Watson R M, Scheel J N, Petri M, Kan J S, Provost T T, Ratrie H, Callan N A
Department of Dermatology, Johns Hopkins Medical Institutions, Baltimore, MD 21205.
Br J Dermatol. 1994 Mar;130(3):342-8. doi: 10.1111/j.1365-2133.1994.tb02931.x.
Autoantibody, HLA studies and C4 phenotypes were performed on twins discordant for isolated congenital heart block. Serum from the mother and cord blood from the infants revealed Ro(SSA) and La(SSB) antibodies in all three sera. No significant difference in Ro(SSA) antibody titre was noted in the cord blood of either twin when compared with maternal titres, as detected by a sensitive ELISA assay. The infants' mother was HLA-DR3 positive. Both infants had identical HLA and C4 phenotypes. Immunoblot analysis revealed that sera from both mother and infants reacted with the 52-kDa Ro(SSA) macromolecule. Quantitative cord blood IgM levels were not elevated in either twin. This study indicates that placental transfer of anti-Ro(SSA) or anti-La(SSB) alone to the fetus is not sufficient for the expression of congenital complete heart block. We conclude from this experiment of Nature that there must be a second event determining which infant develops complete heart block, but this is unknown at present.
对患孤立性先天性心脏传导阻滞的异卵双胞胎进行了自身抗体、人类白细胞抗原（HLA）研究及补体C4表型分析。母亲的血清和婴儿的脐带血显示，三份血清中均存在Ro（SSA）和La（SSB）抗体。通过灵敏的酶联免疫吸附测定法（ELISA）检测发现，与母亲的抗体滴度相比，双胞胎脐带血中Ro（SSA）抗体滴度无显著差异。婴儿的母亲HLA - DR3呈阳性。两个婴儿具有相同的HLA和C4表型。免疫印迹分析显示，母亲和婴儿的血清均与52-kDa的Ro（SSA）大分子发生反应。两个双胞胎的脐带血IgM定量水平均未升高。该研究表明，仅抗Ro（SSA）或抗La（SSB）经胎盘转移至胎儿并不足以导致先天性完全性心脏传导阻滞的发生。基于这一自然实验我们得出结论，必定存在另一个事件决定哪个婴儿会发展为完全性心脏传导阻滞，但目前这一事件尚不清楚。
