Serological studies on mother-to-child transmission and virulence as an opportunistic pathogen of human herpesvirus-6 (HHV-6)

对47例经血清学确诊的人类疱疹病毒6型(HHV-6)感染患者的临床表现进行了分析。ES发病年龄集中在6~9月龄，6月龄达高峰。在我们的血清流行病学研究中，HHV-6的母源抗体在同一时期内消失。在47名患者中。3例出生后2个月内被ES攻击，其母亲均为阳性。这些结果提示ES的发病年龄是由母源HHV-6抗体消失所决定的。新生儿重症监护病房(NICU)1年以上的婴儿与其母亲一起进行了HHV-6抗体检测。他们的母亲都是HHV-6阳性，6名婴儿中有5名HHV-6血清阳性。更重要的是。21名儿童被一家孤儿院收容…对3个月前出生的婴儿进行HHV-6抗体检测。这些儿童中HHV-6的年龄特异性血清阳性率与普通儿童人群相似。这些数据说明母婴之间的密切接触并不是婴儿感染HHV-6的必要条件。为了获得免疫受损状态下HHV-6毒力的基本数据，我们评估了HHV-6是否像其他疱疹病毒一样发生再激活或再感染。23例ES二次发作的患者中。3例HHV-6 IgG抗体滴度明显升高，5例有发热史的患者中有2例也有升高。这些结果提示HHV-6的重新激活或再感染可能在ES的第二次发作中起作用。我们通过问卷调查的方式从57名在九州大学医院接受培训的儿科医生那里获得了他们自己12个月以上儿童ES的病史。他们的115个孩子中有70个(61%)有过临床ES。ES在日本的发病率远高于美国(约30%)。较少

The clinical findings of 47 patients with exanthema subitum (ES) serologically confirmed human herpesvirus-6 (HHV-6) infection were analyzed. The onset age of ES concentrated between 6 and 9 months old, pepeaked at 6 months old. In our seroepidemiologic study, the maternal antibody to HHV-6 disappeared within the same period. Among the 47 patients. 3 were attacked by ES within 2 months after their birth and all of their mothers mothers were seropositive. These results suggested that the onset age of ES is determined by the disappearance of maternal antibody to HHV-6. No correlation was observed between the onset age and mode of feeding (e.g. breast bottle and mixed).Antibodies to HHV-6 in the infants who have been admitted in the neonatal intensive care unit (NICU) for more than 1 year were tested together with their mothers. All of their mothers were seropositive to HHV-6 and 5 of the 6 infants were seropositive to HHV-6. Furthermore. 21 children who have been admitted in an orphanage … More before 3 month of ages were tested for their antibodies to HHV-6. Age specific seroprevalence of HHV-6 in these children was similar to that of the ordinary child population. These data elucidated that intimate contact of mother and child is not neccesary for the establishment of HHV-6 infection in infants.In order to obtain basic data concerning the virulence of HHV-6 in the immunocompromised state, we evaluated whether or not reactivation or reinfection of HHV-6 occurs as other herpesviruses. Among the 23 patients with second attacks of ES. 3 showed significant rises in the HHV-6 lgG antibody titers and 2 of the 5 patients with previous afebrile attacks also showed rises. These results suggest possible role of HHV-6 reactivation or reinfection in some second attack of ES.We have obtained informations from 57 pediatricians who had been trained at Kyushu University Hospital on the history of ES of their own children older than 12 months of age by a questionnaire. Seventy of 115 their children (61%) have had clinical ES. This attack rate of ES in Japan is much higher than that in U. S. A. (approximately 30%). Less