消化管T細胞性リンパ腫の診断と治療

Diagnosis and Treatment of Intestinal T-cell Lymphoma

腸管症型T細胞リンパ腫（EATL）は，腸管上皮内Tリンパ球を発生起源とする特徴的な疾患群で，空腸と回腸が好発部位である．消化管穿孔を契機に診断されることも多く，その予後は極めて不良とされていたが，近年，バルーン内視鏡やカプセル内視鏡を用いた早期診断例も報告されている．今後，これらのモダリティーを用いた早期診断が，予後改善の鍵になると思われる．成人T細胞性白血病/リンパ腫（ATL/L）は，消化管原発例が少なく，大部分が全身疾患としての消化管病変であり，多彩な形態の病変を形成する．ATL/Lは，通常の化学療法に抵抗性で予後不良であったが，近年，同種造血幹細胞移植が長期生存を期待できる治療法として推奨され，ヒト化抗CCR4抗体の有効性も期待されている．

　EATL（enteropathy-associated T-cell lymphoma）is a primary extranodal T-cell lymphoma arising in the intestine and originating from intraepithelial T cells. EATL most commonly arises in the jejunum or ileum. Approximately 40% of patients seek care because of acute abdominal pain owing to intestinal obstruction and/or perforation by a tumor, with acute peritonitis requiring an emergency surgical procedure. Septicemia due to acute peritonitis accounts for the dismal prognosis in these cases.

　Recently, some cases of EATL were reported, where the disease was diagnosed early using an endoscopic modality, such as double-balloon enteroscopy and/or capsule endoscopy. For optimal treatment of EATL, it is important to diagnose the disease at an early stage, using these endoscopic modalities.

　Systemic ATL/L（adult T-cell leukemia/lymphoma）, which is caused by HTLV-1（human T-lymphotropic virus type 1）, often involves the gastrointestinal tract, but primary gastrointestinal T-cell lymphoma associated with HTLV-1 is rare. Systemic ATL/L leads to various lesions in the gastrointestinal tract.

　Patients with acute or lymphomatous ATL/L have extremely poor prognosis, mainly because of resistance to conventional chemotherapies. Recently, allogeneic HSCT（hematopoietic stem cell transplantation）and a humanized anti-CCR4 monoclonal antibody were tested as a promising alternative that can provide long-term remission in a proportion of patients with ATL/L.