title: Flow cytometry remission by Ig light chains ratio is a powerful marker of outcome in multiple myeloma after tandem autologous transplant: a real-life study.
abstract: BACKGROUND
  The achievement of complete response (CR) significantly correlates with a better clinical outcome in multiple myeloma (MM) patients treated with autologous stem cell transplant (ASCT). The depth of response is one of the most relevant factors to predict patient's outcome, however the definition of CR through standard criteria has shown several limitations.
  
  
  METHODS
  In this study we evaluated the minimal residual disease (MRD) in 50 consecutive MM patients who underwent an up-front tandem ASCT in our center, using a single-tube six-colors flow cytometry assay (FC) based on intra-cytoplasmic immunoglobulin (cy-Ig) light chains ratio evaluated on patient-specific plasma cells (PC) immune profile, in a real-life setting.
  
  
  RESULTS
  With a sensitivity up to 10(-5), clonal-PC were documented by FC in 36.4% (12/33) of patients in conventional CR after second transplant. The number of flow MRD-negative patients significantly increased after induction and first ASCT, but not between first and second transplant. The 5-years progression-free survival (5ys-PFS) of flow MRD-negative patients after second transplant was significantly better than patients who remained MRD-positive considering both all patients (5ys-PFS: 70% vs 5%) and patients in CR according to standard criteria (5ys-PFS: 67% vs 0%).
  
  
  CONCLUSIONS
  FC remission through cy-Ig light ratio on PC sub-populations is a sensitive, highly informative, low-cost and routinely applicable MRD assay, a powerful tool in treatment response evaluation and a crucial marker of outcome in MM.
authors.affiliation: Clinical Pathology, Regina Elena National Cancer Institute, Rome, Italy. cordone@ifo.it.|Clinical Pathology, Regina Elena National Cancer Institute, Via Elio Chianesi 53, 00144, Rome, Italy. cordone@ifo.it.
authors.forename: Iole
authors.initials: I
authors.lastname: Cordone
authors.affiliation: Hematology and Stem Cell Transplant Unit, Regina Elena National Cancer Institute, Rome, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Marchesi
authors.affiliation: Clinical Pathology, Regina Elena National Cancer Institute, Rome, Italy.
authors.forename: Serena
authors.initials: S
authors.lastname: Masi
authors.affiliation: Clinical Pathology, Regina Elena National Cancer Institute, Rome, Italy.
authors.forename: Valentina
authors.initials: V
authors.lastname: Summa
authors.affiliation: Hematology and Stem Cell Transplant Unit, Regina Elena National Cancer Institute, Rome, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Pisani
authors.affiliation: Clinical Pathology, Regina Elena National Cancer Institute, Rome, Italy.
authors.forename: Roberta
authors.initials: R
authors.lastname: Merola
authors.affiliation: Clinical Pathology, Regina Elena National Cancer Institute, Rome, Italy.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Cigliana
authors.affiliation: Clinical Pathology, Regina Elena National Cancer Institute, Rome, Italy.
authors.forename: Giulia
authors.initials: G
authors.lastname: Orlandi
authors.affiliation: Hematology and Stem Cell Transplant Unit, Regina Elena National Cancer Institute, Rome, Italy.
authors.forename: Svitlana
authors.initials: S
authors.lastname: Gumenyuk
authors.affiliation: Hematology and Stem Cell Transplant Unit, Regina Elena National Cancer Institute, Rome, Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Palombi
authors.affiliation: Hematology and Stem Cell Transplant Unit, Regina Elena National Cancer Institute, Rome, Italy.
authors.forename: Atelda
authors.initials: A
authors.lastname: Romano
authors.affiliation: Hematology and Stem Cell Transplant Unit, Regina Elena National Cancer Institute, Rome, Italy.
authors.forename: Antonio
authors.initials: A
authors.lastname: Spadea
authors.affiliation: Hematology and Stem Cell Transplant Unit, Regina Elena National Cancer Institute, Rome, Italy.
authors.forename: Daniela
authors.initials: D
authors.lastname: Renzi
authors.affiliation: Hematology and Stem Cell Transplant Unit, Regina Elena National Cancer Institute, Rome, Italy.
authors.forename: Elena
authors.initials: E
authors.lastname: Papa
authors.affiliation: Scientific Direction, Regina Elena National Cancer Institute, Rome, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Canfora
authors.affiliation: Clinical Pathology, Regina Elena National Cancer Institute, Rome, Italy.
authors.forename: Laura
authors.initials: L
authors.lastname: Conti
authors.affiliation: Hematology and Stem Cell Transplant Unit, Regina Elena National Cancer Institute, Rome, Italy.
authors.forename: Maria Concetta
authors.initials: MC
authors.lastname: Petti
authors.affiliation: Hematology and Stem Cell Transplant Unit, Regina Elena National Cancer Institute, Rome, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Mengarelli
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D005434:Flow Cytometry / Q000295:instrumentation / Q000379:methods*; D018380:Hematopoietic Stem Cell Transplantation / Q000379:methods*; D006801:Humans; D007147:Immunoglobulin Light Chains / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D009101:Multiple Myeloma / Q000276:immunology* / Q000628:therapy*; D018365:Neoplasm, Residual; D011379:Prognosis; D016019:Survival Analysis; D014182:Transplantation, Autologous / Q000379:methods; D016896:Treatment Outcome
chemical_list: D007147:Immunoglobulin Light Chains
keywords: Autologous stem cell transplant; Flow cytometry remission; Light chains ratio; Minimal residual disease; Multiple myeloma