Issue highlights-may 2012

The paper in this issue by Johnsen et al, Clinical impact of leukemic blast heterogeneity at diagnosis in cytogenetic intermediate-risk acute myeloid leukaemia,’’ deals with an important issue that is central to the role played by persistent leukemic cells in acute myeloid leukemia. Specifically, the heterogeneity of leukemic blasts is thought to have significant relationship to the prognosis of the disease; this is demonstrated by numerous studies recently published in our journal at the cytogenetic and molecular level as well as by documented immunophenotypic variations found in the malignant cells.Johnsen’s paper demon- strates that leukemic cancer stem cells share surface molecules in common with normal stem cells, and both cell types are characterized by high self-renewal and plu- ripotency. The persistence of leukemic cancer stem cells is considered to be essential in the maintenance of acute myeloid leukemia and its relapse. Recent advances in this area focus on the development of new drugs to eradicate leukemic stem cells responsible for sustaining leukemic growth

Prethymic cytoplasmic CD3 negative acute lymphoblastic leukemia or acute undifferentiated leukemia: a case report

Acute undiffentiated leukemia (AUL) is an acute leukemia with no more than one membrane marker of any given lineage. Blasts often express HLA-DR, CD34, and/or CD38 and may be positive for terminal deoxynucleotidyl transferase (TdT). The expression of CD34, HLA-DR, and CD38 has been shown in pro-T-ALL, although in this case, blasts should also express CD7 and cyCD3. However, some cases of T-ALL without CD3 in the cytoplasm and all TCR chain genes in germ line configuration are reported, features that fit well with a very early hematopoietic cell. We report a case of acute leukemia CD34+/-HLADR+CD7+CD38+cyCD3- in which a diagnosis of AUL was considered. However the blasts were also positive for CD99 and TCR delta gene rearrangement which was found on molecular studies. Therefore a differential diagnosis between AUL and an early cyCD3 negative T-ALL was debated

The role of CD19 and CD27 in the diagnosis of Multiple Myeloma by Flow Cytometry: a new statistical model.

We have developed a new statistical diagnostic model that examines the correlation between immunophenotype and clonality as detected by flow cytometry (FC) and histology, defining the diagnostic role of FC in multiple myeloma (MM). The 192 bone marrow samples from patients and control subjects were studied for routine diagnostic analysis of MM; a minimum of 100 plasma cells (PCs) were analyzed for each patient sample. A direct 7- or 8-color method was applied to study the immunophenotype of PCs, utilizing a FACSCanto II (BD Biosciences, San Jose, CA). Samples were labeled with fluorochrome-conjugated monoclonal antibodies (AmCyan, Pac Blue, fluorescein isothiocyanate, phycoerythrin [PE], PECy7, peridinin-chlorophyll protein, allophycocyanin [APC], and APC-Cy7) to the following antigens: CD138, CD81, CD200, CD221, CD45, CD38, CD28, CD19, CD27, CD117, CD38, CD33, CD20, CD56, CD10, and immunoglobulin κ and λ light chains. Among all antigens tested, CD19 and CD27, when applied to our model, resulted in optimal concordance with histology. This model defines the effective diagnostic role FC could have in MM and in the detection of minimal residual disease

Multiparameter immunophenotyping by flow cytometry in multiple myeloma. The diagnostic utility of defining ranges of normal antigenic expression in comparison to histology

BACKGROUND: Numerous studies have reported on the immunophenotype of plasma cells (PCs) in monoclonal gammopathy of undetermined significance (MGUS) and in plasma cell myeloma (PCM), but very few have examined the immunophenotype of normal PCs. In this study, an objective definition of normal range of expression for each antigen was found on normal control PCs. Using these new ranges of normal expression (new method) is different from using a static 20% of PCs cut-off for all antigens as described in the literature (traditional method). These newly calculated normal ranges for each antigen were applied to our data, and compared to histologic and immunohistochemical findings. METHODS: Bone marrow samples from 46 patients with PC neoplasms and 15 normal controls were studied. A minimum of 100 PC were analyzed for each patient and control sample. An 8-color staining method was applied to study the immunophenotype of PCs, using a BD FACSCanto II. RESULTS: By the new ranges of normality calculated in this study it was determined that different antigens have different level of expression on polyclonal PCs. CD19 correlated with histology by both the traditional and new methods, but had superior correlation by the new method. CONCLUSIONS: This report is the first 8-color immunophenotypic study of PCM in which a "range of normal expression" for each antigen is defined. This is a critical step to help distinguish between a normal and neoplastic PC immunophenotype and discern which antigens are of diagnostic importance

Normal ovarian surface epithelial label-retaining cells exhibit stem/progenitor cell characteristics

Ovulation induces cyclic rupture and regenerative repair of the ovarian coelomic epithelium. This process of repeated disruption and repair accompanied by complex remodeling typifies a somatic stem/progenitor cell-mediated process. Using BrdU incorporation and doxycycline inducible histone2B-green fluorescent protein pulse–chase techniques, we identify a label-retaining cell population in the coelomic epithelium of the adult mouse ovary as candidate somatic stem/progenitor cells. The identified population exhibits quiescence with asymmetric label retention, functional response to estrous cycling in vivo by proliferation, enhanced growth characteristics by in vitro colony formation, and cytoprotective mechanisms by enrichment for the side population. Together, these characteristics identify the label-retaining cell population as a candidate for the putative somatic stem/progenitor cells of the coelomic epithelium of the mouse ovary