Immunopathology of chronic rhinosinusitis in young children.

OBJECTIVE Previous investigation demonstrated predominantly lymphocytic inflammation in sinus mucosa of young children with chronic rhinosinusitis (CRS) rather than eosinophilic inflammation typical of adult CRS. Immunohistopathological study was undertaken to define further the cellular response in pediatric CRS. STUDY DESIGN Maxillary mucosal biopsies from children and adults with CRS were stained for CD3 (T lymphocytes), CD4 (helper T lymphocytes), CD8 (cytotoxic T lymphocytes), CD20 (B lymphocytes), CD68 (monocytes/macrophages), CD56 (natural killer cells), kappa and lambda (plasma cells), and myeloperoxidase (MPO; neutrophils). RESULTS Nineteen children with CRS (median age, 3.0 years; range, 1.4-8.2 years) had more CD8+, MPO+, and CD68+ cells (P < or = .03) and a trend toward more CD3+ and CD4+ cells (P = .06) in their epithelium and more CD20+, kappa+ and lambda+, MPO+, and CD68+ cells (P < or = .05) and a trend toward more CD4+ cells (P = .06) in their submucosa compared with adult control subjects. Immunostains from children with positive sinus cultures were similar to those with negative cultures except for more MPO+ cells in the submucosa (P = .04). CONCLUSION The inflammatory response of young children with CRS is characterized by a mixed lymphocyte population, macrophages, and neutrophils. Differences between pediatric and adult CRS suggest differing pathogenic mechanisms or progression in the inflammatory response with protracted disease.