Monitoring temporary immunodepression by flow cytometric measurement of monocytic HLA-DR expression: a multicenter standardized study.
BACKGROUND
Single-center trials have shown that monocytic HLA-DR is a good marker for monitoring the severity of temporary immunodepression after trauma, major surgery, or sepsis. A new test for measuring monocytic HLA-DR is now available.


METHODS
We evaluated a new test reagent set for monocytic HLA-DR expression (BD Quantibritetrade mark HLA-DR/Monocyte reagent; Becton Dickinson) in single-laboratory and interlaboratory experiments, assessing preanalytical handling, lyse-no-wash (LNW) vs lyse-wash (LW) values, reference values, and the effect of use of different flow cytometers and different instrument settings on test variance.


RESULTS
For preanalytical handling, EDTA anticoagulation, storage on ice as soon as possible, and staining within 4 h after blood collection gave results comparable to values obtained for samples analyzed immediately after collection (mean increase of approximately 4% in monocytic HLA-DR). Comparison of LNW and LW revealed slightly higher results for LNW ( approximately 18% higher for LNW compared with LW; r = 0.982). Comparison of different flow cytometers and instrument settings gave CVs <4%, demonstrating the independence of the test from these variables and suggesting that this method qualifies as a standardized test. CV values from the interlaboratory comparison ranged from 15% (blood sample unprocessed before transport) to 25% (stained and fixed before transport).


CONCLUSIONS
For the BD Quantibrite HLA-DR/Monocyte test, preanalytical handling is standardized. Single-laboratory results demonstrated the independence of this test from flow cytometer and instrument settings. Interlaboratory results showed greater variance than single-laboratory values. This interlaboratory variance was partly attributable to the influence of transport and can be reduced by optimization of transport conditions.
Döcke
Wolf-Dietrich
WD
Institute of Medical Immunology, Charité-Campus Mitte, Humboldt University of Berlin, and University Hospital, Charité Berlin, Germany.
Höflich
Conny
C
Davis
Kenneth A
KA
Röttgers
Karsten
K
Meisel
Christian
C
Kiefer
Paul
P
Weber
Stefan U
SU
Hedwig-Geissing
Monika
M
Kreuzfelder
Ernst
E
Tschentscher
Peter
P
Nebe
Thomas
T
Engel
Andrea
A
Monneret
Guillaume
G
Spittler
Andreas
A
Schmolke
Kathrin
K
Reinke
Petra
P
Volk
Hans-Dieter
HD
Kunz
Dagmar
D
D005434:Flow Cytometry / Q000379:methods*; D005786:Gene Expression Regulation; D006684:HLA-DR Antigens / Q000032:analysis* / Q000276:immunology*; D006801:Humans; D007108:Immune Tolerance / Q000276:immunology*; D009000:Monocytes / Q000187:drug effects / Q000276:immunology* / Q000378:metabolism*
D006684:HLA-DR Antigens