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K.P. High, J. Sinclair, L.H. Easter, D. Case, F.H. ChiltoN
1. Department of Internal Medicine, Sections of Infectious Diseases, Hematology/Oncology
and Pulmonary/ Critical Care, Wake Forest University School of Medicine,
Winston Salem, NC 27157-1042 ; Financial Support: This study was supported
by the following grants: Wake Forest University Nutrition Center Pilot
Grant; The General Clinical Research Center of Wake Forest University
School of Medicine, MO1-RR07122; NIH, AI-42022; Address Correspondence
to: Kevin P. High, M.D., M.Sc., Infectious Diseases Section, Wake Forest,
University School of Medicine, Winston Salem, NC 27157-1042, Phone: 336-716-4584,
Fax: 336-716-3825, Email: khigh@wfubmc.edu
Abstract: Unknown factors present in the serum of older adults impair
lymphocyte function and may be responsible for anergy (absence of delayed-type
hypersensitivity (DTH)) present in many older adults. Polyunsaturated
fatty acids (PUFAs) and their metabolites are immunomodulatory and may
play a role in clinical conditions of advanced age, including immune dysfunction.
We hypothesized that PUFAs could be the factor(s) present in serum that
contribute to impaired immune responses in older adults. Prior studies
of serum PUFAs in older adults neither adequately control dietary PUFA
intake, nor investigated the relationship of PUFAs and DTH responses.
We determined serum PUFA concentrations in young adults with normal immune
responses, and older adults with impaired (anergic elderly) or normal
immunity (nonanergic elderly) before and after administering a standardized
diet. After controlling for dietary intake, advancing age was associated
with markedly higher serum concentrations of arachidonic acid (AA), dihomo-g-linoleic
acid (DGLA), and eicosapentaenoic acid (EPA) and a lower AA:EPA ratio.
Other serum PUFAs and the AA:DGLA ratio were unaffected by age. However,
there was no difference between older adults with or without anergy. These
data suggest advanced age is associated with marked alterations of serum
PUFAs that are only apparent after strictly controlling dietary intake.
However, there was no association of serum PUFA concentrations with DTH
status among older adults.
Key words: Aging/Aged, Polyunsaturated Fatty Acids, Arachidonic Acid,
Eicosapentaenoic Acid, Dihomogammalinoleic Acid, Nutrition
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