Chapter 061. Disorders of Granulocytes and Monocytes (Part 11)

Eosinophilia Eosinophilia is the presence of 500 eosinophils per µL of blood and is common in many settings besides parasite infection. Significant tissue eosinophilia can occur without an elevated blood count. A common cause of eosinophilia is allergic reaction to drugs (iodides, aspirin, sulfonamides, nitrofurantoin, penicillins, and cephalosporins). Allergies such as hay fever, asthma, eczema, serum sickness, allergic vasculitis, and pemphigus are associated with eosinophilia. Eosinophilia also occurs in collagen vascular diseases (e.g., rheumatoid arthritis, eosinophilic fasciitis, allergic angiitis, and periarteritis nodosa) and malignancies (e.g., Hodgkins disease; mycosis fungoides; chronic myeloid leukemia; and cancer of the lung, stomach, pancreas,...
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Chapter 061. Disorders of Granulocytes and Monocytes (Part 11) Chapter 061. Disorders of Granulocytes and Monocytes (Part 11) Eosinophilia Eosinophilia is the presence of >500 eosinophils per µL of blood and iscommon in many settings besides parasite infection. Significant tissue eosinophiliacan occur without an elevated blood count. A common cause of eosinophilia isallergic reaction to drugs (iodides, aspirin, sulfonamides, nitrofurantoin,penicillins, and cephalosporins). Allergies such as hay fever, asthma, eczema,serum sickness, allergic vasculitis, and pemphigus are associated witheosinophilia. Eosinophilia also occurs in collagen vascular diseases (e.g.,rheumatoid arthritis, eosinophilic fasciitis, allergic angiitis, and periarteritisnodosa) and malignancies (e.g., Hodgkins disease; mycosis fungoides; chronicmyeloid leukemia; and cancer of the lung, stomach, pancreas, ovary, or uterus), aswell as in Jobs syndrome and CGD. Eosinophilia is commonly present in thehelminthic infections. IL-5 is the dominant eosinophil growth factor. Therapeuticadministration of the cytokines IL-2 and GM-CSF frequently leads to transienteosinophilia. The most dramatic hypereosinophilic syndromes are Loefflerssyndrome, tropical pulmonary eosinophilia, Loefflers endocarditis, eosinophilicleukemia, and idiopathic hypereosinophilic syndrome (50,000–100,000/µL). The idiopathic hypereosinophilic syndrome represents a heterogeneousgroup of disorders with the common feature of prolonged eosinophilia of unknowncause and organ system dysfunction, including the heart, central nervous system,kidneys, lungs, gastrointestinal tract, and skin. The bone marrow is involved in allaffected individuals, but the most severe complications involve the heart andcentral nervous system. Clinical manifestations and organ dysfunction are highlyvariable. Eosinophils are found in the involved tissues and likely cause tissuedamage by local deposition of toxic eosinophil proteins such as eosinophil cationicprotein and major basic protein. In the heart, the pathologic changes lead tothrombosis, endocardial fibrosis, and restrictive endomyocardiopathy. The damageto tissues in other organ systems is similar. Some cases are due to mutationsinvolving the platelet-derived growth factor receptor, and these are extremelysensitive to the tyrosine kinase inhibitor imatinib. Glucocorticoids, hydroxyurea,and IFN-α each have been used successfully, as have therapeutic antibodiesagainst IL-5. Cardiovascular complications are managed aggressively. The eosinophilia-myalgia syndrome is a multisystem disease, withprominent cutaneous, hematologic, and visceral manifestations, that frequentlyevolves into a chronic course and can occasionally be fatal. The syndrome ischaracterized by eosinophilia (eosinophil count >1000/µL) and generalizeddisabling myalgias without other recognized causes. Eosinophilic fasciitis,pneumonitis, and myocarditis; neuropathy culminating in respiratory failure; andencephalopathy may occur. The disease is caused by ingesting contaminants in L-tryptophan–containing products. Eosinophils, lymphocytes, macrophages, andfibroblasts accumulate in the affected tissues, but their role in pathogenesis isunclear. Activation of eosinophils and fibroblasts and the deposition of eosinophil-derived toxic proteins in affected tissues may contribute. IL-5 and transforminggrowth factor βhave been implicated as potential mediators. Treatment iswithdrawal of products containing L-tryptophan and the administration ofglucocorticoids. Most patients recover fully, remain stable, or show slow recovery,but the disease can be fatal in up to 5% of patients. Eosinopenia Eosinopenia occurs with stress, such as acute bacterial infection, and aftertreatment with glucocorticoids. The mechanism of eosinopenia of acute bacterialinfection is unknown but is independent of endogenous glucocorticoids, since itoccurs in animals after total adrenalectomy. There is no known adverse effect ofeosinopenia. Hyperimmunoglobulin E–Recurrent Infection Syndrome The hyperimmunoglobulin E–recurrent infection syndrome, or Jobssyndrome, is a rare multisystem disease in which the immune system, bone, teeth,lung, and skin are affected. Abnormal chemotaxis is a variable feature. Themolecular basis for this syndrome is still not known, but some cases show clearautosomal dominant transmission with linkage to 4q. Patients with this syndromehave characteristic facies with broad nose, kyphoscoliosis and osteoporosis, andeczema. The primary teeth erupt normally but do not deciduate, often requiringextraction. Patients develop recurrent sinopulmonary and cutaneous infections thattend to be much less inflamed than appr ...