Isolated Plasma Cells Research Articles

Elevated Expression of CKS1B at 1q21 Is Highly Correlated with Short Survival in Myeloma.

The variability in survival among patients with myeloma can range from months to >10 years. Patients at highest risk are best identified by the presence or absence of an abnormal karyotype found by conventional cytogenetics. However, this test only accounts for ~15% of the variability in outcome. Thus, many patients who present with no cytogenetic abnormalities experience rapid relapse and early death. To better define high-risk disease and also potentially identify specific genetic mechanisms that give rise to this poor survival, we analyzed the gene expression patterns in freshly isolated plasma cells from 40 newly diagnosed myeloma patients who were then treated with high-dose therapy and tandem stem cell transplants. Patients were separated into two groups of 20. Those in the “short-survival” group all died within 900 days of therapy initiation due to disease progression. Patients in the “long-survival” group had all survived >1453 days since therapy initiation. RNA from plasma cells was labeled and hybridized to the U133Plus2.0 microarray containing ~33,000 genes. The expression value was transformed by the log base 2 and each sample was normalized to give a mean of 0 and a variance of 1. Chi-square analyses and t-tests were performed to identify genes whose expression patterns were unique to each group. Kaplan-Meier analysis of overall survival using expression level quartiles was used to demonstrate links to outcome. A total of 1770 probe sets were significantly differentially expressed between the two groups (P <.05). A total of 1025 (58%) of the probe sets were up-regulated in the short-survival group. The chromosomal map positions of all 1770 probe sets were determined; 19% mapped to chromosome 1. Of the 1770 probe sets, 84 demonstrating a >2-fold difference in expression were further analyzed with Kaplan-Meier survival analyses. In this test, 18 probe sets representing 17 genes were highly significant (P <.0001). Of the 17 genes identified, 10 map to chromosome 1; all 4 genes from the p arm were down-regulated while all 6 genes from the q arm were up-regulated in the short-survival group. We have previously demonstrated that jumping 1q and amplification of genes from 1q21 represent common genetic lesions in myeloma. We then examined by FISH, BCL2 and IL-6R showed highly variable over-expression in patient subsets, unrelated to outcome. CKS1B, an evolutionarily conserved protein that interacts genetically and physically with cyclin-dependent kinases and promotes mitosis, is located very near the 1q21 amplification and is over-expressed in myelomas with a short survival. Using FISH analysis with probes specific for these genes, we will determine if over-expression is due to gene amplification. Given the important role of CKS1B in controlling mitosis and the emerging role of D-type cyclins in myelomagenesis, this gene represents a strong candidate for a gene whose over-expression, possibly as a result of gene amplification, may impart a highly aggressive phenotype on malignant plasma cells.

Plasma cell survival is mediated by synergistic effects of cytokines and adhesion-dependent signals.

Recent results suggest that plasma cell longevity is not an intrinsic capacity, but depends on yet unknown factors produced in their environment. In this study, we show that the cytokines IL-5, IL-6, TNF-alpha, and stromal cell-derived factor-1alpha as well as signaling via CD44 support the survival of isolated bone marrow plasma cells. The cytokines IL-7 and stem cell factor, crucially important for early B cell development, do not mediate plasma cell survival, indicating that plasma cells and early B cells have different survival requirements. As shown in IL-6-deficient mice, IL-6 is required for a normal induction, but not for the maintenance of plasma cell responses in vivo, indicating that the effects of individual survival factors are redundant. Optimal survival of isolated plasma cells requires stimulation by a combination of factors acting synergistically. These results strongly support the concept that plasma cell survival depends on niches in which a combination of specific signals, including IL-5, IL-6, stromal cell-derived factor-1alpha, TNF-alpha, and ligands for CD44, provides an environment required to mediate plasma cell longevity.

Proteasome inhibitors induce growth inhibition and apoptosis in myeloma cell lines and in human bone marrow myeloma cells irrespective of chromosome 13 deletion.

In this study, we investigated the effects of cell-permeable proteasome inhibitors MG-132, MG-262, PSI, and lactacystin on multiple myeloma cell lines OPM-2, U266, RPMI 8226-S, freshly isolated plasma cells with or without deletion of chromosome 13 from patients with multiple myeloma and plasma cell leukemia, and CD34+ human hematopoietic stem cells. The effects of proteasome inhibitors on cell cycle progression, cell growth, and apoptosis were determined. MTT-assay was used to examine the cytotoxicity, and annexin-V staining to quantify apoptosis. Cell cycle analyses were performed using 7-ADD and Ki-67 staining by flow cytometry. PSI was the most potent proteasome inhibitor among those tested with a half maximal cytotoxicity (IC(50)) of 5.7 nM, followed by MG-262, MG-132, and lactacystin. Growth inhibition occurred irrespective of chromosome 13 status. Cell cycle arrest occurred in a dose- and time-dependent manner. Low, subapoptotic dosages led to a partial loss of Ki-67 antigen, whereas apoptotic dosages led to reduced Ki-67 levels. Apoptosis was partially dependent on activation of caspase-3, since Ac-DEVD-cho, a caspase-3 inhibitor, could reduce apoptosis significantly. The cytotoxicity of the four proteasome inhibitors tested was significantly lower in human hematopoietic stem cells than in myeloma cells. Our results show that proteasome inhibitors induce time- and dose-dependent cell cycle alterations, growth inhibition, and apoptosis in human myeloma cells irrespective of chromosome 13 deletion.

Chronic endometritis: The role of immunohistochemistry in the detection of plasma cells

The diagnosis of chronic endometritis depends upon the detection of plasma cells within the inflammatory infiltrate in the endometrium. To determine whether an immunohistochemical stain for plasma cells would enhance the detection of them and the diagnosis of chronic endometritis, we investigated 65 cases, including normal, proliferative, and secretory endometria, late menstrual endometria, endometrial polyps, and cases suspected of being, or diagnostic for, chronic endometritis. Twenty cases were positive by immunoperoxidase staining, 14 of which were positive by morphologic evaluation. Scattered isolated plasma cells which had been missed by histologic examination were detected by immunoperoxidase in three cases of early proliferative endometrium, and one case each of cystic glandular hyperplasia, 16-day endometrium, and late menstrual endometrium. Hence, the immunoperoxidase technique was more sensitive for detecting isolated plasma cells which were missed by standard screening techniques. In addition, the immunoperoxidase stain was useful for defining the spectrum of plasma cell morphologic characteristics within endometrium and, in retrospect, confirmed the differences between plasma cell and endometrial stromal cell morphologic features on hematoxylin and eosin sections.

Concanavalin A receptor sites on lymph node cells in vivo and in vitro.

The distribution and density of receptors for concanavalin A (Con A) on the surfaces of cells of intact and isolated popliteal and axillary lymph nodes were investigated in the rabbit. Intact lymph nodes were perfused via the subcapsular (marginal) sinus with either Con A peroxidase or Con A ferritin, fixed with glutaraldehyde, and processed for electron microscopy. Both Con A peroxidase and Con A ferritin were distributed on the plasmalemma of lymphocytes, macrophages, neutrophils, plasma cells, reticular endothelial cells, and the vascular endothelium. Counts of Con A-conjugated ferritin particles indicated that the density of Con A receptors was generally similar for lymphocytes, macrophages, and neutrophils but lower on plasma cells. When lymph node cells were isolated by mechanical methods and exposed to Con A ferritin, the label was homogenously distributed on the cell surfaces of most cells. However, Con A binding was significantly higher on the surface of isolated cells than in the intact node. It is suggested that the increase in density of Con A binding sites on isolated cells may possibly be due to an unmasking of cell surface moieties in which additional Con A receptor sites become available as a result of the isolation procedure. The density of Con A ferritin binding sites was also significantly lower on the surface of isolated plasma cells than the lymphocyte and macrophage, suggesting that the density distribution of cell surface saccharides is different for various lymphoid cells.

Immunohistochemical localization of amylase, lysozyme and immunoglobulins in the human parotid gland

Fluorochrome-labelled antibodies to human amylase, lysozyme and immunoglobulins reveal a different cellular source for each of these proteins in the human parotid gland. Amylase is produced in acinar and adjoining intercalated duct cells. Lysozyme is secreted by special cells which extend from the basement membrane toward the duct lumen and whose nuclei lie peripherally to the nuclei of the striated cells. Among the immunoglobulins, IgG has not been detected, IgM is found in few isolated plasma cells, IgA is demonstrable in clusters of plasma cells along intralobular ducts and in scattered areas inside striated duct cells. The anatomic orientation has been facilitated by fluorescent markers.