Role of Maternal Antibodies in Infants with Severe Diseases Related to Human Parechovirus Type 31

Abstract

Maternal antibodies may protect infants from severe illness caused by this pathogen.

Seroepidemiology of human parechovirus types 1, 3, and 6 in Yamagata, Japan, in 2014

“…). These findings are similar to those for seroprevalence for HPeV3 in cord blood samples, which has been shown to decline with increasing maternal age . Westerhuis et al .…”

“…reported high concentrations of NT Abs against HPeV1 1 year after infection, whereas they detected no NT Abs against HPeV3 after the same interval . These findings raise the question of whether HPeV3 infection confers lifelong protection, as previously suggested . We have reported that most adult patients with myalgia are aged between 20 and 40 years; that is, are of child‐rearing age and our seroepidemiological analysis clearly indicates that some individuals of child‐rearing age have no or low NT Ab titers (≤1:16).…”

“…Aizawa et al . reported NT Ab titers against HPeV3 of ≤1:16 in 45 neonates and young infants with severe diseases related to HPeV3, and chose a titer of ≥1:32 as the NT titer necessary for preventing infection . We have previously reported that NT Ab titers were ≤1:16 in the acute phase in all of 12 adult patients with epidemic myalgia associated with HPeV3 infections from whom serum specimens had been collected within 7 days of the onset of illness .…”

Human picornaviruses associated with neurological diseases and their neutralization by antibodies

“…A study of sera from different populations in Finland and the Netherlands only revealed neutralizing responses to HPeV-3 in about 10 % of the samples and very low titres of neutralizing antibodies post-infection [175]. By contrast, researchers in Japan detected neutralizing responses to HPeV-3 in 67 % of individuals between 7 months and 40 years old [94], and reported high titres of neutralizing antibodies after 3 months post-infection in all studied individuals [176]. The virus strains used in the European and Japanese studies were different, suggesting that there is antigenic variation in HPeV-3.…”

“…Developing vaccines does not seem feasible because the subjects of severe HPeV-3 infections are infants. Passive immunization protects against HPeV-3 [176] and thus the development of therapeutic antibodies is a necessity for which studies of HPeV-3 antigenicity are required.…”