Scientific comment on: “Quantitative flow cytometric evaluation of CD200, CD123, CD43 and CD52 as a tool for the differential diagnosis of mature B-cell neoplasms”☆

cell or directly of the antibody binding capacity using standard 2 ince the 1980s, multiparametric flow cytometry (FCM) was rought to the clinical laboratory for diagnostic immunopheotyping. The expression of antibodies bound to the embrane or intracellular receptors has been generally efined as positive or negative with a cutoff set relative to a onstaining control population. It is known that the intenity of the fluorescent signal is proportional to the amount f antibody bound per cell, i.e., it is proportional to the numer of antigen sites expressed. This means that the quantity of olecules per cell can be measured by the intensity of antigen xpression. One of the most important clinical utilities of fluorescence ntensity measurements is the diagnosis of hematological alignancies, by which aberrant phenotypes are identified ccording to the overor under-expression of various cellular roteins compared to those expressed in normal cells. In principle, antigen detection by FCM is described qualitaively as having absent, bright or dim expressions. Advances ver the past two decades have resulted in the development f FCM methods and materials that permit measurements f quantitative fluorescence with improved levels of control nd interlaboratory precision. With these advances, interst in quantitative flow cytometry (QFCM) has grown as a