Laboratory of Immunochemistry, New York Blood Center, New York, New York; Laboratory of Immunohematology and Genomics, New York Blood Center, Long Island City, New York; Rh Laboratory, Department of Pediatrics and Child Health, Faculty of Medicine, Department of Biochemistry and Medical Genetics, Faculty of Medicine, University of Manitoba, Winnipeg, Manitoba, Canada; Japanese Red Cross Hokkaido Block Blood Center, Sapporo, Japan; Japanese Red Cross Kinki Block Blood Center, Ibaraki, Japan.
Transfusion. 2013 Nov;53(11):2710-4. doi: 10.1111/trf.12118. Epub 2013 Feb 25.
The ABCG2 gene encodes antigens of the JR blood group system. Red blood cells (RBCs) from individuals homozygous for ABCG2 null alleles are nonreactive with polyclonal and monoclonal anti-Jr(a) . However, some RBCs have been defined as Jr(a+(W) /-) or Jr(a-), particularly when tested with polyclonal anti-Jr(a) . In an effort to resolve these apparent serologic ambiguities, the current study was undertaken.
Hemagglutination of RBCs from two individuals known to express a single copy of functional ABCG2 were compared to RBCs from eight unrelated, previously characterized, Jr(a+(W) /-) donors. Standard polymerase chain reaction-based methods were used to characterize ABCG2 alleles.
Two monoclonal anti-Jr(a) clones agglutinated RBCs from the eight Jr(a+(W) /-) study subjects. Two of these subjects were homozygous for a missense ABCG2 change (c.1858A; Asp620Asn). Two were heterozygous for two missense changes; one was c.1858G>A and c.421C>A (Asp620Asn; Gln141Lys), and the other was c.1714A>C and c.421C>A (Ser572Arg; Gln141Lys). The remaining four subjects were heterozygous for c.421C>A (Gln141Lys), and for one of four null alleles.
We have identified three ABCG2 alleles that are newly associated with weakened Jr(a) expression. One of these is novel, the missense allele c.1714A>C (Ser572Arg) and two that have been previously described c.421C>A (rs2231142; Gln141Lys) and c.1858G>A (rs34783571; Asp620Asn). In addition, we found a novel, presumed null allele, c.1017_1019delCTC (Ser340del).
ABCG2 基因编码 JR 血型系统的抗原。ABCG2 缺失等位基因纯合子个体的红细胞（RBC）与多克隆和单克隆抗-Jr(a) 不反应。然而，一些 RBC 被定义为 Jr(a+(W) /-) 或 Jr(a)-，特别是用多克隆抗-Jr(a) 检测时。为了解决这些明显的血清学歧义，进行了当前的研究。
比较已知表达单个功能性 ABCG2 拷贝的两个人的 RBC 凝集与来自八个无关的、先前表征的 Jr(a+(W) /-) 供体的 RBC。使用标准聚合酶链反应（PCR）方法来表征 ABCG2 等位基因。
两个单克隆抗-Jr(a) 克隆凝集了来自八个 Jr(a+(W) /-) 研究对象的 RBC。这两个对象都是错义 ABCG2 变化（c.1858A；Asp620Asn）的纯合子。两个是两个错义变化的杂合子；一个是 c.1858G>A 和 c.421C>A（Asp620Asn；Gln141Lys），另一个是 c.1714A>C 和 c.421C>A（Ser572Arg；Gln141Lys）。其余四个对象是 c.421C>A（Gln141Lys）和四个无功能等位基因之一的杂合子。
我们已经确定了三个与 Jr(a) 表达减弱新相关的 ABCG2 等位基因。其中一个是新的错义等位基因 c.1714A>C（Ser572Arg），另外两个是以前描述过的 c.421C>A（rs2231142；Gln141Lys）和 c.1858G>A（rs34783571；Asp620Asn）。此外，我们发现了一个新的、推测为无功能的等位基因 c.1017_1019delCTC（Ser340del）。
