Analysis of trans-placental HIV infection

最近在艾滋病毒感染母亲的围产期护理方面取得的进展使日本的垂直传播率低至2%。然而，经胎盘感染HIV的机制仍然是一个谜和不可控的。在这项研究中，我们描述了HIV感染母亲的胎盘病理，以检查先天性HIV感染的病理生理学和可能的胎盘屏障的形态学基础。对象与方法日本艾滋病工作组采集了12例HIV感染母亲的胎盘标本。所有病例均在分娩前行择期剖宫产。12例患者中11例接受口服AZT治疗。分娩的新生儿没有出现先天性感染的迹象。采用HE染色、TUNEL及免疫组织化学检测胎盘。用抗EGF-R、erbb - b2和CD11b包被的MACS分别识别绒毛滋养层细胞（VT）、外膜滋养层细胞（EVT）和霍夫鲍尔细胞（Hob），分离胎盘细胞的各种成分。RT-PCR检测HIVgp120 RNA的存在。结果通过常规组织学检查，我们观察到HIV感染者胎盘间肠炎和细胞凋亡的发生率增加。TUNEL染色定量分析细胞凋亡评分增加。免疫组化染色显示12个胎盘中2个存在HIV p24抗原。P24定位于VT和Hob。利用抗原分离的胎盘细胞，我们在VT、EVT和Hob中检测了HIV gp120 RNA。结论先前的报道认为胎盘屏障可能解释了HIV感染母亲的低传播率，但我们认为，胎盘后屏障可能保护HIV从感染的胎盘向胎儿的垂直传播。

Recent advances in perinatal care for HIV infected mothers decreased vertical transmission rates as low as 2% in Japan. However the mechanism of transplacental infection of HIV is still enigmatic and uncontrollable. In this study, we described placental pathology in HIV infected mothers in order to examine patho-physiology of congenital HIV infection and morphological basis of possible placental barriers.Subjects and methods Twelve placental samples were obtained from HIV infected mothers by AIDS working group of Japan. All cases were delivered by elective caesarean section before onset of labour. Eleven of 12 patients received oral AZT administration. No neonates delivered showed evidence of congenital infection. We examined placentae by HE stain, TUNEL and immunohistochemiistry. Various components of placental cells were separated by MACS coated with anti EGF-R, erb-B2 and CD11b which recognize villous trophoblasts (VT), extravillos trophoblasts (EVT) and Hofbauer cells (Hob) respectively. Presence of HIVgp120 RNA was examined by RT-PCR.Results By routine histological study, we observed increased frequency of intervillitis and apoptosis in placentae delivered from HIV infected patients. By quantitative analysis using TUNEL stain, we observed increased numbers of apoptotic scores. Immunohistochemical stain revealed presence of HIV p24 antigen in 2 of 12 placentae. P24 was localized both in VT and Hob. Using antigenically separated placental cells, we detected HIV gp120 RNA both in VT, EVT and Hob.Conclusion Previous reports suggest possible placental barrier to explain low transmission rates of HIV from infected mothers However we suggest, possible postplacental barriers which protect vertical transmission of HIV from infected placentae to fetuses.