Increased soluble tumor necrosis factor receptor levels in the serum of elderly people.
BACKGROUND
Soluble (s) forms of tumor necrosis factor (TNF) receptors are the only natural molecules known to interfere with TNF activity by competing for TNF binding with receptors on target cells. In a variety of pathologic situations, the concentrations of sTNF receptors (R) increase.


OBJECTIVE
To discuss possible causes of increased risks for infectious disease and cancer seen in the elderly.


METHODS
The participants were healthy subjects (n = 48) of three age groups (young, middle-aged, and elderly). Patients with senile dementia of Alzheimer type (n = 25) were also studied. For detection of cytokines, interleukin (IL) 1alpha, IL-1beta, IL-6, macrophage colony-stimulating factor (M-CSF), granulocyte colony-stimulating factor, and TNF-alpha were measured in serum by enzyme-linked immunosorbent assays, as were soluble (s) IL-1 receptor antagonist (IL-1ra), sIL-6R, p55sTNF-R, and p75sTNF-R.


RESULTS
IL-1alpha, IL-1beta, IL-6, and TNF-alpha were not detected, and sIL-6R and IL-1ra concentrations were not significantly different between the three age groups. However, sTNF-R and M-CSF were increased in sera from the elderly, both healthy and demented. A significant correlation was seen between sTNF-R and M-CSF concentrations.


CONCLUSIONS
Increased sTNF-R levels may oppose the physiologic and protective effects of TNF by interference with its receptor binding. This interaction may contribute to the susceptibility of the elderly to infectious and neoplastic diseases.
Hasegawa
Y
Y
Department of Neurology, Nagoya City Koseiin Geriatric Hospital, Japan. yhasegaw@bc4.so-net.ne.jp
Sawada
M
M
Ozaki
N
N
Inagaki
T
T
Suzumura
A
A
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000097:blood*; D000544:Alzheimer Disease / Q000097:blood; D015703:Antigens, CD / Q000097:blood; D005260:Female; D006801:Humans; D016173:Macrophage Colony-Stimulating Factor / Q000097:blood; D008297:Male; D008875:Middle Aged; D018124:Receptors, Tumor Necrosis Factor / Q000097:blood*; D047888:Receptors, Tumor Necrosis Factor, Type I; D047889:Receptors, Tumor Necrosis Factor, Type II; D012016:Reference Values; D012995:Solubility
D015703:Antigens, CD; D018124:Receptors, Tumor Necrosis Factor; D047888:Receptors, Tumor Necrosis Factor, Type I; D047889:Receptors, Tumor Necrosis Factor, Type II; D016173:Macrophage Colony-Stimulating Factor