IgM multiple myeloma with an extremely rare non-aggressive presentation: A case report.

In the present study, the case of a 41-year-old man with immunoglobulin (Ig)M multiple myeloma (MM) that presented with an unusually non-aggressive clinical course who has survived for >9 years to date, is presented. Initial diagnosis of symptomatic MM was established according to the International Myeloma Working Group consensus statement and guidelines. Due to the mild symptoms, no therapy was administered and the patient was closely followed up. Eight years after initial diagnosis, clinical, morphological and genetic progression occurred with the development of hypercalcemia, progressively deteriorating polyneuropathy, clonal expansion of plasma cells up to 50% of hematopoietic cells and demonstration of the typical t(11;14) translocation (Ig heavy chain locus rearrangement). Subsequently, 4 cycles of induction chemotherapy with velcade, cyclophosphamide and dexamethasone, were administered. At the time of writing, the patient remained alive in generally good health. To the best of our knowledge, with a survival time of >9 years, this case reports the longest survival time of an IgM MM patient to date, which contradicts previous evidence that suggests IgM MM exhibits an aggressive clinical course.

Phenotypic and functional analysis of human fetal liver hematopoietic stem cells in culture.

Steady-state hematopoiesis and hematopoietic transplantation rely on the unique potential of stem cells to undergo both self-renewal and multilineage differentiation. Fetal liver (FL) represents a promising alternative source of hematopoietic stem cells (HSCs), but limited by the total cell number obtained in a typical harvest. We reported that human FL nonobese diabetic/severe combined immunodeficient (NOD/SCID) repopulating cells (SRCs) could be expanded under simple stroma-free culture conditions. Here, we sought to further characterize FL HSC/SRCs phenotypically and functionally before and following culture. Unexpanded or cultured FL cell suspensions were separated into various subpopulations. These were tested for long-term culture potential and for in vivo repopulating function following transplantation into NOD/SCID mice. We found that upon culture of human FL cells, a tight association between classical stem cell phenotypes, such as CD34(+) /CD38(-) and/or side population, and NOD/SCID repopulating function was lost, as observed with other sources. Although SRC activity before and following culture consistently correlated with the presence of a CD34(+) cell population, we provide evidence that, contrary to umbilical cord blood and adult sources, stem cells present in both CD34(+) and CD34(-) FL populations can sustain long-term hematopoietic cultures. Furthermore, upon additional culture, CD34-depleted cell suspensions, devoid of SRCs, regenerated a population of CD34(+) cells possessing SRC function. Our studies suggest that compared to neonatal and adult sources, the phenotypical characteristics of putative human FL HSCs may be less strictly defined, and reinforce the accumulated evidence that human FL represents a unique, valuable alternative and highly proliferative source of HSCs for clinical applications.

Long-term expansion of transplantable human fetal liver hematopoietic stem cells.

Hematopoietic stem cells (HSCs), with their dual ability for self-renewal and multilineage differentiation, constitute an essential component of hematopoietic transplantations. Human fetal liver (FL) represents a promising alternative HSC source, and we previously reported simple culture conditions allowing long-term expansion of FL hematopoietic progenitors. In the present study, we used the nonobese diabetic/severe combined immunodeficiency (NOD/SCID) mouse xenotransplantation assay to confirm that human FL is rich in NOD/SCID-repopulating cells (SRCs) and to show that these culture conditions repeatedly maintained short- and long-term SRCs from various FL samples for at least 28 days. Quantitative limited dilution analysis in NOD/SCID mice demonstrated for the first time that a 10- to over a 100-fold net expansion of FL SRCs could be achieved after 28 days of culture. The efficiency of this culture system may lead to an increase in the use of FL as a source of HSCs for transplantation in adult patients, as previously demonstrated with umbilical cord blood under different culture conditions.

The role of interleukin 13 in classical Hodgkin lymphoma.

The Reed-Sternberg (RS) cells of classical Hodgkin lymphoma (cHL) produce several cytokines, which are thought to account for the unique clinical and pathologic features of this disease. We previously identified interleukin (IL)-13 expression as a common feature of cHL and have studied the potential role of this cytokine as an autocrine growth factor for RS cells. IL-13 and the IL-13-specific receptor chain (IL-13R alpha1) are frequently expressed in cHL-derived cell lines and in RS cells from biopsies of cHL tissues. In contrast, IL-13 expression in non-Hodgkin lymphoma (NHL) is uncommon. Neutralization of IL-13 in cultures of cHL-derived cell lines HDLM-2 and L-1236 leads to a dose-dependent inhibition of proliferation, and is associated with increased apoptosis in L-1236 cells. IL-13 neutralization also decreased activation of signal transducer and activator of transcription (STAT)6, an important mediator of IL-13 function. Moreover, STAT6 is often activated in RS cells from primary tumor samples, implying that IL-13 signaling is occurring in these cells in vivo. This review will describe the biologic activities of IL-13 in the immune system, and summarize the evidence implicating IL-13 as an autocrine growth factor for RS cells in cHL. Finally, we will discuss the potential influence of IL-13 on the reactive inflammatory infiltrate that is characteristic of cHL.

Characterization of a novel human anaplastic large cell lymphoma cell line tumorigenic in SCID mice.

L82, a novel anaplastic large cell lymphoma (ALCL) cell line was established from the pleural effusion of a 24-year-old patient with recurrent ALCL. L82 cells showed the typical morphologic features of ALCL cells with irregular, often indented, nuclear profiles, prominent nucleoli, and abundant cytoplasm. The immunoprofile of L82 corresponds to that seen typically in primary ALCL cells, with positivity for CD30, EMA, CD3, CD4, CD25, CD71, TIA1, and granzyme B; the cells were negative for EBV-related antigens. Cytogenetic analysis showed a complex, near triploid karyotype with 72-77 chromosomes, including the ALCL specific translocation t(2;5)(p23;q35). Chromosomal analysis revealed a number of secondary structural alterations including amplification of 7q21-31, 1q, and 6p, and gain of chromosomal material in 8q (affecting the c-myc gene). The rearrangement of the T-cell receptor-gamma locus shows that L82 is clonally derived from T-lineage lymphoid cells. mRNAs for interleukin 7 (IL-7), IL-8, IL-9, IL-10, TNF-beta, and for the IL-7 and IL-9 receptor were found. These data show that the T-helper cell (Th)1/Th2 balance was polarized to Th2. L82 were inoculated intraperitoneally into 4 week-old SCID mice and produced a disseminated tumor within 4-6 weeks. Morphological, immunohistochemical, and molecular genetic investigation confirmed that the xenograft and the original ALCL tumor were identical. SCID mice xenografted with the human ALCL cell line, L82, provide a useful model system for the investigation of the biology of ALCL and of new therapeutic approaches, such as specific immunotherapy.

Signal transducer and activator of transcription 6 is frequently activated in Hodgkin and Reed-Sternberg cells of Hodgkin lymphoma.

The unique clinicopathologic features of Hodgkin lymphoma (HL) are due to the multiple cytokines produced by its neoplastic cells, the Hodgkin and Reed-Sternberg (HRS) cells. Cytokine signaling is mediated through the signal transducer and activator of transcription (STAT) family of transcription factors. Immunoblotting and immunohistochemistry were used to examine cell lines and tissue sections derived from patients with HL and non-Hodgkin lymphoma (NHL) for expression of activated STAT proteins. Constitutive phosphorylation of STAT6 and STAT3 was common in HL. STAT6 was constitutively phosphorylated in 5 of 5 HL cell lines and in HRS cells from 25 of 32 (78%) classical HL cases. STAT3 was constitutively phosphorylated in 4 of 5 HL cell lines and in HRS cells from 27 of 31 (87%) classical HL cases. Only 4 of 24 NHL cases demonstrated constitutive STAT6 activation, whereas STAT3 activation was observed in 6 of 13 (46%) cases of B-cell NHL and 8 of 11 (73%) cases of T-cell NHL. Constitutive STAT5 phosphorylation was not a common feature of HL or NHL. STAT6 mediates signaling by interleukin 13 (IL-13), a cytokine frequently expressed by HRS cells. Antibody-mediated neutralization of IL-13 resulted in significant decreases in both cellular proliferation and levels of phosphorylated STAT6 of HL cell lines. In conclusion, constitutive STAT6 phosphorylation is a common and distinctive feature of HRS cells in classical HL, whereas STAT3 activation was regularly present in both HL and NHL. These results suggest that IL-13 signaling is largely responsible for the constitutive STAT6 activation observed in HRS cells and further implicate IL-13 as an important growth factor in classical HL.