 14), but not in the BB536 group. An in vitro study using peripheral blood mononuclear cells from JCPsis subjects indicated that strains of the B fragilis group induced significantly more helper T cell (T(H)) type2 cytokines (interleukin [IL]-6) but fewer T(H)1 cytokines (IL-12 and interferon) compared with those of bifidobacteria., Conclusions: These results suggest a relationship between fluctuation in intestinal microbiota and pollinosis allergy. Furthermore, intake of BB536 yogurt appears to exert positive ihfluences on the formation of anti-allergic microbiota.

Before the 1990s, lack of evidence for a reactive cause of hypereosinophilia or chronic eosinophilic leukemia (e.g. presence of a clonal cytogenetic abnormality or increased blood or bone marrow blasts) resulted in diagnosticians characterizing such nebulous cases as 'idiopathic hypereosinophilic syndrome (HES)'. However, over the last decade, significant advances in our understanding of the molecular pathophysiology of eosinophilic disorders have shifted an increasing proportion of cases from this idiopathic HES 'pool' to genetically defined eosinophilic diseases with recurrent molecular abnormalities. The majority of these genetic lesions result in constitutively activated fusion tyrosine kinases, the phenotypic consequence of which is an eosinophilia-associated myeloid disorder. Most notable among these is the recent discovery of the cryptic FIP1L1-PDGFRA gene fusion in karyotypically normal patients with systemic mast cell disease with eosinophilia or idiopathic HES, redefining these diseases as clonal eosinophilias. Rearrangements involving PDGFRA and PDGFRB in eosinophilic chronic myeloproliferative disorders, and of fibroblast growth factor receptor 1 (FGFR1) in the 8p11 stem cell myeloproliferative syndrome constitute additional examples of specific genetic alterations linked to clonal eosinophilia. The identification of populations of aberrant T-lymphocytes secreting eosinophilopoietic cytokines such as interleukin-5 establish a pathophysiologic basis for cases of lymphocyte-mediated hypereosinophilia. This recent revival in understanding the biologic basis of eosinophilic disorders has permitted more genetic specificity in the classification of these diseases, and has translated into successful therapeutic approaches with targeted agents such as imatinib mesylate and recombinant anti-IL-5 antibody.

A 43-year-old man developed a skin eruption characterized by 'macules with blisters' typical to Stevens-Johnson syndrome, as well as erosions of the lips and buccal mucosa, 2 weeks after he had started treatment with lamotrigine. He had a fever (39.6 degrees C), elevated liver enzymes and atypical lymphocytes in the peripheral blood. This undoubtedly reflects a case of Stevens-Johnson syndrome induced by lamotrigine, but it can also fulfill the criteria of anticonvulsant hypersensitivity syndrome or drug rash with eosinophilia and systemic signs. A case that precisely fits the definition of two syndromes that have different characteristics, different treatments and different prognoses indicates that there is a flaw in the classification.

According to contemporary vernacular, when the cutaneous manifestations of drug rash with eosinophilia and systemic signs (DRESS) syndrome are those of Stevens-Johnson syndrome (SJS) or toxic epidermal necrolysis (TEN), the condition is defined as "DRESS syndrome with severe cutaneous reactions". In this article, we have presented arguments for and against including patients with skin lesions of the SJS/TEN syndromes who also have fever (practically all of the patients) and internal organ involvement (most of the patients) under the definition of DRESS syndrome. After weighing the arguments for and against this alteration of definition, we conclude that it makes more sense for patients with SJS/TEN to be classified as such and not be lumped together under the misleading label of DRESS syndrome.

Acquired blood eosinophilia is considered either a primary or a secondary phenomenon. Causes of secondary (ie, reactive) eosinophilia include tissue-invasive parasitosis, allergic or inflammatory conditions, and malignancies in which eosinophils are not considered part of the neoplastic process. Primary eosinophilia is classified operationally into 2 categories: clonal and idiopathic. Clonal eosinophilia stipulates the presence of either cytogenetic evidence or bone marrow histological evidence of an otherwise classified hematologic malignancy such as acute leukemia or a chronic myeloid disorder. Idiopathic eosinophilia is a diagnosis of exclusion (ie, not secondary or clonal). Hypereosinophilic syndrome is a subcategory of idiopathic eosinophilia; diagnosis requires documentation of both sustained eosinophilia (absolute eosinophil count > or = 1500 cells/microL for at least 6 months) and target organ damage (eg, involvement of the heart, lung, skin, or nerve tissue). Genetic mutations involving the platelet-derived growth factor receptor genes (PDGFR-alpha and PDGFR-beta) have been pathogenetically linked to clonal eosinophilia, and their presence predicts treatment response to imatinib. Accordingly, cytogenetic and/or molecular investigations for the presence of an imatinib-sensitive molecular target should accompany current evaluation for primary eosinophilia. In the absence of such a drug target, specific treatment is dictated by the underlying hematologic malignancy in cases of clonal eosinophilia; however, the initial treatment of choice for symptomatic patients with hypereosinophilic syndrome is prednisone and/or interferon alfa.

A pathogenetic mutation, FIP1L1-PDGFRA, that results from an interstitial chromosome 4q12 deletion, leads to a constitutive activation of the platelet-derived growth factor receptor-alpha (PDGFRA) tyrosine kinase as well as a disease phenotype that mimics both the hypereosinophilic syndrome (HES) and systemic mast cell disease associated with eosinophilia (SMCD-eos). Complete remissions, in response to treatment with low-dose imatinib mesylate (100 mg/day or less) have now been documented in all cases of FIP1L1-PDGFRA(+) eosinophilic disorder as well as other eosinophilic disorders that carry activation mutations of the PDGFRB gene that is located on chromosome 5q33. Furthermore, response to therapy has been rapid (within days) and durable. Interestingly, imatinib mesylate treatment, at a higher dose level (400 mg/day), might induce either partial or short-lived complete remissions in HES that is not associated with the aforementioned PDGFR mutations. These observations make it necessary to re-examine current disease classification and treatment algorithms in eosinophilic disorders.