To the Editor.
—Eosinophilia is a fairly common clinical finding and is well known in its association with a variety of disorders. However, after the known causes have been ruled out, there remains a small group of patients with persistent hypereosinophilia of unknown cause. Transient hypereosinophilia occurred in a newborn as the product of a pregnancy complicated by Löffler's syndrome. The mother continued to have chronic hypereosinophilia during the next decade.
Report of a Case.
—A 26-year-old woman was hospitalized in 1971 during the third trimester of her second pregnancy with cough, dyspnea, pulmonary infiltrates, and hypereosinophilia. Her medical history included hospitalizations for pneumonia and meningitis at age 5. A cardiac murmur of unknown type was noted during her first pregnancy in 1966. Physical findings included a grade 3/6 murmur of mitral stenosis and a grade 2/6 murmur of aortic regurgitation. The lungs were clear to auscultation. The tip of