Multiparameter Flow Cytometry Identification of Neoplastic Subclones: A New Biomarker in Monoclonal Gammopathy of Undetermined Significance and Multiple Myeloma.

Multiparameter flow cytometry (MFC)-based clonality assessment is a powerful method of diagnosis and follow-up in monoclonal gammopathy of undetermined significance (MGUS) and multiple myeloma (MM). However, the relevance of intraclonal heterogeneity in immunophenotypic studies remains poorly understood. The main objective of this work was to characterize the different immunophenotypic subclones in MGUS and MM patients and to investigate their correlation with disease stages. An 8-color MFC protocol with 17 markers was used to identify the subclones within the neoplastic compartment of 56 MGUS subjects, 151 newly diagnosed MM patients, 30 MM subjects in complete remission with detectable minimal residual disease, and 36 relapsed/refractory MM patients. Two or more clusters were observed in > 85% of MGUS subjects, 75% of stage I MM patients, and < 15% in stage III. Likewise, a significant correlation between the dominant subclone size, secondary cytogenetic features, and changes in the expression of CD27, CD44, and CD81 was detected. The loss of intraclonal equilibrium may be an important factor related with kinetics and risk of progression not well considered to date in MFC studies. The MFC strategy used in this work can provide useful biomarkers in MGUS and MM.

Comparison and cost analysis of three protocols for mobilization and apheresis of haematopoietic progenitor cells.

INTRODUCTION: Autologous bone marrow transplantation is a component of the malignant hemopathy therapy. The preferred mobilization and collection method is apheresis. The aim of this study is to compare three protocols analyzing the effect of plerixafor, higher dose of G-CSF and large volume leukapheresis (LVL). MATERIALS AND METHODS: A retrospective cohort study including 119 patients referred for mobilization. Three protocols were compared: (a) G-CSF 10 µg/kg/day subcutaneous (sc) × 4 days mobilizing 1 to 1.5 blood volumes. (b) G-CSF 10 µg/kg/day sc × 4 days + plerixafor 0.24 mg/kg/day sc preventively or as a rescue agent mobilizing 1 to 1.5 blood volumes. (c) G-CSF 20 µg/kg/day sc × 4 days ± plerixafor 0.24 mg/kg/day sc preventively or as a rescue agent mobilizing 3 to 4 blood volumes. RESULTS: The average number of days of apheresis was reduced to 1.37 with protocol 3. The average cost per patient was reduced by 67% compared with protocol 2 and increased by only 5% compared with protocol 1, reducing the failure rate to 0%. CONCLUSION: Adding preemptive or rescue plerixafor (protocol 2) to G-CSF 10 µg/kg/day alone (protocol 1) did not improve the days of apheresis nor the number of CD34+ cells collected but had higher cost and failure rate. Using LVL, plerixafor and G-CSF 20 µg/kg/day (protocol 3) decreased the number of sessions to 1.37, reduced the failure rate to 0% and led to a significant increase in the number of CD34+ cells collected without toxicity and with a similar cost to protocol 1.

Spontaneous Regression of Primary Thyroid Lymphoma: Two Rarities at the Same Time.

Primary thyroid lymphomas are pretty uncommon, and constitute about 5% of the neoplasms of this organ. Spontaneous tumor regression is defined as the total or partial disappearance of a tumor as proven by microscope without treatment or under inadequate treatment. It is estimated to happen in one out of 60,000-100,000 cases. We present a case of primary thyroid lymphoma with spontaneous regression after diagnostic puncture and corroborated with hemithyroidectomy at four months. The patient died after twenty-six months of follow-up because of endocarditis and there was no relapse at any time.

A Rare Case of Pure Erythroid Sarcoma in a Pediatric Patient: Case Report and Literature Review.

We describe an exceptional case of erythroid sarcoma in a pediatric patient as a growing orbital mass with no evidence of morphologic bone marrow involvement, who was finally diagnosed of pure erythroid sarcoma based on histopathology and flow cytometry criteria. We discuss the contribution of standardized eight-color flow cytometry as a rapid and reliable diagnostic method. The use of normal bone marrow databases allowed us to identify small aberrant populations in bone marrow and later confirm the diagnosis in the neoplastic tissue.