Infiltrating leukocyte populations and T-lymphocyte subsets in head and neck squamous cell carcinomas from patients receiving perilymphatic injections of recombinant interleukin 2. A pathologic and immunophenotypic study.

Nine patients with squamous cell carcinoma of the oral cavity and oropharynx underwent preoperative perilymphatic administration of recombinant interleukin 2 (rIL-2). A more marked eosinophil and lymphocyte infiltration and more extensive edema than in 13 untreated cases were observed in surgical specimens. Necrosis was present in five of nine cases, but involved no more than 10% of the neoplastic tissue; in three of nine cases, characteristic necrotic changes with intense eosinophil infiltration possibly induced by lymphokines involved the peritumoral soft tissues. Of the tumor-infiltrating lymphocytes, T-lymphocytes (mostly CD4+ cells) prevailed over B-lymphocytes. CD4+ and CD8+ cells were mainly located close to the neoplastic sheets. Moderate amounts of CD38+ and CD11c+ cells (macrophages) and few CD16+ and CD56+ lymphocytes were found in all cases. CD25+ and LAK1+ cells were significantly more numerous in treated than in untreated cases. This suggests that local administration of rIL-2 induces an increase in activated T-lymphocyte subsets infiltrating the neoplastic tissue, thus eliciting a tumor-specific T-lymphocyte reactivity.