Identified histologically by an inflammatory cell infiltrate dominated by lymphocytes and plasma cells with scant neutrophils. In its early stage, the changes are limited to the lamina propria (superficial gastritis). When the disease progresses to destroy glands, it becomes atrophic gastritis. The final stage is gastric atrophy, in which the mucosa is thin and the infiltrate sparse. Chronic gastritis can be classified based on predominant site of involvement.