Influence of age and carriage status on salivary IgA to Neisseria meningitides

MORTON, R. E.
STUART, J.
CHRISTENSEN, H.
BORROW, R.
GUTHRIE, T.
DAVENPORT, V.
FINN, A.
WILLIAMS, A.
HEYDERMAN, R. S.

¹Department of Pathology and Microbiology, School of Medical Sciences, University of Bristol, Bristol, UK
²Health Protection Agency, Bristol, UK
³Communicable Disease Surveillance Centre (Southwest), Health Protection Agency, Gloucester, UK
⁴4 HP A Meningococcal Reference Unit, Medical Microbiology Partnership, Manchester Royal Infirmary, Manchester, UK
⁵Institute of Child Health, University of Bristol, Bristol, UK
⁶6 Avon Longitudinal Study of Parents and Children, Bristol, UK

^*Author for correspondence: R. E. Horton, Department of Pathology and Microbiology, School of Medical Sciences, University of Bristol, University Walk, Bristol, BS8 1TD, UK. (Email: [email protected])

(Accepted 10 February 2005)

Epidemiology & Infection 133(5):p 883-889, October 2005.

SUMMARY

Asymptomatic carriage of Neisseria meningitidis is common (5–35% of individuals) while the incidence of invasive meningococcal disease is fairly low (≤ 1–5 per 100000 per annum in Europe). Naturally acquired protective immunity may account for this difference. In this study, we investigated the relationship between anti-meningococcal salivary IgA and age and carriage. We showed that salivary IgA to a range of meningococcal antigens increased successively with age with some specificity for commonly circulating serosubtypes. In a group of 258 students 37 (14 %) of whom were carriers of N. meningitidis serogroup B, higher levels of specific IgA were associated with carriage. Stratified analysis revealed a positive relationship between smoking and specific anti-JV. meningitidis IgA independent of current carriage, weighted odds ratio (OR) 4–1 (95% CI 1-1-18) and OR 3–8 (95% CI 0-96-16) for reference strains B:1:P1.14 and B:4:P1.5,4 respectively. These data implicate IgA as a factor in host defence from meningococcal invasion, although the precise mechanisms remain uncertain.