Ward F E, MacQueen J M
Transplant Laboratory, Durham Veterans Affairs Medical Center, North Carolina, USA.
Clin Transplant. 1996 Dec;10(6 Pt 2):620-4.
In the United States, allocation of cadaveric kidneys is federally regulated and based on the concept of equal access to all patients, regardless of race, sex, age, or socioeconomic status. Nevertheless, it has been widely reported that African American patients with renal disease wait longer for kidney transplantation and, once transplanted, have poorer graft survival. We have assessed immunogenetic factors that may contribute to ethnic differences in allograft survival by examining the distributions of ABO blood groups, HLA antigens and haplotypes, percent reactive antibody (PRA), age, and gender in our local patient population. Approximately 62% of patients at our transplant center waiting for renal transplantation are African American; 39% are female. Age distribution is comparable to that reported nationally. ABO blood groups of patients on the waiting list are distributed similarly to those reported nationally for other renal patients. Sensitization to HLA antigens, through either blood transfusion, prior transplant, or pregnancy, has been strongly associated with poorer graft survival. Although, as expected, distribution of PRA was significantly different for males versus females at one time point, it did not differ between ethnic groups in our patient population. HLA polymorphism was assessed by comparisons of HLA allele and haplotype frequencies determined by analyses of African American and Caucasian families typed in our program since 1991. Haplotypes observed in each ethnic population were subjected to a variety of statistical analyses. Coefficient of contingency and Cramer's V statistic (measures of degree of association) were consistently higher for Caucasian haplotypes than for those of African Americans. Significantly more unique HLA haplotypes were observed among African American families than among Caucasian families. Thus, our data provide evidence for greater HLA linkage disequilibrium in Caucasians than in African Americans. HLA antigen and haplotype polymorphisms are likely, therefore, to be major immunogenetic factors contributing to ethnic differences in renal allograft survival.
在美国，尸体肾的分配由联邦政府监管，基于所有患者都能平等获得的理念，无论种族、性别、年龄或社会经济地位如何。然而，有广泛报道称，患有肾病的非裔美国患者等待肾脏移植的时间更长，而且一旦接受移植，移植肾的存活情况更差。我们通过检查当地患者群体中ABO血型、HLA抗原和单倍型、反应性抗体百分比（PRA）、年龄和性别的分布情况，评估了可能导致同种异体移植存活存在种族差异的免疫遗传因素。我们移植中心等待肾移植的患者中约62%是非裔美国人；39%是女性。年龄分布与全国报告的情况相当。等待名单上患者的ABO血型分布与全国报告的其他肾病患者相似。通过输血、既往移植或妊娠对HLA抗原致敏，与较差的移植肾存活密切相关。尽管正如预期的那样，在一个时间点上男性和女性的PRA分布存在显著差异，但在我们的患者群体中不同种族之间并无差异。自1991年以来，我们通过对参与我们项目的非裔美国家庭和白种人家庭进行分析，比较所确定的HLA等位基因和单倍型频率，来评估HLA多态性。对每个种族群体中观察到的单倍型进行了各种统计分析。白种人的单倍型的列联系数和克莱默V统计量（关联程度的度量）始终高于非裔美国人的。在非裔美国家庭中观察到的独特HLA单倍型明显多于白种人家庭。因此，我们的数据为白种人比非裔美国人存在更大的HLA连锁不平衡提供了证据。因此，HLA抗原和单倍型多态性可能是导致肾同种异体移植存活存在种族差异 的主要免疫遗传因素。
