Transplacental transfer of RSV antibody in Australian First Nations infants

Abstract

Respiratory syncytial virus (RSV) is the leading cause of acute lower respiratory infection hospitalisations in Aboriginal infants specifically those aged <6 months.Maternally derived RSV antibody (Ab) can protect against severe RSV disease in infancy. However, the efficiency of transplacental transfer of maternal anti-RSV Ab remains unknown in Aboriginal infants. We characterised RSV Ab in Australian First Nations mother-infant pairs (n = 78). We investigated impact of covariates including low birthweight, gestational age (GA), sex of the baby, maternal age and multiparity of the mother on cord to maternal anti-RSV Ab titre ratio (CMTR) using multivariable logistic regression model. All (n = 78) but one infant was born full term (median GA: 39 weeks, interquartile range: 38-40 weeks) and 56% were males. The mean log 2 RSV Ab titre was 10.7 (SD± 1.3) in maternal serum and 11.0 (SD ± 1.3) in cord serum at birth; a ratio of 1.02 (SD ± 0.06). One-third of the pairs had a CMTR of <1 indicating impaired transfer. Almost 9% (7/78) of the term infants had cord RSV Ab

Efficiency of transplacental transfer of respiratory syncytial virus (RSV) specific antibodies among pregnant women in Kenya

“…Previous studies have shown that transplacental transfer of RSV-specific antibody to the infant is usually efficient with a cord blood to maternal blood antibody titre ratio of ≥ 1 [14][15][16] . This is because IgG antibody is actively transported across the syncytiotrophoblast cells rather than a passive diffusion process which is why transplacental transfer is expected be more than one 17 .…”

“…This is because IgG antibody is actively transported across the syncytiotrophoblast cells rather than a passive diffusion process which is why transplacental transfer is expected be more than one 17 . Transplacental transfer efficiency has been defined as either normal or impaired in other studies 16,18 . Where the cord to maternal titre ratio (CMTR) is one or greater than one, this is considered as a normal or efficient transfer, while a CMTR of less than one is considered as an impaired transfer 16 .…”

“…Transplacental transfer efficiency has been defined as either normal or impaired in other studies 16,18 . Where the cord to maternal titre ratio (CMTR) is one or greater than one, this is considered as a normal or efficient transfer, while a CMTR of less than one is considered as an impaired transfer 16 .…”