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Jan Cerny

Publications and source records attributed to Jan Cerny.

27 records · Page 2Linked to original sources
PubMed2003

Unusual sequence of VDJ rearrangement revealed by molecular analysis in a patient with indolent lymphoma.

We report a unique case of indolent lymphoma with an unusual VDJ rearrangement. Polymerase chain reaction (PCR) analysis of bone marrow at the time of diagnosis was positive for both BCL-2/JH and CDRIII rearrangements. After treatment, the patient achieved complete remission (CR) with slow disappearance of both rearrangements (CDRIII and then BCL-2/JH). Subsequently, two new CDRIII rearrangements were detected in bone marrow, peripheral blood, and lymph node tissue. After this conversion, fluorescent activated cell sorting (FACS) analysis demonstrated monoclonal disease, suggesting that both CDRIII rearrangements originated from one cell. Histological evidence of a B-cell small lymphocytic lymphoma (B-SLL) infiltrate in the bone marrow became evident approximately 1 year after the two CDRIII rearrangements appeared. Direct sequencing revealed that one of the CDRIII sequences consisted of a VDVDJ rearrangement. This is the first report of such a rearrangement in a case of indolent lymphoma. This type of rearrangement has been described to result from a secondary VDJ recombination in childhood acute lymphoblastic leukemia (ALL) leading towards oligoclonality and poorer prognosis. Our observations suggest that such a finding in an indolent lymphoma patient may precede transformation into an aggressive disease. Early detection by PCR could have substantial impact on the prognosis of such patients.

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PubMed2003

Familial chronic lymphocytic leukemia.

Familial aggregation of chronic lymphocytic leukemia (CLL) has been observed more frequently than familial aggregation of any other type of oncohematologic disorder. The presence of cells with a CLL-like immunophenotype (CLL-like cells) was recently documented in 13.5% healthy first-degree relatives of CLL patients. We present a family with CLL in which 2 brothers, a sister and their mother were affected.

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PubMed2002

Repertoire of antibody response in bone marrow and the memory response are differentially affected in aging mice.

The primary burst of Ab and germinal center (GC) formation in response to T-dependent Ag is compromised in aging mice. Here we examine the effects of aging on the post-GC phase of memory B cell differentiation and the late Ab repertoire maturation in bone marrow (BM) in mice immunized with a hapten nitrophenyl coupled to chicken gamma-globulin. Specific Ab-forming cells (AFC) with mutated V(H) genes accumulated preferentially in the BM of aged mice, although the AFC numbers and average number of mutations per V(H) were lower, and the D gene usage was less restricted compared with those in the young animals. However, the repertoire of AFC after an Ag boost demonstrated the hallmarks of Ag selection, including the recurrent mutations and canonical VD rearrangements, similar to the late primary response in young animals. It is postulated that the Ab repertoire maturation in aged mice is delayed and may be notably improved by repeated immunizations.

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PubMed2002

T-cell engagement of dendritic cells rapidly rearranges MHC class II transport.

Assembly of major histocompatibility complex (MHC) molecules, which present antigen in the form of short peptides to T lymphocytes, occurs in the endoplasmic reticulum; once assembled, these molecules travel from the endoplasmic reticulum to their final destination. MHC class II molecules follow a route that takes them by means of the endocytic pathway, where they acquire peptide, to the cell surface. The transport of MHC class II molecules in 'professional' antigen-presenting cells (APCs) is subject to tight control and responds to inflammatory stimuli such as lipopolysaccharide. To study class II transport in live APCs, we replaced the mouse MHC class II gene with a version that codes for a class II molecule tagged with enhanced green fluorescent protein (EGFP). The resulting mice are immunologically indistinguishable from wild type. In bone-marrow-derived dendritic cells, we observed class II molecules in late endocytic structures with transport patterns similar to those in Langerhans cells observed in situ. We show that tubular endosomes extend intracellularly and polarize towards the interacting T cell, but only when antigen-laden dendritic cells encounter T cells of the appropriate specificity. We propose that such tubulation serves to facilitate the ensuing T-cell response.

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PubMed2002

Homing of purified murine lymphohematopoietic stem cells: a cytokine-induced defect.

This study was designed to establish a direct homing assay using purified lineage-negative Sca-1-positive (Lin(-) Sca(+)) murine bone marrow cells and to evaluate the effects of cytokines on homing. C57BL/6 Lin(-) Sca(+) marrow stem cells were labeled with 5-(and 6)-carboxyfluorescein diacetate succinimidyl ester (CFDA-SE) and then injected by tail vein into untreated C57BL/6 mice. Marrow was harvested at various times after cell infusion and analyzed on a high-speed MoFlo cell sorter for fluorescent positive events, using a large event analysis, with at least 16 million total events analyzed. We have shown that homing of Lin(-) Sca(+) cells plateaus by 1 h, and at 3 h post-infusion is linear between 50,000 and 1,000,000 infused cells. This forms a base for a homing assay in which 250,000 CFDA-SE labeled Lin(-) Sca(+) marrow cells are infused and then recovered from marrow 3 h later, followed by a large-event fluorescence-activated cell sorting (FACS) analysis. We found that 7.45-9.32% of infused cells homed and that homing of stem cells cultured for 48 h in interleukin-3 (IL-3), IL-6, IL-11, and steel factor cultured cells was defective when compared to noncultured cells. Exposure of marrow stem cells to IL-3, IL-6, IL-11, and steel factor induces a stem cell homing defect, which probably underlies the engraftment defect previously characterized under these conditions.

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PubMed2002

Engraftment of post 5-fluorouracil murine marrow into minimally myeloablated (100 cGy) murine hosts.

Minimal myeloablative approaches are now being widely applied in the treatment of different hematological malignancies. One hundred cGy whole-body irradiation is a stem-cell-toxic, relatively non-myelotoxic treatment that allows for relatively high levels of donor chimerism. 5-Fluorouracil (5-FU) treatment leads to a relative concentration of high proliferative potential-colony-forming cell (HPP-CFC) and is an approach that has been used to induce in vivo progenitor/stem cell cycling to facilitate retroviral integration in gene therapy approaches. We have now evaluated the capacity of marrow harvested 1, 2, 6, or 12 days after 5-FU treatment (150 mg/kg) to engraft in 100 cGy-treated female BALB/c mice. Engraftment was assessed at 3, 10, and 24 weeks. A rapid induction of an engraftment defect occurred 1 day post 5-FU and persisted through day 6 with a recovery by day 12. To evaluate cell cycle status of normal and 5-FU-treated marrow cells, male donors received hydroxyurea (900 mg/kg i.v.) or phosphate-buffered saline (PBS), 2 h prior to marrow harvest and transplantation into submyeloablated female recipients. Engraftment levels were similar for hydroxyurea-treated mice and controls. Thus, these studies show transiently defective engraftment of 5-FU-treated marrow into submyeloablated hosts, which may be related to the cell cycle status of the stem cells.

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PubMedDate not supplied

Differentiation hotspots: the deterioration of hierarchy and stochasm.

The conception of the present-day model of hematopoiesis was begun by the work of Professor Ernst Neumann in the 19th century when he established that immature blood cells in the bone marrow migrate out into the blood vessels. Here was the birth of the hierarchical model of hematopoiesis. Jumping 135 years into the present day, recent data suggests that the stem cell regulation is not based on the classic hierarchical model, but instead more on a functional continuum. Presumptively, chromatin remodeling with cycle transit underlies changes in gene expression. This implies that the differentiative potential of primitive stem cells should also shift with cycle transit. This model proposes a less rigid system, at least in the early stem cell and progenitor compartments in which the functional characteristics of stem cells change as they go through cycle transit. We have shown that hematopoietic stem cells reversibly shift their engraftment phenotype with cytokine induced cell cycle transit. Other shifts include adhesion protein expression, cytokine receptor expression, gene expression, and progenitor phenotype. We have also found differentiation "hotspots", culture times (reflective of cell cycle state) at which stem cell differentiation was directed toward a specific lineage. This data inaugurates the end of a pure stochastic model. This work complements existing scientific work without discounting it and adds an additional dimension of complexity (or simplicity) to the process of hematopoiesis.

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PubMedDate not supplied

Homing and conversion of murine hematopoietic stem cells to lung.

The hematopoietic stem cell population, lineage negative-Sca positive (HSC), displays a homing defect into bone marrow (BM) after 48-h exposure to interleukin (IL)-3, IL-6, IL-11, and steel factor [J. Hematother. Stem Cell Res. 11 (2002) 913]. Cytokine treatment of murine marrow leads to reversible alterations in adhesion protein expression, which may explain the changes in homing. We evaluated 3 h homing to nonhematopoietic organs of marrow cells exposed to cytokines for 0, 18, 24, 40 and 48 h. HSC cells from C57BL/6J mice were cultured and labeled with the cytoplasmic fluorescent dye CFSE. We found homed events from uncultured cells in spleen, liver and lung, but no events were seen in duodenum or anterior tibialis muscle. Culture in cytokines led to decreased homing to marrow at 24 and 48 h with parallel changes in spleen homing. There was little variability of homing to liver, however the number, of homed events in lung was markedly increased when 24-h cultured cells were assessed. This was approximately a 10-fold increase compared to the 0 h time point (flow cytometry). Homing was determined by evaluation of frozen section (8 microm) by fluorescent microscopy for spleen, liver, duodenum, anterior tibialis and lung. Data were confirmed by flow cytometry from each organ including marrow. These data indicate the presence of a lung homing "hotspot" at 24 h of cytokine culture; this is a time when the stem progenitors cells are in mid S-phase. Altogether these data suggest that homing of marrow cell to nonmarrow organs may fluctuate with cell cycle transit and that there is a lung homing hotspot in mid-S.

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