Introduction
At a Glance Commentary
Sánchez-López V, et al.
Microparticles (MPs) have emerged as promising noninvasive biomarkers for various diseases. Flow cytometry is the most common method to detect MPs, but it is a technical challenge because of the small size of MPs leading to a wide variability in MPs results. A new bead-based standardization tool optimized to specific types of flow cytometers could help circumvent this problem.
We observed high correlations in total MPs and platelet-derived MPs between 2 different cytometers in spite of optimal comparison of absolute MPs numbers remains to be achieved. These results are relevant for further multicenter studies.
Microparticles (MPs) are microvesicles from 0.1 to 1 μm in diameter, which are released from different types of cells during cell activation or apoptotic processes.1, 2 They present cell-specific antigens and cytoplasmic markers and generally express phosphatidylserine on their surface.3, 4 MPs were initially considered to be “cellular dust” without any biological function. They are now, however, of clinical relevance because of their role as vectors and biomarkers for diagnosis or prognosis in vascular damage, blood coagulation, inflammation, angiogenesis, and other pathologic situations.4, 5, 6, 7, 8, 9 Nonetheless, a lack of standardization of the preanalytical and analytical methods has led to a wide variability in the number of MPs detected.10, 11, 12, 13, 14 Flow cytometry is the most common method to detect MPs, which allows the determination of both the number and the cellular origin of MPs based on the antigens presented on their surface. Reliable measurement of MPs by flow cytometry is a technical challenge because of the small size of MPs, which is close to the limit of sensitivity for flow cytometers.15 New sets of fluorescent beads have recently been developed. Megamix-Plus forward scatter channel (FSC) beads (Biocytex, Marseille, France) are designed to obtain the best results using flow cytometers with optimized FSC, such as Beckman Coulter (BC) flow cytometers, whereas Megamix-Plus side scatter channel (SSC) beads (Biocytex, Marseille, France) are more adequate for flow cytometers with optimized SSC, such as Becton Dickinson (BD) flow cytometers. To compare the results between 2 different cytometry platforms (BD and BC flow cytometers), we measured the number of total MPs and platelet-derived MPs (PMPs) in patients with deep venous thrombosis using Megamix-Plus calibration beads.