Secretory IgA antibody to rotavirus in human milk 6--9 months postpartum

A comparison of seasonal variations in rotavirus antibodies in the breast milk of Swedish and Bangladeshi mothers

AIM

The rotavirus has been identified as the most common cause of severe gastroenteritis in young children. This study compared the levels of rotavirus-specific antibodies in breast milk and serum samples in Swedish and Bangladeshi mothers to identify any seasonal variations.

METHODS

Breast milk and serum samples were collected from 69 Swedish and 52 Bangladeshi mothers during all months of the year. Sera were analysed for Immunoglobulin A (IgA) and Immunoglobulin G (IgG) titres and breast milk for secretory IgA (SIgA) antibody levels against rotavirus.

RESULTS

Significantly, higher SIgA antibody levels against rotavirus were found in breast milk from Bangladeshi than Swedish mothers (p < 0.0001). Seasonality of rotavirus antibody levels was only detected in breast milk from Swedish mothers, with samples collected during the spring having significantly higher rotavirus titres than samples collected during the autumn (p = 0.0203).

CONCLUSION

This study found significantly higher SIgA antibody levels against rotavirus in breast milk from Bangladeshi than Swedish mothers, together with a seasonal variation among Swedish mothers only. These results suggest that Swedish children who are being breastfed should ideally be vaccinated during seasons when the rotavirus antibody levels in breast milk are low.

Fluctuation of specific IgA antibodies in human milk

The concentration of secretory IgA and the levels of IgA specific antibodies against Escherichia coli labile-toxin, Shigella flexneri 6, and rotaviruses were determined in milk samples obtained serially from women during the first 16 weeks postpartum. The mean concentration of secretory IgA followed the expected pattern; the levels of specific antibodies fluctuated in an unpredictable manner and independently of milk secretory IgA content, becoming undetectable in many instances. Under some circumstances, continued breast-feeding may not guarantee continued intake of antibodies against intestinal pathogens by the breast-fed infant.

Etude épidémiologique de gastroentérites infantiles d'origine virale dans la région amienoise

A systematic survey was carried on stools from 130 children suffering of acute gastroenteritis. Electron microscopy, enzymo-linked immunosorbent assay (ELISA) and counter electrophoresis were employed. This survey allowed to the detection by electron microscopy of Rotavirus (40 cases), Coronaviruses (3 cases), Astroviruses (2 cases), Adenoviruses (2 cases) and Small Round Viruses (1 case). Serological tests (complement fixation, ELISA and counter electrophoresis) done with 86 sera showed a good correlation with results obtained with electron microscopy.

Cord blood and breast-milk antibodies in neonatal rotavirus infection

Studies were carried out during an outbreak of rotavirus type 2 infection in a neonatal nursery to determine the protective role of antibodies in cord blood and breast milk. The range, distribution, and geometric mean titres of rotavirus-specific antibody in the cord blood were similar among rotavirus-positive and rotavirus-negative neonates, and the amount of virus excreted did not correlate with antibody levels. Despite the protective effect of breast feeding, the pattern of rotavirus-specific IgA and IgG antibodies in the expressed breast milk of mothers of babies who were rotavirus excreters and non-excreters was similar. Nevertheless, a higher proportion of expressed breast milk samples contained rotavirus-specific IgA group 2 (92%) and type 2 (97%) specific antibodies than type I (67%) antibodies, and the geometric mean titres of group 2 and type 2 specific antibodies were tenfold higher than type I antibodies. Among breast-fed babies who excreted rotavirus there was no correlation between type 2 rotavirus-specific IgA antibodies in expressed breast milk and the amount of neonatal virus excretion. These studies suggest that factors other than the rotavirus antibodies in expressed breast milk are of importance in preventing rotavirus infection in newborn infants.

Secretion of respiratory syncytial virus inhibitors and antibody in human milk throughout lactation

Neutralising inhibitors to respiratory syncytial (RS) virus have been demonstrated in the whey of most samples of human milk tested. Although high titres were secreted in colostra of some mothers (1/10-1/2,560; median 1/40) inhibitor levels in milk collected after the first week of lactation were uniformly low (median 1/10). High neutralising titres correlated with high colostral levels of specific antiviral IgA but, unlike neutralising activity, IgA antiviral antibody persisted in the milk of only four of 18 mothers. Similarly, antiviral IgG and IgM antibodies were not generally detected after the first post-partum week. Differences in antibody secretion among mothers did not correlate with differences in total protein or total immunoglobulin secretion, and appeared to reflect maternal immune status. In one mother a marked rise in specific antiviral IgA and IgG secretions during the second and third months of lactation suggested a response to virus infection. The relevance of maternal immunity and colostral and milk antiviral antibody to protection of breast-fed babies from RS-virus bronchiolitis is discussed.

Epidemic viral gastroenteritis

Epidemic viral gastroenteritis is a significant world wide problem. In developed countries, gastroenteritis accounts for significant morbidity and loss of time from work; in the Third World it is the leading cause of mortality among infants and children. Recent technologic advances have been associated with an explosion of research activity. Two virus groups, the Norwalk-like agents and the rotaviruses, are currently accepted as causative agents of viral gastroenteritis in man. The problem of viral gastroenteritis is reviewed both from a current and a historic perspective.