morpho⊥ogy 1.inflammatory changes limit to the upper 1/3 of the mucosa 2. a lymphocytic and plasma cell infiltrate in the upper mucosa 3. swelling degeneration and necrosis of the superficial mucosal epitheliummorphology ⒈inflammatory changes limit to the upper 1／3 of the mucosa； ⒉ a lymphocytic and plasma cell infiltrate in the upper mucosa； ⒊swelling 、degeneration and necrosis of the superficial mucosal epithelium