Tavares Letícia, Da Costa Daiane Cobianchi, Batschauer Anna Paula de Borba, Jobim Luiz Fernando Job, Ewald Gisele Menezes, de Mello Carolina, Velazquez Eduardo Samuel Alvarez, Geraldo Alexandre
University of Vale do Itajaí, Itajaí, Brazil.
University of Vale do Itajaí, and Chief Technician, Batschauer Laboratory LTDA, Itajaí, Brazil.
Immunohematology. 2018 Dec;34(4):151-157.
Chimerism is a phenomenon in which an individual has cells with different genetic content from different zygotes. In dizygotic twins (DTs), chimerism is believed to occur through placental anastomoses that enable the bidirectional exchange of hematopoietic stem cells. Little is still known about chimerism frequency in twins, but several studies have shown a relation between chimerism and some conditions such as autism, Alzheimer's disease, and a group of autoimmune diseases such as Sjögren syndrome, systemic lupus erythematosus, and systemic sclerosis. In addition to chimerism of ABO blood groups being possibly mistaken for ABO subgroups, these autoimmune diseases may affect other serologic immunohematologic tests. This study aimed to determine the frequency of chimerism in DTs through ABO and D testing using the tube method, column agglutination, and short tandem repeat (STR) assays. Among the 103 subjects assessed for this study, 24 subjects (12 pairs) were excluded because STR assays showed they were monozygotic; of the remaining, 70 subjects (35 pairs) were DTs and 9 subjects came from gestations of trizygotic triplets. No ABO or D chimerism was detected in any subject through serologic assays, and STR assays did not detect any blood chimerism. Although there was no evidence of chimerism found in this study, we emphasize the importance of observing the family background of individuals with suspected ABO subgroup in complex immunohematologic studies because ABO antigen-antibody reactions are similar in both circumstances, and chimerism can be overlooked. Moreover, the use of the STR analysis method in chimerism studies can be important to help differentiate chimerism and ABO subgroups.
嵌合体是一种个体具有来自不同受精卵的不同遗传物质的细胞的现象。在异卵双胞胎（DTs）中，嵌合体被认为是通过胎盘吻合发生的，胎盘吻合使造血干细胞能够双向交换。关于双胞胎中嵌合体的频率仍知之甚少，但一些研究表明嵌合体与某些疾病有关，如自闭症、阿尔茨海默病以及一组自身免疫性疾病，如干燥综合征、系统性红斑狼疮和系统性硬化症。除了ABO血型嵌合体可能被误认为ABO亚型外，这些自身免疫性疾病可能会影响其他血清学免疫血液学检测。本研究旨在通过使用试管法、柱凝集法和短串联重复序列（STR）分析进行ABO和D检测来确定DTs中嵌合体的频率。在本研究评估的103名受试者中，有24名受试者（12对）因STR分析显示为单卵双胞胎而被排除；其余的70名受试者（35对）为DTs，9名受试者来自三卵三胞胎妊娠。通过血清学检测在任何受试者中均未检测到ABO或D嵌合体，STR分析也未检测到任何血液嵌合体。尽管本研究中没有发现嵌合体的证据，但我们强调在复杂的免疫血液学研究中观察疑似ABO亚型个体的家族背景的重要性，因为在这两种情况下ABO抗原 - 抗体反应相似，嵌合体可能会被忽视。此外，在嵌合体研究中使用STR分析方法对于帮助区分嵌合体和ABO亚型可能很重要。
