Cytométrie et ses applications en immunologie clinique

Cytometry (cyto = cell; metry = measuring) consist in an objective, quantitative and multiparametric analysis of cells. It is based on fluorescence, fluidic and optical tools with the help of signal or image computer treatment. It is a high performance system allowing simultaneous analysis of 4, 6, 8 or more parameters, at very high speed from 500 to 10 000 cells per second. Image cytometry is largely used in research. In medical analysis, Flow-cytometry is more and more used for leukaemia typing, lymphocyte counting, among them HIV monitoring or immunological treatments follow-up. Identification of numerous cell subtypes and their activation, maturation or proliferation status is now possible. Its high precision and wide use have lead to the description of new cell subtypes (e.g. gamma delta, mucosal, T.NK or regulatory T cells…) that have targeted activity. Recently, oligoclonal clonopathies of undetermined significance but with risks for pathological development have been described. Proliferative or heteroploidy disorders can also be evaluated. Applications in solid tumor and microbiology are under development. In conclusion, the major point of cytometry is to bring tools to approach cell populations in their diversity and complexity. It would be ridiculous today to consider them as homogeneous, uniform systems. In other words, cell « sociology » is a wide new field that remains to be explored.