NHPHの病理組織学的所見

Histopathology of Gastric Non-Helicobacter pylori Helicobacters and Associated Gastritis

要旨●胃に棲息するNHPH（Non-Helicobacter pylori Helicobacter）は慢性胃炎や胃・十二指腸潰瘍，胃MALTリンパ腫の発症に関わっている．NHPHは大型の桿菌で，corkscrew型の螺旋構造を持ち，H. pyloriとの鑑別にはGiemsa染色が有効である．また，抗H. pylori抗体を用いた免疫組織化学染色もNHPHの検索に有効である．NHPHは幽門部の感染頻度が高く，胃上皮細胞への接着を欠き，胃小窩内や胃粘膜表面の粘液ゲル層内に観察され，壁細胞内に認められることもある．NHPH感染慢性胃炎の特徴としては，幽門部優位の胃炎，胃上皮傷害像の欠如，軽度〜中等度の単核細胞浸潤，軽微な好中球浸潤，大型リンパ濾胞，胃小窩内のリンパ球の小集塊，腸上皮化生がまれである点が挙げられる．

　NHPH（Non-Helicobacter pylori Helicobacters）infect the human gastric mucosa and are associated with gastritis, gastroduodenal ulcers, and gastric mucosa-associated lymphoid tissue lymphoma. NHPH are “tightly spiral shaped bacteria（corkscrew shape）” and have a predominantly straight appearance with large size of 4−10μM. They are readily distinguished from H. pylori（Helicobacter pylori）in Giemsa-stained sections. Immunostaining with anti- H. pylori antibodies also often reveal reactivity with NHPH. The gastric antrum is predominantly colonized by NHPH found in the mucous gel, both in the gastric foveolar lumen and on the mucosal surface, without adhesion to epithelial cells. Further, they are sometimes observed within the parietal cells. The distinctive histologic features of NHPH-associated chronic gastritis are as follows：antrum-predominant gastritis, absence of epithelial damage, mild-to-moderate mononuclear infiltration, slight and focal neutrophil infiltration, lymphocyte exudation into gastric foveolae, sizable lymphoid follicle with a germinal center, and infrequent intestinal metaplasia.