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AC133 is a molecule whose expression in the human hematopoietic system is restricted to a subset of CD34+ progenitor/stem cells with long-term repopulating ability. The antigenic features of these cells, like CD34+ cells, are described heterogeneous. The immunophenotypic profile of AC133+ cells, detected by means of dual-color flow cytometry, in bone marrow (BM), cytokine-mobilized peripheral blood (PB) and umbilical cord blood (UCB) was evaluated. The highest percentage of AC133+ cells was detected in mobilized PB despite not significantly different from that found in BM, but both are higher than that found in UCB. In addition, the highest percentage of CD34, HLA-DR and CD33 co-expressing AC133+ cells was observed in mobilized PB. Furthermore, UCB was found to be enriched in CD7+ and CD19+ cells and BM was found to be enriched in AC133+ cells co-expressing CDw90 and CD71. Our data confirm the immunophenotypic heterogeneity of cells expressing AC133 antigen, a promising new stem cell marker to be increasingly used as additional target for alternative identification and separation of early hematopoietic cells.

Normal promyelocytes express CD45RO, while acute promyelocytic leukemia (APL) blasts express CD45RA, both isoforms of common leukocyte antigen with mutually exclusive expression. Here we report a patient with accumulation of promyelocytes in the bone marrow and the diagnostic strategy is described along with the ability to quickly discriminate between normal and abnormal cells using the flow cytometric detection of expression of RA/RO isoforms of CD45.

Despite recent therapeutic advances, primary central nervous system lymphoma (PCNSL) shows the worst prognosis among all non-Hodgkin lymphomas (NHLs), with a 5-year survival rate ranging from 4 to ...

Clinical and biological parameters were retrospectively reviewed in 34 cases of T-lineage acute lymphoblastic leukemia (T-ALL), classified as "early" (20 cases) or "late" (14 cases) subgroups, according to the degree of blast cell differentiation, assessed by immunophenotyping. In "early" T-ALL, age, co-expression of "immature" (CD34 and HLA-Dr) or myeloid (My+) antigens, proliferative activity (as evaluated by Ki67 monoclonal antibody), and expression of the "multidrug-resistance" (MDR) phenotype (as determined by C-219 monoclonal antibody) were significantly higher, while WBC count and expression of CDl0 were significantly lower, than in "late" T-ALL. Furthermore, although no statistically significant difference was found between the two groups, "late" T-ALL more frequently displayed a greater extramedullary tumor mass ("lymphoma-like" syndrome), LI FAB morphology and a normal karyotype. A single patient, with "late" T-ALL, also showed positivity for TCR gamma/delta chains, specific monoclonal antibodies. On the whole, 30 patients (88.2%) achieved complete remission: 16(80%) were "early" and 14(100%) "late" T-ALL. No statistical difference was found between the two groups with respect to disease free survival (42% vs 54% at six years), whereas median overall survival was significantly shorter in "early" T-ALL (23 months vs median not yet reached at six years for "late" T-ALL, p0.05). We conclude that "early" and "late" T-ALL show clinical and biological differences, that could perhaps justify differential therapeutic approaches.

We report an episode of severe bradycardia that occurred in a 49-year-old woman with fever and malignant jaundice during antibiotic therapy with linezolid, a new oxazolidinone with activity against Gram-positive cocci. In our case, the strict temporal dependence between bradycardia and linezolid therapy seems to provide strong evidence for a causal relationship. To our knowledge, this is the first report of linezolid-induced bradycardia. This adverse event confirms that the new antibiotic linezolid should be administered with caution in patient with jaundice and hepatic insufficiency.

(2003). Late and Long-lasting Response in an Adult Chronic Idiopathic Thrombocytopenic Purpura after Extended Course of Rituximab. Leukemia & Lymphoma: Vol. 44, No. 3, pp. 561-562.