title: Need for an external proficiency testing program for cytokines, chemokines, and plasma markers of immune activation.
abstract: An external evaluation program for measuring the performance of laboratories testing for cytokines and immune activation markers in biological fluids was developed. Cytokines, chemokines, soluble cytokine receptors, and other soluble markers of immune activation (CSM) were measured in plasma from a healthy human immunodeficiency virus (HIV)-seronegative reference population and from HIV-seropositive individuals as well as in supernatant fluids from in vitro-stimulated human immune cells. The 14 components measured were tumor necrosis factor (TNF) alpha, gamma interferon, interleukin-1 (IL-1), IL-2, IL-4, IL-6, IL-10, Rantes, MIP-Ia, MIP-Ibeta, soluble TNF receptor II, soluble IL-2 receptor alpha, beta(2)-microglobulin, and neopterin. Twelve laboratories associated with the Adult and Pediatric AIDS Clinical Trial Groups participated in the study. The performance features that were evaluated included intralaboratory variability, interlaboratory variability, comparison of reagent sources, and ability to detect CSM in the plasma of normal subjects as well as the changes occurring in disease. The principal findings were as follows: (i) on initial testing, i.e., before participating in the program, laboratories frequently differed markedly in their analytic results; (ii) the quality of testing of a CSM in individual participating laboratories could be assessed; (iii) most commercial kits allowed distinction between normal and abnormal plasma CSM levels and between supernatants of stimulated and unstimulated cells; (iv) different sources of reagents and reference standards frequently provided different absolute values; (v) inexperienced laboratories can benefit from participating in the program; (vi) laboratory performance improved during active participation in the program; and (vii) comparability between analyses conducted at different sites can be ensured by an external proficiency testing program.
authors.affiliation: University of California, Los Angeles, USA. jlfahey@microimmun.medsch.ucla.edu
authors.forename: J L
authors.initials: JL
authors.lastname: Fahey
authors.forename: N
authors.initials: N
authors.lastname: Aziz
authors.forename: J
authors.initials: J
authors.lastname: Spritzler
authors.forename: S
authors.initials: S
authors.lastname: Plaeger
authors.forename: P
authors.initials: P
authors.lastname: Nishanian
authors.forename: J L
authors.initials: JL
authors.lastname: Lathey
authors.forename: J
authors.initials: J
authors.lastname: Seigel
authors.forename: A L
authors.initials: AL
authors.lastname: Landay
authors.forename: R
authors.initials: R
authors.lastname: Kilarui
authors.forename: J L
authors.initials: JL
authors.lastname: Schmitz
authors.forename: C
authors.initials: C
authors.lastname: White
authors.forename: D W
authors.initials: DW
authors.lastname: Wara
authors.forename: R
authors.initials: R
authors.lastname: Akridge
authors.forename: J
authors.initials: J
authors.lastname: Cutili
authors.forename: S D
authors.initials: SD
authors.lastname: Douglas
authors.forename: J
authors.initials: J
authors.lastname: Reuben
authors.forename: W T
authors.initials: WT
authors.lastname: Shearer
authors.forename: M
authors.initials: M
authors.lastname: Nokta
authors.forename: R
authors.initials: R
authors.lastname: Polland
authors.forename: R
authors.initials: R
authors.lastname: Schooley
authors.forename: D
authors.initials: D
authors.lastname: Asthana
authors.forename: Y
authors.initials: Y
authors.lastname: Mizrachi
authors.forename: M
authors.initials: M
authors.lastname: Waxdal
mesh_terms: D000328:Adult; D015415:Biomarkers; D019411:Clinical Laboratory Techniques / Q000592:standards*; D016207:Cytokines / Q000097:blood*; D015658:HIV Infections / Q000276:immunology*; D006801:Humans; D007107:Immune System; D016730:Program Development
chemical_list: D015415:Biomarkers; D016207:Cytokines