Ferguson S J, Blajchman M A, Guzewski H, Taylor C R, Moulds J
Vox Sang. 1982;43(2):82-6.
Animals genetically capable of making certain gene products have been shown to have the production of such products completely or partially suppressed by exposure in utero or neonatally to antibodies specific for that gene product. This alloantibody-induced depression of expression of a specific antigenic determinant has yet to be shown to occur in man. The McCoya red blood cell antigen is reported to be well developed at birth. However, 2 children born to mothers with high-titer McCoya antibodies in their serum, phenotyped as McCoy (a-) at birth and, on retesting their red blood cells, 1 at 5 months and the 2nd at 11 months, both phenotyped as McCoy (a+). It is possible that this lack of expression of the McCoya antigen at birth represents a characteristic of an obligate heterozygote. However, on testing 50 random umbilical cord red blood cell samples with two potent McCoya antisera, only 1 was found to be negative. If the negative phenotype were a characteristic of an obligate heterozygote at birth, then the neonatal incidence of the McCoy (a-) phenotype should have been significantly (p less than 10(-4)) high in our random cord blood sample than observed (expected 11). The impaired expression of the McCoya antigen on the red blood cells of these 2 infants at birth, in conjunction with evidence of maternal alloimmunization, strongly suggests alloantibody-induced antigenic suppression of the McCoya antigen as a probable cause.
基因上能够产生某些基因产物的动物已被证明，在子宫内或新生儿期接触针对该基因产物的特异性抗体后，其此类产物的产生会被完全或部分抑制。这种同种抗体诱导的特定抗原决定簇表达的抑制在人类中尚未得到证实。据报道，麦科伊红细胞抗原在出生时就已充分发育。然而，有2名母亲血清中含有高效价麦科伊抗体的儿童，出生时表型为麦科伊（a-），在对其红细胞进行重新检测时，1名在5个月时、另1名在11个月时，两者表型均为麦科伊（a+）。出生时麦科伊抗原的这种表达缺失可能代表了纯合子的一种特征。然而，在用两种高效价麦科伊抗血清检测50份随机脐带血红细胞样本时，仅发现1份为阴性。如果阴性表型是出生时纯合子的一种特征，那么在我们的随机脐带血样本中，麦科伊（a-）表型的新生儿发病率应该显著高于观察到的（预期为11例）（p小于10-4）。这2名婴儿出生时红细胞上麦科伊抗原的表达受损，再加上母体同种免疫的证据，强烈提示同种抗体诱导的麦科伊抗原的抗原抑制是一个可能的原因。
