Inter- and intra-individual variation in tests of cell-mediated immunity in young and old women.
Exploring means to maintain or improve immunity in older persons has been receiving attention. To establish relationships between immune function and variables of interest, it is important to determine these variables accurately and precisely. Precision relates to the degree of variation in the laboratory test. The nature and magnitude of variability in tests of immune function has not been described extensively. We examined inter- and intra-individual variation in tests of cell-mediated immunity (CMI) in generally healthy and well-nourished young (20-40 years; n=15) and old (60-80 years; n=15) women. Subjects provided blood samples on 2 days within a week to determine leukocyte subsets, T-cell proliferation response to phytohemagglutinin A and concanavalin A, and interleukin (IL)-1beta, IL-2 and IL-6 production by stimulated mononuclear cells. Intra-individual variation was partitioned into day-to-day biological and analytical variation. Inter-individual variation was greater than intra-individual variability for most tests of CMI for both age groups. Furthermore, all CMI tests exhibited large day-to-day intra-individual variation (CV approximately 15% or greater) which was primarily due to biological rather than analytical sources, for both age groups. In conclusion, both age groups showed large between-person and considerable within-person variation in CMI tests. Therefore, assessment of CMI based on a single blood draw may not provide a reliable estimate of immune function.
Graduate Program in Nutrition, Department of Nutritional Sciences, The Pennsylvania State University, S-126 Henderson South Bldg., University Park 16802, USA.
Roshni R
RR
Molls
Namanjeet
N
Ahluwalia
Tara
T
Fick
Andrea M
AM
Mastro
David
D
Wagstaff
Gordon
G
Handte
Rick
R
Ball
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000276:immunology*; D002455:Cell Division / Q000187:drug effects / Q000276:immunology; D003208:Concanavalin A / Q000494:pharmacology; D005260:Female; D006801:Humans; D007111:Immunity, Cellular / Q000502:physiology*; D016131:Lymphocyte Subsets / Q000166:cytology / Q000502:physiology; D008875:Middle Aged; D009752:Nutritional Status; D010835:Phytohemagglutinins / Q000494:pharmacology
D010835:Phytohemagglutinins; D003208:Concanavalin A