Transgenerational Microchimerism in Pregnancy Loss

描述（由申请人提供）：微嵌合（Mc）是指从遗传上不同的个体中容纳少量细胞或DNA。在怀孕期间，Mc是在母亲和胎儿之间的细胞交换中自然获得的。在之前的研究中，我们发现母亲的细胞在她的后代成年后仍然存在。在怀孕期间，已经从母亲那里获得Mc宿主的妇女获得了额外的Mc来源，因为来自母体的细胞和无细胞DNA进入了她的血液循环。这些观察结果提出了一个问题，即hla代际关系是否会影响女性妊娠的结果，以及由于遗传多样性通常被认为是良好的，过多的hla代际共享是否会导致复发性特发性妊娠丢失（RPL）。HLA分子是免疫反应的核心，区分自我与“他人”和广泛的多态性是HLA基因的标志性特征。由于HLA基因的多态性，在大多数情况下，HLA等位基因在家庭成员之间存在许多差异。然而，由于hla -纯合性或hla -杂合性的同一性，偶尔会在家族中观察到hla共享的增加。先前的研究表明，女性及其伴侣的过多hla共享与特发性RPL有关，尽管研究结果相互矛盾。本R21提案的第一个具体目标将检验以下假设：与活产且无流产史的先证者相比，当女性先证者患有原发性特发性RPL时，三代人的hla关系差异较小（增加共享）。将对原发性特发性RPL妇女及其母亲、孕妇和伴侣进行DRB1、DRB3、DRB4、DRB5、DQA1、DQB1、A、B和C的hla基因分型。特异性目标2将在患有原发性特发性RPL并随后流产或活产的先证者和无流产史的健康妇女的妊娠前、妊娠期间和妊娠后的连续血液样本中鉴定和量化先证者母亲的Mc （MP-Mc）。为此目的，一组hla特异性和其他基因多态性特异性定量PCR检测已经开发出来，并将用于检测外周血单个核细胞。特异性Aim 3将从先证者（CP-Mc）的概念出发，在相同的外周血样本中使用与Aim 2相同的方法来检测外周血单个核细胞和血清中的Mc。除了目标1的假设之外，第二个假设将在目标2和目标3中进行验证，即Mc的动态变化，无论是MP-Mc还是CP-Mc，或两者兼而有之，都与特发性RPL有关。从多种来源携带Mc的后果和长期影响在很大程度上是未知的，因为从怀孕中自然获得的Mc直到最近才被认识到。据我们所知，在特发性RPL中，没有先前的研究调查hla共享或Mc跨代。含有少量来自基因不同个体的细胞（或DNA）被称为微嵌合（Mc）。女性从自己的母亲那里携带mcc，后来又从自己的怀孕中获得mcc，这一发现提出了一个问题，即跨代细胞群之间的相互作用是否有时会影响怀孕成功。因为它们有助于区分一个细胞与另一个特定的基因，称为HLA基因，是特别感兴趣的研究。

DESCRIPTION (provided by applicant): Microchimerism (Mc) refers to harboring a small number of cells or DNA from a genetically distinct individual. During pregnancy Mc is naturally acquired in the exchange of cells between a mother and conceptus. In prior studies we found that a mother's cells persist in her progeny into adult life. During pregnancy a woman who is already host to Mc from her mother acquires an additional source of Mc as cells and cell-free DNA from the conceptus enter her circulation. These observations raise the question of whether HLA-relationships across generations influence the outcome of pregnancy in women and, as genetic diversity is generally thought to be good, whether excessive HLA-sharing across generations contributes to recurrent idiopathic pregnancy loss (RPL). HLA molecules are central to immune responses, to distinguishing self from "other" and extensive polymorphism is the hallmark feature of HLA genes. Due to the polymorphism in HLA genes most of the time there are numerous differences in HLA alleles among family members. However, occasionally an increase of HLA-sharing is observed in families, either due to HLA-homozygosity or heterozygous HLA-identity. Previous studies have suggested that excessive HLA-sharing of a woman and her partner is associated with idiopathic RPL, although studies have been conflicting. The first Specific Aim of this R21 proposal will test the hypothesis that HLA-relationships over three generations have less HLA-disparity (increased sharing) when women probands have primary idiopathic RPL compared to probands with a live birth and no history of miscarriage. HLA-genotyping will be conducted for DRB1, DRB3, DRB4, DRB5, DQA1, DQB1, A, B and C for women with primary idiopathic RPL, their mothers, conceptus, and partners. Specific Aim 2 will identify and quantify Mc from the proband's mother (MP-Mc) in consecutive blood samples from before, during and after pregnancy for probands with primary idiopathic RPL with a subsequent miscarriage or with a live birth and healthy women with no history of miscarriage. For this purpose a panel of HLA-specific and other genetic polymorphism specific quantitative PCR assays has been developed and will be employed to tested peripheral blood mononuclear cells. Specific Aim 3 will quantify Mc from the conceptus of the proband (CP-Mc) in the same peripheral blood samples using the same methods as in Aim 2 to test peripheral blood mononuclear cells as well as serum. In addition to the hypothesis of Aim 1, a second hypothesis will be tested in Aims 2 and 3, that dynamic changes in Mc, either MP-Mc or CP-Mc or both, is associated with idiopathic RPL. The consequences and long-term effects of harboring Mc from multiple sources are largely unknown as naturally acquired Mc from pregnancy has only recently been recognized. To our knowledge there are no prior studies investigating HLA-sharing or Mc across generations in idiopathic RPL. Harboring a small number of cells (or DNA) that originated from a genetically distinct individual is referred to as microchimerism (Mc). The finding that women harbor Mc from their own mothers and later acquire Mc from their own pregnancy(ies) raises questions about whether interactions between cell populations across generations sometimes influences pregnancy success. Because they help distinguish one cell from another particular genes, called HLA genes, are of special interest to investigate.