Role of Maternal Antibodies in Infants with Severe Diseases Related to Human Parechovirus Type 3.

Yuta Aizawa,Kanako Watanabe,Isao Hasegawa,Harunobu Hirano,Akihiko Saitoh,Tomohiro Oishi

doi:10.3201/eid2111.150267

Abstract

Human parechovirus type 3 (HPeV3) is an emerging pathogen that causes sepsis and meningoencephalitis in young infants. To test the hypothesis that maternal antibodies can protect this population, we measured neutralizing antibody titers (NATs) to HPeV3 and other genotypes (HPeV1 and HPeV6) in 175 cord blood samples in Japan. The seropositivity rate (≥1:32) for HPeV3 was 61%, similar to that for the other genotypes, but decreased significantly as maternal age increased (p<0.001). Furthermore, during the 2014 HPeV3 epidemic, prospective measurement of NATs to HPeV3 in 45 patients with severe diseases caused by HPeV3 infection showed low NATs (≤1:16) at onset and persistently high NATs (≥1:512) until age 6 months. All intravenous immunoglobulin samples tested elicited high NATs to HPeV3. Our findings indicate that maternal antibodies to HPeV3 may help protect young infants from severe diseases related to HPeV3 and that antibody supplementation may benefit these patients.

Highlights

Human parechoviruses (HPeVs) are small, nonenveloped, single-stranded, positive-sense RNA viruses classified in the genus Parechovirus of the family Picornaviridae [1]
neutralizing antibody titers (NATs) in Patients with Severe Diseases Related to Human parechovirus type 3 (HPeV3) During the study period, 46 patients had a diagnosis of severe diseases related to HPeV, determined by PCR analysis of serum or cerebrospinal fluid (CSF) samples
The VP1 region could not be successfully amplified in 1 sample, so HPeV3 infection was diagnosed on the basis of a positive PCR result and a >4-fold increase in NATs to HPeV3

Summary

Introduction

Human parechoviruses (HPeVs) are small, nonenveloped, single-stranded, positive-sense RNA viruses classified in the genus Parechovirus of the family Picornaviridae [1]. Neutralizing antibody titers (NATs) have been reported as lower for mothers of infants with HPeV3 infection than for mothers of infants with other viral infections [16], little is known about patients infected with HPeV3 [15] Such data might help determine why severe diseases related to HPeV3 develop in some neonates and young infants. We measured NATs to HPeVs in cord blood from newborns and in serum samples from neonates and young infants with diseases related to HPeV3 infection who were admitted to hospitals in Niigata, Japan. In the latter group, samples were obtained from disease onset through convalescence.

Methods

Results

Conclusion