Color Atlas of Hematology - Practical Microscopic and Clinical ...

124Abnormalities of the White Cell SeriesElevated Eosinophil and Basophil CountsIn accordance with their physiological role, an increase in eosinophils( 400/µl, i.e. for a leukocyte count of 6000, more than 8% in the differentialblood analysis) is usually due to parasitic attack (p. 5). In the Westernhemisphere, parasitic infestations are investigated on the basis of stoolsamples and serology.Strongyloides stercoralis in particular causes strong, sometimes extreme,elevation of eosinophils (may be up to 50%). However, eosinophilia ofvariable degree is also seen in ameba infection, in lambliasis (giardiasis),schistosomiasis, filariasis, and even malaria.Bacterial and viral infections are both unlikely ever to lead to eosinophiliaexcept in a few patients with scarlet fever, mononucleosis, or infectiouslymphocytosis. The second most common group of causes of eosinophiliaare allergic conditions: these include asthma, hay fever, and various dermatoses(urticaria, psoriasis). This second group also includes druginducedhypersensitivity with its almost infinitely multifarious triggers,among which various antibiotics, gold preparations, hydantoin derivatives,phenothiazines, and dextrans appear to be the most prevalent.Eosinophilia is also seen in autoimmune diseases, especially inscleroderma and panarteritis. All neoplasias can lead to “paraneoplastic”eosinophilia, and in Hodgkin’s disease it appears to play a special role inthe pathology, although it is nevertheless not always present.A specific hypereosinophilia syndrome with extreme values (usually 40%) is seen clinically in association with various combinations ofsplenomegaly, heart defects, and pulmonary infiltration (Loeffler syndrome),and is classified somewhere between autoimmune diseases andmyeloproliferative syndromes. Of the leukemias, CML usually manifestsmoderate eosinophilia in addition to its other typical criteria (see p. 114).When moderate eosinophilia dominates the hematological picture, theterm chronic eosinophilic leukemia is used. Acute, absolute predominanceof eosinophil blasts with concomitant decrease in neutrophils, erythrocytes,and thrombocytes suggests the possibility of the very rare acuteeosinophilic leukemia.Elevated Basophil Counts. Elevation of segmented basophils to more than2–3% or 150/µl is rare and, in accordance with their physiological role inthe immune system regulation, is seen inconsistently in allergic reactionsto food, drugs, or parasites (especially filariae and schistosomes), i.e., usuallyin conditions in which eosinophilia is also seen. Infectious diseasesthat may show basophilia are tuberculosis and chickenpox; metabolic diseaseswhere basophilia may occur are myxedema and hyperlipidemia. Autonomicproliferations of basophils are part of the myeloproliferative