Complete remission of hypereosinophilic syndrome after interferon-alpha therapy: report of a case and literature review

Idiopathic eosinophilia complicated with cryptococcal meningitis: a case report

Idiopathic eosinophilia, characterized by unexplained peripheral blood eosinophilia after ruling out secondary causes, is an extremely rare condition. Cryptococcal meningitis is a life-threatening opportunistic infection that primarily affects immunocompromised individuals, such as those with advanced AIDS or leukemia. In this report, we present a unique case of idiopathic eosinophilia concurrent with cryptococcal meningitis, which, to the best of our knowledge, is the first such case described globally.

World Health Organization and International Consensus Classification of eosinophilic disorders: 2024 update on diagnosis, risk stratification, and management

DISEASE OVERVIEW

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

DIAGNOSIS

Hypereosinophilia (HE) has generally been defined as a peripheral blood eosinophil count greater than 1.5 × 109/L, and may be associated with tissue damage. After the exclusion of secondary causes of eosinophilia, diagnostic evaluation of primary eosinophilias relies on a combination of various tests. They include morphologic review of the blood and marrow, standard cytogenetics, fluorescence in situ hybridization, molecular testing and flow immunophenotyping to detect histopathologic or clonal evidence for an acute or chronic hematolymphoid neoplasm.

RISK STRATIFICATION

Disease prognosis relies on identifying the subtype of eosinophilia. After evaluation of secondary causes of eosinophilia, the 2022 World Health Organization and International Consensus Classification endorse a semi-molecular classification scheme of disease subtypes. This includes the major category "myeloid/lymphoid neoplasms with eosinophilia and tyrosine kinase gene fusions" (MLN-eo-TK), and the MPN subtype, "chronic eosinophilic leukemia" (CEL). Lymphocyte-variant HE is an aberrant T-cell clone-driven reactive eosinophila, and idiopathic hypereosinophilic syndrome (HES) 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., <1.5 × 109/L) 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. Pemigatinib was recently approved for patients with relapsed or refractory FGFR1-rearranged neoplasms. Corticosteroids are first-line therapy for patients with lymphocyte-variant HE and HES. Hydroxyurea and interferon-α have demonstrated efficacy as initial treatment and in steroid-refractory cases of HES. Mepolizumab, an interleukin-5 (IL-5) antagonist monoclonal antibody, is approved by the U.S Food and Drug Administration for patients with idiopathic HES. Cytotoxic chemotherapy agents, and hematopoietic stem cell transplantation have been used for aggressive forms of HES and CEL, with outcomes reported for limited numbers of patients. Targeted therapies such as the IL-5 receptor antibody benralizumab, IL-5 monoclonal antibody depemokimab, and various tyrosine kinase inhibitors for MLN-eo-TK, are under active investigation.

World Health Organization-defined eosinophilic disorders: 2022 update on diagnosis, risk stratification, and management

DISEASE OVERVIEW

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

DIAGNOSIS

Hypereosinophilia (HE) has generally been defined as a peripheral blood eosinophil count greater than 1.5 × 10⁹ /L. After exclusion of secondary causes of eosinophilia, diagnostic evaluation of primary eosinophilias relies on morphologic review of the blood and marrow, standard cytogenetics, fluorescence in situ hybridization, next generation sequencing gene assays, and flow immunophenotyping to detect histopathologic or clonal evidence for an acute or chronic hematolymphoid neoplasm.

RISK STRATIFICATION

Disease prognosis relies on identifying the subtype of eosinophilia. After evaluation of secondary causes of eosinophilia, the 2016 World Health Organization endorses a semi-molecular classification scheme of disease subtypes. This includes the major category "myeloid/lymphoid neoplasms with eosinophilia and rearrangement of PDGFRA, PDGFRB, or FGFR1 or with PCM1-JAK2", and the myeloproliferative neoplasm subtype, "chronic eosinophilic leukemia, not otherwise specified" (CEL, NOS). Lymphocyte-variant HE is an aberrant T-cell clone-driven reactive eosinophila, and idiopathic hypereosinophilic syndrome (HES) 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 (eg, < 1.5 × 10⁹ /L) 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-α have demonstrated efficacy as initial treatment and in steroid-refractory cases of HES. Mepolizumab, an interleukin-5 (IL-5) antagonist monoclonal antibody, was recently approved by the US Food and Drug Administration for patients with idiopathic HES. The use of the IL-5 receptor antibody benralizumab, as well as other targeted therapies such as JAK2 and FGFR1 inhibitors, is under active investigation.

Use of H-1 Antihistamine in Dermatology: More than Itch and Urticaria Control: A Systematic Review

H-1 antihistamines are commonly used in dermatological practice for itch and urticaria control. The widespread expression of H-1 receptor on different cells in the skin and various biologic functions of H-1 antihistamines indicate the possible treatment potentials of H-1 antihistamines in dermatology. A literature search was performed on PubMed and Embase, targeting articles reporting use of antihistamine for purposes other than itch and urticaria control in dermatological practice. Several off-label usages of antihistamines were identified, including alopecia, acne, Darier disease, eosinophilic dermatoses, paraneoplastic dermatoses, psoriasis, lichen nitidus, radiation dermatitis, skin dysesthesia, and cutaneous malignancies. Additional benefits were observed when H-1 antihistamines were used either alone or in combination with other therapeutic modalities. Although various novel uses of H-1 antihistamines have been uncovered, the evidence level of most included studies is weak. Further randomized control trials are warranted to better evaluate the efficacy and dosage of H-1 antihistamine for dermatological disorders.

Steroid Resistant Hypereosinophilic Syndrome Suspected to Be Caused by Aberrant T-cell Subset

A 53-year-old male presented with cough, skin rash and lymphadenopathies complicated with hypereosinophilia (HE) in the blood, and patchy shadows in both lungs on chest computed tomography. Reactive causes for HE were excluded, and no clinical or laboratory features of myeloproliferative disorders could be found. HE caused by aberrant T-cell subsets was suspected because of serum hyper-immunoglobulin E level, and organ involvement of skin and lungs, though we could show neither aberrant T-cell surface markers nor T-cell receptor gene rearrangement. In the course of steroid monotherapy, tolerable maintenance dose could not be attained and the steroid-sparing agents of hydroxycarbamide, cyclosporine and interferon-α were introduced. However, the therapeutic response was inadequate, and organ involvement of lungs and intestinal tract developed. HE caused by aberrant T-cell subsets has steroid resistance and a risk of malignant transition, and we considered this progressive steroid refractoriness to be a sign of such a transition. Cytotoxic chemotherapy or bone marrow transplantation will likely be the next treatment modality in this patient.

Hypereosinophilic syndromes in the precision medicine era: clinical, molecular aspects and therapeutic approaches (targeted therapies)

Introduction: Hypereosinophilic syndromes are a heterogeneous group of disorders that may be associated with life-threatening organ injury as a result of tissues infiltration by eosinophils. The main goal of therapy is to mitigate eosinophil-mediated organ damage. When possible, therapy should be directed at the underlying etiology. However, even in the absence of any known cause, when organ damage is present, hypereosinophilia must be treated promptly and aggressively to reduce potential morbidity and mortality.Areas covered: Conventional therapies, including corticosteroids, hydroxyurea (hydroxycarbamide) and interferon-alpha, have shown variable efficacy and a non-negligible toxicity emphasizing the need of new therapeutic strategies based on drugs with different mechanisms of action.Expert opinion: Tyrosine kinase inhibitors have a central role among targeted therapies of hypereosinophilic syndromes. Imatinib, initially empirically used based on its activity in chronic myeloid leukemia, achieved preliminary excellent results further confirmed in large series of patients. Third-generation tyrosine kinase inhibitors such as ponatinib, while active in vitro and in vivo in animals, still deserve confirmation in properly designed clinical trials. In addition, clinical investigation on monoclonal antibodies against interleukin-5, interleukin-5Rα, IgE, and CD52 represents a promising area of research.

World Health Organization-defined eosinophilic disorders: 2019 update on diagnosis, risk stratification, and management

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 1.5 × 10⁹ /L, and may be associated with tissue damage. After exclusion of secondary causes of eosinophilia, diagnostic evaluation of primary eosinophilias relies on a combination of various tests. They include morphologic review of the blood and marrow, standard cytogenetics, fluorescence in situ-hybridization, flow immunophenotyping, and T-cell clonality assessment to detect histopathologic or clonal evidence for an acute or chronic hematolymphoid neoplasm.

RISK STRATIFICATION

Disease prognosis relies on identifying the subtype of eosinophilia. After evaluation of secondary causes of eosinophilia, the 2016 World Health Organization endorses a semi-molecular classification scheme of disease subtypes. This includes the major category "myeloid/lymphoid neoplasms with eosinophilia and rearrangement of PDGFRA, PDGFRB, or FGFR1 or with PCM1-JAK2", and the MPN subtype, "chronic eosinophilic leukemia, not otherwise specified" (CEL, NOS). Lymphocyte-variant hypereosinophilia is an aberrant T-cell clone-driven reactive eosinophila, and idiopathic hypereosinophilic syndrome (HES) 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 (eg, <1.5 × 10⁹ /L) 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-alfa have demonstrated efficacy as initial treatment and in steroid-refractory cases of HES. In addition to hydroxyurea, second line cytotoxic chemotherapy agents, and hematopoietic stem cell transplantation have been used for aggressive forms of HES and CEL, with outcomes reported for limited numbers of patients. The use of antibodies against interleukin-5 (IL-5) (mepolizumab), the IL-5 receptor (benralizumab), as well as other targets on eosinophils remains an active area of investigation.

Idiopathic hypereosinophilic syndrome with cutaneous involvement: a comparative review of 32 cases

Although idiopathic hypereosinophilic syndrome (HES) is uncommon, we studied the clinical characteristics of this disorder in patients with cutaneous involvement. We chronicle the case of a patient with diffuse skin rash due to idiopathic HES from our clinical experience. Furthermore, a systematic literature search of the medical databases PubMed and Google Scholar was conducted. A total of 32 cases fulfilled the inclusion criteria. The data on patients' characteristics, epidemiology, clinical features, diagnosis, treatment and outcome were collected and analysed. This review illustrates that physicians should maintain a high index of clinical suspicion for idiopathic HES in patients presenting with dermatological lesions and hypereosinophilia, without an obvious cause. Randomised clinical trials are warranted to outline a generalised and efficient therapeutic approach in these patients. Additionally, this paper highlights the need for population-based studies to delineate the magnitude and scope of this association.

A case report of Löffler endocarditis in idiopathic hypereosinophilic syndrome: recovery is possible

Introduction

Hypereosinophilic syndrome (HES) is a myeloproliferative disorder characterized by persistent eosinophilia that is associated with damage to multiple organs.

Case Presentation

Herein, we describe a case of left ventricular (LV) Löffler endocarditis on top of idiopathic HES leading to inflow and outflow obstruction. The posterior mitral leaflet was involved in the fibrotic process leading to severe mitral valve regurgitation. There was a mural thrombus in the left ventricle, which resulted in thrombo-embolic complications in the form of lower limb ischaemia. The patient was treated with high-dose corticosteroids and anticoagulants with significant improvement of his cardiac condition.

Discussion

In patients with persistent hypereosinophilia, thorough workup is recommended to identify any possible primary cause and detect associated end-organ damage. Treatment should be started as early as possible after establishing the diagnosis to reduce morbidity and prevent complications. Corticosteroids are the first-line therapy that usually cause a rapid reduction in the level of the eosinophilia and must be started promptly if cardiac involvement is present to attain rapid reduction in the eosinophil level and reverse the cardiac damage.

World Health Organization-defined eosinophilic disorders: 2017 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 has generally been defined as a peripheral blood eosinophil count greater than 1500/mm³ 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 2016 World Health Organization endorses a semi-molecular classification scheme of disease subtypes which includes the major category "myeloid/lymphoid neoplasms with eosinophilia and rearrangement of PDGFRA, PDGFRB, or FGFR1 or with PCM1-JAK2," and the "MPN subtype, chronic eosinophilic leukemia, not otherwise specified" (CEL, NOS). Lymphocyte-variant hypereosinophilia is an aberrant T-cell clone-driven reactive eosinophila, and idiopathic hypereosinophilic syndrome (HES) 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., < 1500/mm³ ) 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. The use of antibodies against interleukin-5 (IL-5) (mepolizumab), the IL-5 receptor (benralizumab), and CD52 (alemtuzumab), as well as other targets on eosinophils remains an active area of investigation.

World Health Organization-defined eosinophilic disorders: 2015 update on diagnosis, risk stratification, and management

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.

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.

Löffler endocarditis: a rare cause of acute cardiac failure

We describe a patient with acute cardiogenic shock due to cardiac involvement in idiopathic hypereosinophilic syndrome (Löffler endocarditis). At the echocardiography, there was a huge mass in the left ventricular cavity, resulting in inflow- and outflow tract obstruction. The posterior leaflet of the mitral valve apparatus was completely embedded in a big (organized) thrombus mass. The patient was treated with high dose corticosteroids, however without effect. Partial remission was achieved after treatment with hydroxycarbamide. He was also treated with anticoagulants and high dose beta-blockers. The patient’s condition improved remarkably after correction of the mitral valve insufficiency by a mitral valve bioprosthesis.

World Health Organization-defined eosinophilic disorders: 2012 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 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.

A Case Report of Eosinophilic Esophagitis Accompanying Hypereosinophilic Syndrome

Hypereosinophilic syndrome is a blood disorder characterized by the overproduction of eosinophils in the bone marrow with persistent peripheral eosinophilia, associated with organ damage by the release of eosinophilic mediators. Although HES can involve multiple organ systems, GI tract involvement is very rare. Few cases of HES presenting with gastritis or enteritis have been reported worldwide. To date, HES presenting with esophagus involvement has only been reported once. Here, we present a 39-year-old Hispanic female patient with history of HES presenting with complaints of dysphagia and generalized pruritus.

World Health Organization-defined eosinophilic disorders: 2011 update on diagnosis, risk stratification, and management

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 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 niche in primary eosinophilic diseases and HES have yet to be established.

Primary eosinophilic disorders: a concise review

Primary eosinophilic disorders include hypereosinophilic syndrome (HES); chronic eosinophilic leukemia, not otherwise categorized (CEL-NOC); platelet-derived growth factor receptor (PDGFR)-rearranged myeloid neoplasms; and other myeloid malignancies associated with prominent blood eosinophilia. According to the World Health Organization consensus criteria, the diagnosis of HES requires the absence of clonal cytogenetic or molecular markers of an underlying myeloid or lymphoid neoplasm. CEL-NOC constitutes an HES-like phenotype associated with an abnormal karyotype or excess blasts in blood (> 2%) or bone marrow (> 5%). HES and CEL-NOC are considered distinct from molecularly defined eosinophilic disorders, such as those associated with activating mutations of PDGFR (PDGFRA and PDGFRB) and fibroblast growth factor receptor-1. This is an important distinction because PDGFR-mutated but not other eosinophilic neoplasms are effectively treated with imatinib. Current management in HES includes observation only for asymptomatic patients with no evidence of organ damage, systemic corticosteroid therapy for acute control of symptoms, and interferon-alfa-2a or hydroxyurea as steroid-sparing agents. In patients with HES who are refractory to usual therapy and have life-threatening disease complications, the use of investigational drugs such as alemtuzumab or mepolizumab might be considered, but data on long-term efficacy and safety are limited.

Hypereosinophilic syndrome in childhood: clinical and molecular features of two cases

Hypereosinophilic syndrome (HES) represents a heterogeneous group of diseases, some of which are being clarified by recent advances in molecular genetics. It is very rare in children. Uncertainties in classification and lack of prospective studies make therapeutic decisions difficult. The authors report two cases of HES in which steroid therapy was effective.

Oral mucosa lesions in hypereosinophilic syndrome--an update

Hypereosinophilic syndrome (HES) is a rare disorder characterized by persistent and marked eosinophilia. Some HES forms have a poor prognosis, either because of end-organ damage (particularly endomyocardial fibrosis), or because of associated myeloid leukemia or malignant T-cell lymphoma. Oral mucosa ulcerations can be early clinical signs in severe forms. They are discrete, round or oval, sometimes confluent ulcers or erosions, located on non-keratinized, unattached oral mucosa. In the last 15 years a better understanding of eosinophil biology has led to a new clinical classification of HES. The lymphocytic form is characterized by T-lymphocyte clonality, IL-5 production, and a possible progression to T-cell lymphoma. Oral lesions are more frequently associated with the myeloproliferative form, characterized by an increased risk of developing myeloid malignancies and a good response to a recent anti-tyrosine kinase therapy (imatinib mesylate). The target of imatinib is a novel kinase resulting from an 800-kb deletion on chromosome 4. Recently, the resulting FIP1L1-PDGFRalpha fusion gene was characterized as a marker of response to imatinib. Exclusion of other erosive ulcerative oral disease and early recognition of HES in patients with oral ulcerations, and precise characterization of the lymphocytic or myeloproliferative form are therefore important to rapidly initiate an effective therapy.

Treatment of hypereosinophilic syndromes with prednisone, hydroxyurea, and interferon

The hypereosinophilic syndromes continue to challenge our clinical acumen and skills. Prednisone, hydroxyurea, and interferon alpha 2b are three of the oldest agents that allow control of eosinophilia and its devastating clinical consequences. They still work. As our experience with them has grown, it has become evident that use of these agents in combination will control eosinophilia in most patients. Moreover, with time, the doses can frequently be reduced. Even with the advent of newer agents for treatment of hypereosinophilic syndromes, these three medications still afford an excellent, cost-effective avenue for disease management.

Management of hypereosinophilic syndrome: a prospective study in the era of molecular genetics

Hypereosinophilic syndrome (HES) is a heterogeneous group of disorders characterized by unexplained persistent primary eosinophilia causing end-organ damage. We conducted a prospective cohort study of patients fulfilling the diagnostic criteria for HES. Of 20 patients considered eligible for the study, 2 were found to have clonal myeloid disorders, limiting the diagnosis of "true" HES to 18 patients. No patient carried the FIP1L1-PDGFRA fusion gene or other imatinib-responsive translocations. A clonal interleukin-5-producing T-cell population was not detected in any patient. Common manifestations at presentation were pulmonary, cutaneous, and neurologic involvement; serositis; and gastrointestinal involvement. Only 3 patients developed cardiac involvement. Fifteen of the HES patients were administered first-line combined treatment with steroids and hydroxyurea. Nine patients achieved complete response, while 6 attained only partial response. Imatinib was administered to 3 HES patients who had been pretreated with steroids, resulting in complete hematologic and clinical response in 2 patients and no response at all in 1. Further treatment of the latter patient with steroids and hydroxyurea also proved ineffective. We conclude that the therapeutic approach should be individualized according to molecular findings. We consider the coadministration of corticosteroids and hydroxyurea to be an effective combination for the treatment of FIP1L1-PDGFRA-negative HES.

Approach to the Therapy of Hypereosinophilic Syndromes

With the introduction of new diagnostic methods and treatment modalities, it has become increasingly clear that hypereosinophilic syndromes (HES) are a heterogeneous group of disorders for which a single approach to treatment is insufficient. This article discusses current treatment modalities for myeloproliferative HES, idiopathic HES, and lymphocytic-variant HES.

Eosinophilic disorders: molecular pathogenesis, new classification, and modern therapy

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.

Atypical myeloproliferative disorders: diagnosis and management

Myeloid disorders constitute a subgroup of hematological malignancies that is separate from lymphoid disorders. The World Health Organization system for classification of tumors of the hematopoietic system divides myeloid disorders into acute myeloid leukemia and chronic myeloid disorders based on the presence or absence, respectively, of acute myeloid leukemia--defining morphological and cytogenetic features including the presence of 20% or more myeloblasts in either the bone marrow or the peripheral blood. A recently proposed semimolecular classification system for chronic myeloid disorders recognizes 3 broad categories: the myelodysplastic syndrome, classic myeloproliferative disorders (MPD), and atypical MPD. Classic MPD includes polycythemia vera, essential thrombocythemia, myelofibrosis with myeloid metaplasia, and chronic myeloid leukemia. Both myelodysplastic syndrome and BCR/ABL-negative classic MPD were previously discussed as part of the current ongoing symposium on hematological malignancies. The current review focuses on the diagnosis and treatment of both molecularly defined and clinicopathologically assigned categories of atypical MPD: chronic myelomonocytic leukemia, juvenile myelomonocytic leukemia, chronic neutrophilic leukemia, chronic basophilic leukemia, chronic eosinophilic leukemia, idiopathic eosinophilia including hypereosinophilic syndrome, systemic mastocytosis, unclassified MPD, and eosinophilic/mast cell disorders associated with mutations of platelet-derived growth factor receptors alpha (PDGFRA) and beta (PDGFRB), FGFR1, and KIT.

Traitement des hyperéosinophilies

Therapeutic management of blood hypereosinophilia depends on its underlying cause. The cause may be clearly established (parasitic infestation) or more hypothetical (systemic disease). Blood eosinophils often return to normal levels after treatment of either the cause or the associated eosinophilic disease. A targeted approach is more difficult when the cause is unknown (unexplained chronic hypereosinophilia). Various conventional treatments (corticosteroids, hydroxyurea, interferon) have been somewhat effective. The identification of new cellular and molecular markers with diagnostic and pathophysiologic significance makes more rational approaches possible.

Hypereosinophilic syndrome: an update

Hypereosinophilic syndrome (HES) is a rare disorder that is characterized by persistent and marked eosinophilia combined with organ system dysfunction. HES has substantial clinical heterogeneity but can be fatal without treatment, especially in patients who present with a myelodysplastic variant of the disorder. Although the pathophysiology of HES is poorly defined, dysregulation of cytokines (interleukin 5 [IL-5], IL-3, granulocyte-macrophage colony-stimulating factor [GM-CSF]) responsible for the maturation of eosinophils is a primary feature. Of these cytokines, IL-5 appears to have the greatest role in the regulation of eosinophil maturation. There is no Food and Drug Administration-approved treatment for HES as yet; current strategies are designed to lower blood eosinophils and attempt to limit end-organ damage. Historically, corticosteroids and cytotoxic agents have been the mainstays of therapy, with biological response modifiers such as interferon-alpha also effective in some patients. However, despite improvements in survival, available agents have significant limitations in terms of efficacy, tolerability, and long-term toxicity. More recently, new agents directed at specific targets in the pathogenesis of HES have been developed. These include imatinib mesylate, a tyrosine kinase inhibitor, and more recently, mepolizumab, an anti-IL-5 monoclonal antibody. In a small case series of patients, these agents have been shown to produce hematological and clinical responses in patients with HES, although they may be effective in different subsets of patients. These targeted therapies have the potential to improve clinical outcomes and to further the understanding the pathophysiology of this difficult-to-treat condition.

Recurrent Optic Neuritis as the Presenting Manifestation of Primary Hypereosinophilic Syndrome: A Report of Two Cases

Two patients sustained multiple attacks of optic neuritis with persistent visual loss. An elevated eosinophil count was initially considered an incidental finding. Years later, the diagnosis of primary hypereosinophilic syndrome (HES) was confirmed by skin and bone marrow in one patient and by lung biopsy in the other. Treatment with hydroxyurea in one patient and with continuous low-dose prednisone in the other stopped the optic neuritis attacks, resolved systemic manifestations, and stabilized neurologic manifestations. These cases emphasize that primary HES may be a cause of recurrent optic neuritis, and that delay in diagnosis and treatment of primary HES can lead to visual morbidity.

Modern diagnosis and treatment of primary eosinophilia

The recent discovery of an eosinophilia-specific, imatinib-sensitive, karyotypically occult but fluorescence in situ hybridization-apparent molecular lesion in a subset of patients with blood eosinophilia has transformed the diagnostic as well as treatment approach to eosinophilic disorders. Primary (i.e. nonreactive) eosinophilia is considered either "clonal" or "idiopathic" based on the presence or absence, respectively, of either a molecular or bone marrow histological evidence for a myeloid neoplasm. Clonal eosinophilia might accompany a spectrum of clinicopathological entities, the minority of whom are molecularly characterized; Fip1-like-1-platelet-derived growth factor receptor alpha (FIP1L1-PDGFRA(+)) systemic mastocytosis, platelet-derived growth factor receptor beta (PDGFRB)-rearranged atypical myeloproliferative disorder, chronic myeloid leukemia, and the 8p11 syndrome that is associated with fibroblast growth factor receptor 1 (FGFR1) rearrangement. Hypereosinophilic syndrome (HES) is a subcategory of idiopathic eosinophilia and is characterized by an absolute eosinophil count of > or =1.5 x 10(9)/l for at least 6 months as well as eosinophil-mediated tissue damage. At present, a working diagnosis of primary eosinophilia mandates a bone marrow examination, karyotype analysis, and additional molecular studies in order to provide the patient with accurate prognostic information as well as select appropriate therapy. For example, the presence of either PDGFRA or PDGFRB mutations warrants the use of imatinib in clonal eosinophilia. In HES, prednisone, hydroxyurea, and interferon-alpha constitute first-line therapy, whereas imatinib, cladribine, and monoclonal antibodies to either interleukin-5 (mepolizumab) or CD52 (alemtuzumab) are considered investigational. Allogeneic transplantation offers a viable treatment option for drug-refractory cases.

Interferon treatment for hypereosinophilic syndromes and systemic mastocytosis

Hypereosinophilic syndromes (HES) and systemic mastocytosis (SMCD) are heterogeneous disorders with clinical symptoms from local and remote effects of excessive proliferation of eosinophils and mast cells, respectively. Interferon alpha (IFN-alpha), alone or in combination with other medications, can be a useful, and at times life-saving, treatment for patients with HES. Receptors for IFN-alpha are present on eosinophils, and clinical benefits are due to its effect on eosinophil proliferation, migration, activation, and survival. These effects are likely mediated through multiple pathways including, but not limited to, inhibition of eosinophil colony-forming cells, upregulation of IFN-gamma synthesis, and inhibition of production of eosinophil-active cytokines by T cells, mast cells, and mononuclear cells. IFN-alpha has been life-saving for patients with intractable HES that were resistant to prednisone, hydroxyurea, and other agents. Resistance to the eosinopenic effect of IFN-alpha does not develop and the dose of IFN-alpha necessary to maintain control of eosinophilia often decreases with time. The combination of IFN-alpha and hydroxyurea is very useful and allows dosage reduction of IFN-alpha and better control of hypereosinophilia than with either agent alone. The efficacy of IFN-alpha for treatment of SMCD has been more difficult to establish, with both favorable and unfavorable results reported. The disparate results may have resulted from the small number of patients with SMCD treated with IFN-alpha, the use of various criteria for a "successful" treatment outcome, short duration of treatment and follow-up, and the use of modest dosages. In reported series, side effects from IFN-alpha have frequently been dose-limiting. IFN-alpha improves many of the clinical symptoms of SMCD including dermatological, hematological, gastrointestinal, and systemic symptoms associated with histamine release. IFN-alpha has a beneficial effect on skeletal symptoms because of its ability to increase bone density and reduce painful episodes from vertebral fractures. No consistent improvement in bone marrow infiltration by mast cells has been demonstrated except in a recent study employing high dosages of IFN-alpha. A beneficial effect from the combination of IFN-alpha and prednisone has been reported for several patients, suggesting that combined use of these two medications may provide synergism in treatment outcomes.

Combination Therapy With Montelukast and Ketotifen for Arthritis and Rash Resulting From Idiopathic Hypereosinophilic Syndrome

Idiopathic hypereosinophilic syndrome (IHES) is a rare condition of uncertain etiology characterized by marked peripheral blood eosinophilia and organ system dysfunction that cannot be explained by any factor other than the presence of eosinophils or their potentially toxic products. Diagnostic criteria include 1) a sustained eosinophilia greater than 1500/mm for longer than 6 months, 2) absence of other causes of eosinophilia, including parasitic infections and allergic diseases, and 3) multiorgan involvement (ie, lungs, heart, central nervous system, skin, liver, joints). Steroids represent the initial therapeutic approach, although for those patients unresponsive to steroids, cytotoxic chemotherapy should be considered. We describe a case of IHES characterized by polyarticular inflammatory joint involvement, hypereosinophilia, and urticarioid skin manifestations without visceral involvement. Synovial fluid smears as well as pathology of skin lesions and knee synovial membrane confirmed the presence of numerous eosinophils. The patient was successfully treated with a combination therapy of a cysteinyl leukotriene receptor antagonist (montelukast) and ketotifen. Hypereosinophilic syndrome like in this patient is a rare cause of polyarthritis.

A rare case of idiopathic hypereosinophilic syndrome involving the oral cavity associated with the esophagus and gastrointestinal tract

We report the rare case of HES involving oral cavity associated with esophagus, and gastrointestinal tract, which we succeeded in diagnosing precisely through a biopsy specimen obtained from the lip. A 64-year-old man had dysphagia, swelling of the oral mucosa and the posterior cervical muscles, accompanied by an abdominal pain and diarrhea. Peripheral blood cell count showed marked eosinophilia. Computed tomography showed thickening of posterior wall of the pharynx, esophagus, and gastrointestinal tract. Histologic specimen obtained from the lower lip demonstrated a moderate infiltration of eosinophils. His clinical condition was improved by oral prednisolone therapy.

The FIP1L1-PDGFRalpha fusion tyrosine kinase in hypereosinophilic syndrome and chronic eosinophilic leukemia: implications for diagnosis, classification, and management

Idiopathic hypereosinophilic syndrome (HES) and chronic eosinophilic leukemia (CEL) comprise a spectrum of indolent to aggressive diseases characterized by unexplained, persistent hypereosinophilia. These disorders have eluded a unique molecular explanation, and therapy has primarily been oriented toward palliation of symptoms related to organ involvement. Recent reports indicate that HES and CEL are imatinib-responsive malignancies, with rapid and complete hematologic remissions observed at lower doses than used in chronic myelogenous leukemia (CML). These BCR-ABL-negative cases lack activating mutations or abnormal fusions involving other known target genes of imatinib, implicating a novel tyrosine kinase in their pathogenesis. A bedside-to-benchtop translational research effort led to the identification of a constitutively activated fusion tyrosine kinase on chromosome 4q12, derived from an interstitial deletion, that fuses the platelet-derived growth factor receptor-alpha gene (PDGFRA) to an uncharacterized human gene FIP1-like-1 (FIP1L1). However, not all HES and CEL patients respond to imatinib, suggesting disease heterogeneity. Furthermore, approximately 40% of responding patients lack the FIP1L1-PDGFRA fusion, suggesting genetic heterogeneity. This review examines the current state of knowledge of HES and CEL and the implications of the FIP1L1-PDGFRA discovery on their diagnosis, classification, and management.

16. Immunologic lung disease

This review summarizes the recent advances regarding pathogenesis, diagnosis, and treatment of immunological diseases of the lung. Rather than attempt a comprehensive analysis, we have focused on selected diseases that are of particular relevance to the practicing physician, and the material has been organized according to the dominant immunologic mechanisms underlying the disease. Because of the redundancy that characterizes the mammalian immune repertoire, this system of classification inevitably produces overlap but facilitates acquisition of what is otherwise a disparate collection of facts. The principal lung immunologic mechanisms are most broadly classified as innate or adaptive immune processes. Innate immunity includes neutrophils and complement that are important in diseases, such as pneumonia and the acute respiratory distress syndrome. Adaptive immunity involves T and B cells capable of recognizing discrete antigens. T(H)1- and T(H)2-dependent adaptive immune responses underlie some of the most common and important of lung diseases, including tuberculosis and asthma, respectively. Other important immunopathologic processes include granulomatous inflammation that characterizes sarcoidosis and Churg-Strauss vasculitis, and autoimmunity, which is characteristic of antiglomerular basement membrane disease and others.