免疫異常の病態と消化管病変

Pathogenesis of Immunodeficiency Disorders and Gastrointestinal Lesions

要旨　消化管に病変を来す原発性免疫不全症（PID）はCVID，XLA，IgA欠損症，SCID，Wiskott-Aldrich症候群，ataxia-telangiectasia，慢性肉芽腫症，Chediak-Higashi症候群，無汗性外胚葉形成不全症，高IgE症候群などが挙げられる．これら疾患にみられる消化管病変としては消化管感染症，スプルー様病変，潰瘍を伴う多彩な炎症性変化，自己免疫病変（IBD，PA），消化管の悪性腫瘍（癌，リンパ腫）がある．これら病変の多くは病変成立機序に反復・遷延する重篤な感染が重要な役割を果たしていると考えられる．続発性免疫不全症の原因疾患としてはAIDS，ATL/L，GvHD，膠原病，α鎖病，医原性要因などが挙げられる．これら疾患にみられる消化管病変は，種々の寄生虫やウイルスを中心とした日和見感染，組織のapoptosis，Kaposi肉腫，原発腫瘍の消化管浸潤などがある．既存のカテゴリーにあてはまらない消化管病変に遭遇した場合，患者の全身徴候に注意を払い，免疫学的検索を行うことが必要である．

　Primary immunodeficiency disorders (PID) which demonstrate organic lesions in the digestive tracts are CVID, XLA, IgA deficiency, SCID, Wiscott-Aldrich syndrome, Ataxia-Telangiectasia, Chronic granulomatous disease, Chediak-Higashi syndrome,Anhidrotic Ectodermal Dysplasia and Hyper IgE syndrome. Various gastrointestinal (GI) lesions in PID which have been reported are GI infections, sprue-like disorder, various inflammatory lesions including ulcers, autoimmune disorders (IBD, PA) and GI tumors (cancer, lymphoma). The morphology of most these lesions might be mainly influenced by repeated and prolonged severe GI infection. Causal diseases of secondary immunodeficiency disorders are AIDS, ATL/L, GvHD, collagen disease, α-chain disease and iatrogenic factors (immunosuppressive agents, radiation, anticancer drug etc.) The GI lesions of secondary immunodeficiency disorders are due to opportunitic infection of parasites and virus, apoptosis of tissues, Kaposi sarcoma and infiltration of the GI mucosa by primary tumors.

　It is necessary to examine a patient carefully and undertake an immunological evaluation of the patient when lesions with unusual morphology have seen.