Eosinophil cationic protein in nasal washes from wheezing children serum and infants and Jim Mark Ingram, MD, Gary P. Rakes, MD, Gates E. Hoover, MD, Thomas A. E. Platts-Mills, MD, PhD, and Peter W. Heymann, MD From the Departments of Pediatricsand Internal Medicine, University of Virginia Health Sci- ences Center, Charlottesville Objective: To compare eosinophil counts and concentrations of eosinophil cat- ionic protein (ECP) in serum and nasal wash fluid from wheezing infants and chil- dren with those from age-matched children without respiratory tract symptoms. Design: A case-control study of 71 children treated for wheezing and 59 control subjects in the University of Virginia Pediatric Emergency Depadment. The patients ranged from 2 months to 16 years of age. Eosinophil numbers and ECP concen- trations were assessed in serum and nasal washes. Total serum IgE was measured and the radioallergosorbent test was used to measure IgE antibody to common inhalant allergens. Results: Among children less than the age of 2 years, markedly elevated levels of ECP (>200 ng/ml) were measured in nasal washes from 9 (41%) of 22 wheezing patients and I (6%) of 17 control subjects (p <0.03). None of these children had a positive radioallergosorbent test result for IgE antibody to common aeroaller- gens or a nasal smear containing 10% eosinophils. Few of the wheezing children under 2 years of age had either increased concentrations of total IgE or ECP in their serum or an elevated total blood eosinophil count. After the age of 2 years, the percentage of patients with nasal ECP levels greater than 200 ng/ml was also sig- nificantly higher in wheezing children than in control subjects (p <0.001), and a positive correlation was observed between ECP concentrations in their nasal washes and other eosinophil responses (total blood eosinophil counts, serum ECP levels, and nasal eosinophil counts). Conclusion: Increased concentrations of ECPwere detected in nasal washes from wheezing infants and children, indicating that eosinophils may contribute to the pathogenesis of airway inflammation in some children who wheeze early in life. (J PEDIATR 1995;127:558-64) Supported by National Institutes of Health grants AI-24261 and AI-20565 and by National Institutes of Health Asthma Center grant IU01-AI-34607 and General Clinical Research Center grant M01RR00847. Submitted for publication Jan. 3, 1995; accepted May 5, 1995. Reprint requests: Peter W. Heymann, MD, Department of Pediat- rics, Building MR-4, Room 5061, University of Virginia Health Sciences Center, Charlottesville, VA 22908. Copyright © 1995 by Mosby-Year Book, Inc. 0022-3476/95/$5.00 + 0 9/20/66219 The strong association between immediate hypersensitivity to inhaled allergens and asthma in school-aged children and I ECP , Eosinophiliccationic protein I RAST Radioallergosorbent test RSV Respiratory syncytial virus in adults is well recognized.l' 2 During the first 2 years of life, however, viral infections, especially those caused by respi- ratory syncytial virus, are the dominant risk factor for 558