Inflammatory cells in Helicobacter pylori-associated gastritis (HAG) were quantified. The results were compared with the gastric biopsy samples from patients with non-Helicobacter pylori gastritis (non-HAG). In order to detect immunocytochemically sensitive antigens, the biopsy samples were acetone-fixed at -20 degrees C and processed into glycol methacrylate at 4 degrees C. Parallel routine biopsy samples were formalin-fixed and paraffin-embedded. A larger, more selective retrospective study was also established examining routinely processed gastric biopsy samples. The results of both studies were expressed as numbers of individual cell types/mm2 of gastric mucosa, and showed that neutrophil granulocytes were significantly increased in HAG whereas T-lymphocytes were not. Heli. pylori colonisation was associated with a significant increase of CD8-positive lymphocytes in the epithelium of the crypts.