Myelomatous plasma cells show a high heterogeneity both in their immunophenotypic characteristics as well as in their cytogenetic features. Thus far, no extensive studies have been carried out to explore whether such antigenic diversity is associated with specific genetic characteristics.We have investigated the relationship between the immunophenotypic profile at plasma cell and both their DNA ploidy status (evaluated by flow cytometry) and specific genetic features (ascertained by fluorescence in situ hybridization) in a large series of 915 patients with newly diagnosed multiple myeloma. The non-hyperdiploid multiple myeloma group (n = 454, 52%) was associated with a significantly higher frequency of positivity for CD28 and CD20 as well as a higher incidence of CD56 À and CD117À cases (P < 0.001). Remarkably, 13q deletion and immunoglobulin heavy chain (IGH) gene rearrangements, which were significantly more common in non-hyperdiploid multiple myeloma, showed a strong association with CD117 À cases. IGH translocation to 11q13 was associated with reactivity for CD20 (P < 0.001), downregulation of CD56 (P < 0.001), and lack of expression of CD117 (P = 0.001). By contrast, IGH translocations to other chromosome partners were almost exclusively found among CD20 À and CD117 À cases (P < 0.001). These results suggest that genetic categories in multiple myeloma exhibit particular immunophenotypic profiles which in turn are strongly associated with the DNA ploidy status.

on behalf of the GEM (Grupo Españ ol de Mieloma)/PETHEMA (Programa para el Estudio de la Terapé utica en Hemopatías Malignas) cooperative study groupsThe presence of CD19 in myelomatous plasma cells (MM-PCs) correlates with adverse prognosis in multiple myeloma (MM). Although CD19 expression is upregulated by CD81, this marker has been poorly investigated and its prognostic value in MM remains unknown. We have analyzed CD81 expression by multiparameter flow cytometry in MM-PCs from 230 MM patients at diagnosis included in the Grupo Españ ol de Mieloma (GEM)05465years trial as well as 56 high-risk smoldering MM (SMM). CD81 expression was detected in 45% (103/230) MM patients, and the detection of CD81 þ MM-PC was an independent prognostic factor for progression-free (hazard ratio ¼ 1.9; P ¼ 0.003) and overall survival (hazard ratio ¼ 2.0; P ¼ 0.02); this adverse impact was validated in an additional series of 325 transplant-candidate MM patients included in the GEM05 o65 years trial. Moreover, CD81þ SMM (n ¼ 34/56, 57%) patients had a shorter time to progression to MM (P ¼ 0.02). Overall, our results show that CD81 may have a relevant role in MM pathogenesis and represent a novel adverse prognostic marker in myeloma.

cooperative study group Achieving complete remission (CR) in multiple myeloma (MM) translates into extended survival, but two subgroups of patients fall outside this paradigm: cases with unsustained CR, and patients that do not achieve CR but return into a monoclonal gammopathy of undetermined significance (MGUS)-like status with long-term survival. Here, we describe a novel automated flow cytometric classification focused on the analysis of the plasma-cell compartment to identify among newly diagnosed symptomatic MM patients (N ¼ 698) cases with a baseline MGUS-like profile, by comparing them to MGUS (N ¼ 497) patients and validating the classification model in 114 smoldering MM patients. Overall, 59 symptomatic MM patients (8%) showed an MGUS-like profile. Despite achieving similar CR rates after high-dose therapy/autologous stem cell transplantation vs other MM patients, MGUS-like cases had unprecedented longer time-to-progression (TTP) and overall survival (OS; B60% at 10 years; Po0.001). Importantly, MGUS-like MM patients failing to achieve CR showed similar TTP (P ¼ 0.81) and OS (P ¼ 0.24) vs cases attaining CR. This automated classification also identified MGUS patients with shorter TTP (P ¼ 0.001, hazard ratio: 5.53) and ultra-high-risk smoldering MM (median TTP, 15 months). In summary, we have developed a biomarker that identifies a subset of symptomatic MM patients with an occult MGUS-like signature and an excellent outcome, independently of the depth of response.

Umbilical cord blood transplantation (UCBT) has been used increasingly in both pediatric and adult patients. The total nucleated cell (NC) dose infused is the most critical factor in determining speed of engraftment and survival. Using standard collection techniques, the mean NC content of UCB units is about 10 × 10 8, and only 25% of these units reach the target cell dose of 2 × 10 7 /kg in UCBT patients weighing 50-70 kg. We have designed a modified placental/umbilical two-step collection method in which a standard blood fraction obtained by umbilical venipuncture is combined with a second fraction harvested after placental perfusion with 50 ml heparinized 0.9% saline. This second fraction contributed 32% volume and 15% NCs to the whole UCB unit (123.7 ± 50.1 ml and 1.26 ± 0.52 × 10 9 NC). The proportion of progenitor cells in both fractions was not significantly different, indicating that the hematopoietic potential of these larger units is 20% (range, 2%-100%) higher than UCB units collected by standard methods. In addition, the bacterial contamination rate associated with this novel collection method (2.78%) compares favorably. Since 1998 we have further enriched our units by processing only UCB units over 0.8 × 10 9 NCs, resulting in a 36% cell increment (1.46 ± 0.52 × 10 9 NCs). Thus, 84% and 54% of the Madrid UCB Bank inventory would fulfill the target cell dose of 2 × 10 7 /kg in patients weighing 50 and 65 kg, respectively. This significant UCB banking improvement gives larger pediatric and adult patients a greater chance of finding adequate grafts in order to achieve better clinical outcomes after UCBT. Stem Cells 2005;23:324-334

The standardization of CD34+ cell enumeration by flow cytometry is strongly reliant on a consistent initial cell acquisition procedure. The interlaboratory variation can be minimized by using frozen cell aliquots as reference samples. Both requisites should be considered for CD34 testing and UCB unit selection by regulatory institutions involved with cord blood banking and transplantation.