Fig. 2

Morphological examination of oropharynx biopsies showed marked lymphocytic inflammation of the submucosa (a, original magnification × 40) with infiltration of the epithelial layer, where scattered apoptotic cells were observed (b, original magnification × 200). Immunohistochemical staining revealed that a minor population of lymphocytes (about 10%) was CD20 positive (c, original magnification × 100), while the majority of lymphocytic infiltration (about 90%) was represented by CD3-positive T-cells (d, original magnification × 100). Among T-lymphocytes, about 80% were CD4 positive (e, original magnification × 100) and about 20% were CD8 positive (f, original magnification × 100)