腎移植慢性拒絶反応の病態と治療 : 腎移植後の慢性拒絶に関連するドナー及びレシピエントの非免疫学的な危険因子

Abstract

献腎移植358腎.高齢ドナーや脳血管障害が死因であったドナーからの腎を用いた移植では, 長期的な生着率が低下していた.レシピエント側因子では, 小児において技術的な問題等で予後悪化の傾向を認めた.又, BMIの大きなレシピエントへ条件の悪いグラフトを移植した場合等では, 糸球体hyperfiltrationに伴う糸球体機能不全により長期生着率が低下していた.15年以上の長期透析例や高齢レシピエントでは急性拒絶反応の発症率が低く, 比較的長期に安定した移植腎機能が得られていた.移植腎摘出に関わる因子では, 温阻血時間が移植後の無尿期間に影響するだけでなく, 長期予後にも多大な影響を与えていた.又, 遅発性移植腎機能発現群の長期生着率は, immediate function群に比較して低下していた

Although the precise mechanisms are unclear, not only alloantigen-dependent but also antigen-independent factors are generally thought to influence the development of chronic allograft nephropathy (CAN). Among the non-immunological determinants, there are various factors related with donor, recipient and graft procurement. As donor factors, age and cause of death were demonstrated to be significantly independent in long-term graft survival of cadaveric kidney transplantation. Grafts from aged donors and from donors with athelosclerosis showed poor prognosis on graft survival. Regarding recipient factors, cardiovascular complications, as hypertension and hyperlipidemia, were responsible for graft as well as patient survival. In addition, CMV infection and drug nephrotoxicity were also shown to affect graft survival. For procurement factors, warm ischemia was determined to possess the strongest impact on long-term graft survival in our series of kidney transplant using grafts from non-heart beating donors (NHBDs). Delayed graft function, which correlated well with length of warm ischemia, also influenced long-term graft survival. These results proved that the supply of viable donor nephrons and the physiologic demands of the recipient are important determinants of long-term graft survival. So far there seems to be neither definitive nor specific treatment for CAN. It is basically essential to avoid graft damage before transplant and keep recipients from risk factors after transplant as much as possible. To improve long-term graft survival in cadaveric kidney transplantation, recipient selection is greatly important in terms of not only immunological compatibility but also body to nephron mass imbalance and ischemic time, which might cause fatal damage to grafts before engraftment.