A standardized procedure for quantitation of CD11b on polymorphonuclear neutrophil by flow cytometry: potential application in infectious diseases

Abstract

An up-regulation of the surface marker CD11b has been demonstrated during polymorphonuclear (PMN) cell activation. CD11b over-expression is often associated with inflammation and is considered as an early marker of infection. However, the absence of standardized assay and the variability of preanalytical settings leading to PMN artifactual activation have compromised the interest of this marker. In the present study a standardized quantitative flow cytometry assay directly performed in whole blood has been used to determine CD11b expression on PMN cells. The results indicate that quantitative flow cytometry can provide consistent CD11b density values between laboratories provided that a calibration system is used including specific calibrators, reagents and protocols. This method allowed us to evidence an up-regulation of CD11b expression for infected patients. This quantitation is a standardized and potentially useful method in clinical situations implying quantitative CD11b expression variations.

Kinetics of leukocyte CD11b and CD64 expression in severe sepsis and non‐infectious critical care patients

“…Standardization of both the pre‐analytical and analytical phase is a prerequisite for reliable and repeatable flow cytometry results. It is known from previous studies that CD11b expression is highly affected by pre‐analytical factors . Moreover, we have shown that also monocyte CD64 expression may be affected by the pre‐analytical procedures .…”

Flow cytometric patterns in blood from dogs with non‐neoplastic and neoplastic hematologic diseases using double labeling for CD18 and CD45

“…Moreover, the FL1 vs FL2 cytogram allowed us to detect a left shift because of the lower expression of CD18 in immature neutrophils 26. A quantitative assay to detect integrin expression in neutrophils has been reported as a valid tool for early detection of inflammation in humans 27. It requires standardization of cytometer calibration, reagents, storage of samples and protocols, and an excess of antibodies up to saturating conditions, to provide day‐to‐day and laboratory‐to‐laboratory reproducibility.…”

Accelerated wound healing by injectable microporous gel scaffolds assembled from annealed building blocks

“…These results indicated a lower apparent inflammatory response to the MAP scaffolds at Day 1 and are consistent with previous studies demonstrating porous scaffolds allow for better infiltration of inflammatory cells, while non-porous scaffolds result in a barrier to tissue healing and accumulation of inflammatory cells at the wound/scaffold interface 53,54 . After 5 days post-injection, lower fractions of cells staining positive for CD11b, a marker for cells of the myeloid lineage responsible for early tissue inflammation 55,56 , were present both in the surrounding tissue and within the MAP scaffold relative to the non-porous controls (Fig. 6c,d), suggesting a sustained lower inflammatory response 57 , in agreement with what has been observed in other micro-porous scaffolds that are cast ex vivo and implanted in vivo 12 .…”