寻找HLA匹配无关供者概率曲线的计算及其应用

目的　建立在骨髓库中寻找到HLA匹配供者概率曲线P的回归方程式 ,并用于评估骨髓库的最适大小。方法　在哈迪 -温伯格群体中的HLA单体型频率可以从供者表型资料求得。寻找到一个HLA匹配供者的概率可以表示成供者数和HLA单体型频率的函数。使用对数曲线拟合方法推导出该概率曲线的回归方程。结果　笔者推导出在中国人骨髓库中寻找到至少一例HLA -A ,B ,DR抗原全配合供者概率的回归方程式为P =- 0 .6 7+0 .2 5lgN(N为骨髓库中的供者数 ,介于 5万到 1 0 0万 )。在骨髓库供者数达到 75万人时 ,大约 80 %的患者可以找到HLA配合供者。结论　找到HLA配合供者概率取决于骨髓库供者人数的多寡以及HLA单体型频率。HLA群体遗传学资料有助于决定骨髓库的最适大小及其供者成员的组成。

The formula for estimating the probability of finding HLA-matched unrelated marrow donor and its application

Objective Establishment of a simple mathematic method to estimate the probability (P) of finding a HLA antigen matched unrelated donor for hematopoietic stem cell transplantation and determine the optimal size of unrelated donor pool.Methods Assuming a Hardy Weinberg equilibrium of underlying population,HLA haplotype frequencies were estimated from phenotype data in the donor pool.The curve of P value was established on the basis of HLA haplotype frequency.Logarithmic curve fitting method was used to derive a regression equation to calculate P value.Results The formula of P=-0.67+0.25lgN was provided by the author to roughly estimate the probability of finding an HLA A,B,DR antigen matched unrelated Chinese donor.N is the number of donors in the pool and between 50 000 to a million.Approximately 80% patients could find a matched donor at HLA antigen level in a pool of 750 000 donors.Conclusion The probability of finding HLA matched donor depends on the pool size and HLA haplotype frequencies.HLA population genetics data could be used to evaluate optimal pool size and composition.