Immune function among normal Guamanians of different age.

To determine if immune function differed in normal Guamanian Chamorros at various ages we measured the percentage and total numbers of lymphocytes and T-lymphocytes, their response to phytohemagglutinin (PHA), and serum levels of immunoglobulin A, G, and M in subjects 20 to 83 years of age. Regression analysis showed highly significant negative correlations for total lymphocytes and T-cells with age and a less significant negative correlation for PHA response with age in this population. Serum IgA levels increased with age, IgM levels declined, and IgG levels were unchanged. These findings are similar to, but less marked than, immunologic aberrations previously observed in Guamanians with amyotrophic lateral sclerosis or Parkinsonism-dementia. The occurrence of prominent differences in immune functions between younger and older individuals in a population where neurofibrillary degeneration in brain occurs at an early age and neurodegenerative and other age-related diseases are highly prevalent suggests the possibility that immunity and age-associated degenerative disease may be linked etiologically in this population.