A 65-year-old French man with no medical history was admitted to the hospital in June 2001 for temperature of 39°C and night sweats evolving for 2 weeks. He denied ingestion of any drug and had traveled to the French West Indies 6 months previously. On hospital admission, the patient appeared fatigued and had lost 5 kg in weight. The physical examination was otherwise unremarkable. The WBC count showed 10,800/μL, with 50% neutrophils, 17% lymphocytes, and 26% eosinophils (absolute count, 2,830/μL). Erythrocyte sedimentation rate was 86 mm/h. C-reactive protein was 85 mg/L (normal > 13 mg/L). Electrolytes, liver function test results, serum creatinine level, and lactate dehydrogenase level were normal. Serum electrophoresis showed an albumin level of 32.8 g/L (normal > 39 g/L); α2-globulin, 9.8 g/L (normal < 7 g/L); and polyclonal γ-globulinemia, 16.9 g/L (normal < 10 g/L). Search for antinuclear, anti-double-stranded DNA, antineutrophil cytoplasmic antibodies, and rheumatoid factor was negative. Infectious inquiry included blood and urine cultures and search for mycobacteria in sputum; serologic study findings for Chlamydia psittaci and Chlamydia pneumoniae, Coxiella burnetii, Legionnella pneumophilia, and Mycoplasma pneumoniae were negative. Chest radiography and thoracoabdominal CT scan showed bilateral hilar and mediastinal lymphadenopathy 2 to 5 cm in diameter, and discrete bilateral pleurisy (Fig 1
). Fiberoptic bronchoscopy demonstrated a diffuse inflammation with a nonspecific inflammation on lung biopsy; direct search for pathogens and culture findings were negative.