Trends in mucosal immunity in Antarctica during six Australian winter expeditions

The mucosal immune status of Australian Antarctic personnel was monitored during six wintering expeditions at two Australian Antarctic Research Stations, Casey in 1992, 1993, 1994, and Mawson in 1992, 1995, 1996. Salivary immunoglobulin and albumin levels were examined for differences between stations and expeditions, and for monthly changes over the expedition year. Salivary IgA and IgM concentrations were on average higher for the 1993 Casey expeditioners, and all salivary protein levels were lower for 1996 Mawson expeditioners compared to levels of the other expeditions. The change in salivary IgA and IgM concentrations over the 1-year period revealed a consistent pattern between expeditions. Salivary IgA levels were lower in March, April and May compared to other months of the year (P = 0.0002). Salivary IgM levels were lowest in the first 4 months of the year, with peak levels in June and July (P < 0.0001). There were no changes in salivary IgG and albumin concentrations over the expedition year. Though the cause of the changes in salivary IgA and IgM levels over the year is unknown, the changes could reflect alterations in mucosal immunity in response to stressors associated with isolation.