Sell K W, Tadros T, Wang Y C, Hertzler G, Knopf W D, Murphy D A, Ahmed-Ansari A
Department of Pathology & Laboratory Medicine, Emory University School of Medicine, Atlanta, Georgia 30322.
J Heart Transplant. 1988 Nov-Dec;7(6):407-18.
Our previous data indicate that normal human cardiac myocytes do not express detectable levels of major histocompatibility complex (MHC) class II gene products and express only low levels of MHC class I gene products. Examination of heart biopsy samples after transplantation with immunoperoxidase techniques revealed that such myocytes are induced to express high levels of MHC class I/II gene products and that the expression of these gene products appeared to precede histologic evidence of rejection. In efforts to objectively quantitate the level of MHC antigen expression on sequential heart biopsy samples, a radioimmunoassay was set up. Monoclonal antisera was used against human monomorphic MHC class I and II determinants. In addition, to control for the variability in the quantity of biopsy sample, use was made of a monoclonal antisera against human cardiac myosin. A series of three to four sections (4 micron each) of the heart biopsy specimen was treated with each antisera, followed by affinity purified and absorbed iodine 125-labeled goat antimouse immunoglobulin. The mean counts per minute of MHC class I and II was divided by the mean counts per minute obtained with anti-myosin and an index of MHC class I/II derived. Data using such a radioimmunoassay indicate that MHC antigen expression on the heart biopsy specimens does not strictly correlate with histologic rejection grade scores, levels of leukocyte infiltrate, or the immunophenotype of the infiltrating mononuclear cells. Of interest was the finding that an increase in the level of MHC antigen expression occurred before histologic evidence of rejection grades of 3 or greater. In addition, MHC class I antigen expression appeared to increase in heart biopsy samples early during the post-transplant period, followed sequentially by an increase in the level of MHC class II antigen expression. Rejection episodes later during the posttransplant period, however, were accompanied by increased levels of MHC class II antigens. A kinetic analysis of the increase in the levels of MHC class I and II antigens on heart biopsy samples may not only provide a refinement of the histologic scoring of heart biopsy samples for rejection but may also suggest the use of different chemotherapeutic immunosuppressive drug regimens for the treatment of MHC class I as compared with MHC class II dependent rejection episodes.
我们先前的数据表明，正常人类心肌细胞不表达可检测水平的主要组织相容性复合体（MHC）II类基因产物，仅表达低水平的MHC I类基因产物。采用免疫过氧化物酶技术对移植后的心脏活检样本进行检查发现，此类心肌细胞被诱导表达高水平的MHC I/II类基因产物，且这些基因产物的表达似乎先于排斥反应的组织学证据出现。为了客观定量连续心脏活检样本上MHC抗原的表达水平，建立了一种放射免疫测定法。使用针对人单态MHC I类和II类决定簇的单克隆抗血清。此外，为控制活检样本数量的变异性，使用了针对人心肌肌球蛋白的单克隆抗血清。心脏活检标本的一系列三到四个切片（每个4微米）用每种抗血清处理，随后用亲和纯化并吸附了碘125标记的山羊抗小鼠免疫球蛋白处理。将MHC I类和II类的每分钟平均计数除以抗肌球蛋白获得的每分钟平均计数，得出MHC I/II类指数。使用这种放射免疫测定法得到的数据表明，心脏活检标本上的MHC抗原表达与组织学排斥分级评分、白细胞浸润水平或浸润单核细胞的免疫表型并不严格相关。有趣的是，发现MHC抗原表达水平在排斥分级达到3级或更高的组织学证据出现之前就有所增加。此外，MHC I类抗原表达在移植后早期的心脏活检样本中似乎有所增加，随后MHC II类抗原表达水平依次增加。然而，移植后期的排斥发作伴随着MHC II类抗原水平的升高。对心脏活检样本上MHC I类和II类抗原水平升高进行动力学分析，不仅可以完善心脏活检样本排斥反应的组织学评分，还可能提示针对MHC I类依赖性排斥发作与MHC II类依赖性排斥发作，应使用不同的化疗免疫抑制药物方案进行治疗。
