5) 免疫不全―移植片対宿主病（graft-versus-host disease；GVHD），後天性免疫不全症候群（acquired immunodeficiency syndrome；AIDS）

Clinical and Endoscopic Features of Small Intestinal Lesions in Graft-versus-host Disease (GVHD) and Acquired Immunodeficiency Syndrome (AIDS)

要旨　代表的な免疫不全状態である移植片対宿主病(graft-versus-host disease;GVHD)および後天性免疫不全症候群(acquired immunodeficiency syndrome; AIDS)の小腸病変について概説した．GVHDは下痢を主症状とし発症し，下部消化管の中では終末回腸が好発部位である．終末回腸の内視鏡像は浮腫，発赤，潰瘍の頻度が高いがこれらの所見はGVHDに特異的な所見ではない．びまん性の広範囲な粘膜脱落はGVHDに特徴的で他の疾患ではみられない．病理組織では腺窩上皮のアポトーシスが特徴的である．AIDSでは小腸に日和見感染症および腫瘍性病変を生じる．感染症ではサイトメガロウイルスの感染の頻度が高く，そのほか原虫，寄生虫感染もみられる．腫瘍性病変としてはカポジ肉腫が重要である．免疫不全状態では小腸病変が予後に影響すると考えられ，その内視鏡像，病理像の理解が重要と思われる．

　We reviewed clinical and endoscopic findings of small intestinal lesions in graft-versus-host disease (GVHD) and acquired immunodeficiency syndrome (AIDS). Acute GVHD involving the small intestine characteristically manifests as secretory diarrhea. The terminal ileum is most vulnerable to GVHD. Erythema, mucosal edema and ulcers are more frequent endoscopic findings of GVHD in the terminal ileum. However, these findings are not specific to GVHD. On the other hand, diffuse sloughing of the mucosa is infrequent but highly specific to GVHD. Histologically, the presence of apoptosis of the glandular epithelium is characteristic in GVHD. This histological finding is seen regardless of apparent endoscopic lesions.

　Chronic diarrhea is common in patients with clinically apparent AIDS. In AIDS, chronic diarrhea is caused by opportunistic infections with protozoa, parasite, bacteria and viruses. The intestinal neoplasm occurs in patients with AIDS. Kaposi's sarcoma is the most frequent malignant tumor in the intestine. Kaposi's sarcoma appears as a reddish submucosal tumor.

　The comprehension of the endoscopic and the pathological findings of intestinal lesions is important in the management of patients with GVHD and AIDS, because these lesions influence the clinical course and the prognosis of patients.