Can an increased level of circulating IL-8 be a predictor of human longevity?
BACKGROUND
Interleukin-6 (IL-6) and IL-8 are considered to be potent inflammatory agents. However, IL-8 has also been reported to serve as an organ protective factor. The goal of our study was to compare the circulating levels of IL-8 and IL-6 in C-reactive protein (CRP)-negative subjects of different ages.


METHODS
Seventy subjects living in the Wielkopolska region were enrolled into the study and divided into three groups: group 1-30 young healthy subjects 21-37 years of age; group 2-30 healthy elderly individuals, age 65-87; group 3-10 centenarians (100-105 years). In all of these subjects, serum levels of IL-6 and IL-8 were assessed with an enzyme-linked immunosorbent assay.


RESULTS
Concerning IL-6, both the serum concentration and the frequency of results above the sensitivity limit were comparable in all groups. With respect to IL-8, the frequency of results beyond the sensitivity limit in groups 1 and 2 did not differ significantly (5/30 and 8/30, respectively). By contrast, the majority of subjects from group 3 had an IL-8 level above the limit (9 out of 10; p<0.0001 vs. group 1 and p=0.0007 vs. group 2). In addition, the serum concentration of IL-8 in group 3 was higher than in both the other groups (p<0.01). Moreover, there was a positive correlation between the age of analysed subjects and their level of IL-8 (r=0.450; p<0.0001).


CONCLUSIONS
It seems possible that an association of an increased serum level of IL-8 and a low level of IL-6 is related to longevity.
Wieczorowska-Tobis
Katarzyna
K
Department of Pathophysiology, Medical University of Poznań, Poznań, Poland. kwt@tobis.pl
Niemir
Zofia I
ZI
Podkówka
Renata
R
Korybalska
Katarzyna
K
Mossakowska
Małgorzata
M
Breborowicz
Andrzej
A
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002097:C-Reactive Protein / Q000032:analysis; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D015850:Interleukin-6 / Q000097:blood; D016209:Interleukin-8 / Q000097:blood*; D008136:Longevity; D008297:Male; D011237:Predictive Value of Tests; D012015:Reference Standards; D012680:Sensitivity and Specificity
D015850:Interleukin-6; D016209:Interleukin-8; D002097:C-Reactive Protein