AGE-RELATED-CHANGES IN IMMUNOGLOBULIN ISOTYPES IN WHOLE AND PAROTID-SALIVA AND SERUM IN HEALTHY-INDIVIDUALS

Mucosal infections account for the majority of infections seen in elde rly people, but little is known of whether mucosal immunity decrease w ith age. The objective of this study was to investigate the effect of age on the levels of salivary and serum immunoglobulins and the saliva ry immunoglobulin secretion rates in a healthy adult population. Healt hy subjects (116 total) were divided into the following age groups: 20 -39; 40-59; 60-79 and >80 years. Unstimulated (resting) whole and stim ulated parotid saliva and serum were collected from all participants. Salivary and serum immunoglobulins were quantified by enzyme-linked im munosorbent capture assays. The levels of serum immunoglobulin G (IgG) and IgM were significantly reduced in the oldest age group, whereas n o significant reduction in the level of IgA with age was observed. The IgG and IgA levels in whole saliva increased significantly in the old est age group D, but no changes were detected in IgM levels. No signif icant changes in any immunoglobulin levels with age were found in paro tid saliva. However, significant reductions in the secretion rates of IgA and IgM, but not IgG, in whole saliva were detected in the oldest age group. No significant changes in the secretion rates in parotid sa liva were found with age, Our results demonstrate a decline in immunog lobulin secretion rates in saliva and in circulating immunoglobulin co ncentrations with increased age, which may contribute to the increased susceptibility of elderly individuals to infectious diseases.