An 81-year-old Japanese man under hemodialysis was admitted complaining of a general fatigue and loss of appetite. He had been taken hemodialysis for three years because of diabetic nephropathy. Before admission, precipitated calcium carbonate, carvedilol, telmisartan/amlodipine besilate and insulin glargine were prescribed. On examination, body temperature of 36.9 8C and blood pressure of 145/77 mmHg. Slight edema was found on the both upper extremities. Laboratory data revealed B type natriuretic peptide (BNP) 56.2 pmol/L, plasma albumin 26 g/L, serum sodium (Na) 133 mmol/L, fasting blood glucose 2.8 mmol/L, serum creatinine (Cr) 561.6 mmol/L and hemoglobin (Hb) 94 g/L. X-ray showed slight pleural effusion. Transthoracic echocardiography revealed slight dilatation of inferior vena cava (IVC: 14.4 mm). Therefore, he was first diagnosed as suffering from heart failure and his general condition was maintained by hemodialysis. Although his WBC count was 6300/mL, eosinophilia was found (26.5%) on the eighth day. Simultaneously his body temperature rose to 39.5 8C. Since bacterial infection was suspected, intravenous administration of ceftriaxone 1 g/day was commenced. But, the body temperature was not suppressed and general fatigue continued. Therefore, the pathogenesis of eosinophilia was explored. Plasma adrenocorticotropic hormone