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High‐sensitive immunophenotyping and DNA ploidy studies for the investigation of minimal residual disease in multiple myeloma
Author(s) -
Almeida Julia,
Orfao Alberto,
Ocqueteau Mauricio,
Mateo Gema,
Corral Mercedes,
Caballero Ma Delores ,
Blade Joan,
Moro Ma Jesus ,
Hernandez Jose,
San Miguel Jesus F.
Publication year - 1999
Publication title -
british journal of haematology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.907
H-Index - 186
eISSN - 1365-2141
pISSN - 0007-1048
DOI - 10.1046/j.1365-2141.1999.01685.x
Subject(s) - immunophenotyping , minimal residual disease , multiple myeloma , cd117 , pathology , medicine , flow cytometry , cd38 , cd34 , bone marrow , immunology , stem cell , cancer research , biology , genetics
Sensitive techniques for monitoring minimal residual disease (MRD) in multiple myeloma (MM) are needed to evaluate the effectiveness of new intensive treatment strategies. The aim of the present study was to explore the applicability and sensitivity of flow cytometry immunophenotyping and DNA ploidy studies for the investigation of residual myelomatous plasma cells (PC) in MM patients. Bone marrow (BM) samples from 61 untreated MM patients were immunophenotypically analysed with a panel of 21 monoclonal antibodies, using a high‐sensitive method based on a two‐step acquisition procedure through a SSC/CD38 +++ ‐CD138 + ‘live‐gate’. Overall, in 87% of MM cases, PC displayed an aberrant phenotype at diagnosis. The most important aberrant criteria were: antigen over‐expression of CD56 (62%), CD28 (16%) and CD33 (6%) and asynchronous expression of CD117 (28%), sIg (21%) and CD20 (10%). DNA aneuploidy was found in 62% of cases. The simultaneous use of these two techniques allowed the detection of aberrant/aneuploid PC in 95% of the cases. Based on dilutional experiments, the detection limit of both techniques ranged from 10 −4 to 10 −5 . In 29 stem cells harvests and 19 BM samples obtained 3 months after autologous transplantation, we have investigated the presence of residual myelomatous PC; they were detected in 44% of the stem cell collections and in 61% of the BM samples obtained after transplant. The percentage of pathological PC did not significantly change during the days of harvest. In summary, the present study shows that the combined use of immunophenotyping and DNA ploidy studies is a suitable approach for MRD investigation in MM patients based on their applicability (95% of cases) and sensitivity (up to 10 −5 ).