FLOW CYTOMETRY IN IMMUNOLOGY AND HEMATOLOGY 

Minerva Biotecnologica 1999 June;11(2):139-52

Copyright © 1999 EDIZIONI MINERVA MEDICA

language: English

The immunophenotyping of acute leukemias

Basso G.

Dipartimento di Scienze Pediatriche e dell’Adolescenza, Università degli Studi,Torino, Italy

The immu­no­phen­o­typ­ing of ­acute leu­ke­mi­as is ­today the pre­ferred meth­od for per­form­ing the iden­tifi­ca­tion, enu­mer­a­tion and char­ac­ter­iza­tion of ­blast ­cells at diag­no­sis. In ­spite of its wide­spread ­present util­iza­tion, ­there ­does not ­exist a stan­dard­ized pro­to­col in clin­i­cal labor­a­to­ries to ­achieve ­inter-labor­a­to­ry repro­du­cibil­ity ­using the ­most infor­ma­tive pro­ce­dures. The com­plex­ity of ­most com­mon ques­tions in ­acute leu­ke­mia immu­no­phen­o­typ­ing, diag­no­sis and eval­u­a­tion of min­i­mal resid­u­al dis­ease, ­demands the util­iza­tion of the major­ity of pos­sible infor­ma­tion. The mul­ti­par­a­met­ric immu­no­phen­o­typ­ing ­approach ­using ­three col­ors simul­ta­ne­ous­ly is report­ed ­here. This ­approach is ­based on an ade­quate ­choice of ­reagents, and on sam­ple prep­ar­a­tion ­using ­whole ­blood. Recent ­data ­show ­that ­three col­or anal­y­sis is an ade­quate meth­od to ­achieve a ­clear dis­crim­i­na­tion ­between nor­mal and path­o­log­i­cal ­cells, in ­order to per­form the diag­no­sis, clas­sifi­ca­tion and prog­no­sis of ­acute leu­ke­mi­as. One col­or is ­used for the immu­no­log­i­cal ­gate, in ­fact ­this is the ­best meth­od for the leu­kem­ic ­cell iden­tifi­ca­tion, and the fol­low­ing anal­y­sis is per­formed in ­blast-gat­ed bipar­a­met­ric his­to­grams. The pro­ce­dure ­must be dis­sim­i­lar in lym­pho­blas­tic and myel­o­blas­tic leu­ke­mi­as, ­because the diag­nos­tic ques­tions are dif­fer­ent for het­ero­ge­ne­ity and clo­nal­ity of malig­nant ­cells. The use­ful meth­od to ­define pos­i­tive anti­gen cri­te­ria is the quan­tifi­ca­tion of anti­gens, ­using pre-cal­i­brat­ed ­sets of flu­o­res­cent ­beads. This meth­od per­mits a ­cross eval­u­a­tion of immu­no­phen­o­typ­ing ­results ­between dif­fer­ent inves­ti­ga­tors and labor­a­to­ries. Recent ­reports indi­cate ­that the phe­no­typ­ic aber­ra­tions ­reflect genet­ic abnor­mal­ities of leu­kem­ic ­cells and there­fore ­their def­i­ni­tion and iden­tifi­ca­tion ­seem rel­e­vant for prog­nos­tic impli­ca­tions and for min­i­mal resid­u­al dis­ease iden­tifi­ca­tion.