Deposits of eosinophil granule proteins in eosinophilic cholecystitis and eosinophilic colitis associated with hypereosinophilic syndrome

Summary A case of hypereosinophilic syndrome with eosinophilic colitis, eosinophilic cholecystitis, and increased serum levels of interleukin-5 (IL-5) and soluble interleukin-2 receptor (sIL-2R) is reported. Immunohistochemical studies of cholecystectomy and colon biopsy specimens with monoclonal antibodies, which are specific for activated eosinophils, secreted eosinophil cationic protein (ECP) and for major basic protein (MBP), demonstrated the presence of numerous activated eosinophils, secretion of ECP, and deposition of MBP in areas of tissue damage. These findings suggest that in eosinophilic cholecystitis and eosinophilic colitis, activated eosinophils infiltrate and degranulate in each tissue, releasing eosinophil granule proteins that produce tissue damage.