GVHD病因学的新视野:HLA分子三维结构研究

目的 :进一步探索GVHD的发病机理 ,提高临床移植疗效。方法 :采用国际通用的微量淋巴细胞毒试验和混合淋巴细胞培养方法 ;基因分型采用PCR SSP方法 ,对基因亚型进行DNA测序 ,再进行HLA三维结构模拟。结果 :① 4名骨髓移植患者中 ,例 1供 受体间HLA Ⅰ、Ⅱ类血清学分型相合 ,DQB1基因亚型不同 ,例 2、3、4均有 1个Ⅰ类抗原 (分别为HLA A、B和A)血清学分型不合和 1个基因亚型不同。HLA三维结构模拟例 1、3、4供 受者差别明显 ,骨髓移植后发生了Ⅲ～Ⅳ度GVHD ;例 2三维结构模拟差别不明显 ,仅发生Ⅰ度GVHD ;② 4个病例供 受体间HLA分子分别相差 14、17、2 0、12个氨基酸 ,相差数量与GVHD无相关性 ;3例重度GVHD供 受体的HLA分子三维结构均在抗原结合区的β转角处出现明显差异 ,而 1例轻度GVHD则无明显差异。 结论 :当异基因骨髓移植供 受体间HLA基因亚型不同时 ,移植后发生GVHD的程度与HLA分子三维结构差别大小有密切关系 ;三维结构的差别又与差异氨基酸所处的位置有关 ;GVHD与抗原氨基酸差别的数量多少没有直接关系。

New Prospect Opened for GVHD-initiating Etiology:Study on Three-dimentional Structure of HLA Molecules

Objective:To explore the pathogenic mechanism of GVHD and enhance the clinical therapeutic effectiveness of bone marrow transplantation(BMT).Methods:The conventional microlymphocytotoxicity test and the lymphocyte co cultivation were used.The PCR SSP was applied to genetic typing.Following the analysis of DNA sequence of sub genotype,the modeling of three dimentional structure of HLA molecules was performed.Results:①In case 1 out of the four patients with BMT,the serotyping of HLA Ⅰ and Ⅱ was matched between donor and recipient,with DQB1 sub genotype being different.However,in each of remaining case 2,3 and 4,there was one unmatched antigen of HLA Ⅰ(HLA A,B and A,respectively) between donor and recipient,with unmatched serotyping and one different sub genotype. In case 1,3 and 4,the modeling of three dimentional structure of HLA molecules had shown so distinct difference between donor and recipient that following the BMT,the GVHD of Ⅲ～Ⅳ degrees was caused. In case 2,the modeling of three dimentional structure of HLA molecules didn′ t show the distinct difference between donor and recipient so that following the BMT,the GVHD of low degree was developed.②In all four patients,the HLA molecules between donor and recipient differed from each other by 14,17,20 and 12 amino acids,respectively,and the difference in the number of amino acids had no correlation with GVHD development.The distinct difference in three dimentional structure of HLA molecules occured at β corner of antigen combining region for each of three patients with GVHD of severe degree,but there was no distinct difference in antigen combining region for case 2.Conclusion:When the gene subtypes are different between donor and recipient in allogenic BMT,the degree of GVHD development after BMT is closely correlated with the size of difference in three dimentional structure of HLA molecules,whereas the GVHD development has no direct relationship with the size of difference in the number of antigen′s amino acids.