B-cell surface phenotypes of proliferating myeloma cells: target antigens for immunotherapy

Dual-parameter flow cytometric analysis of B-cell antigens and DNA content was used to determine the phenotypes of proliferating tumor cells (S-phase cells) from 30 patients with multiple myeloma. B4 (CD19), J5 (CALLA, CD10), B1 (CD20), and monotypic surface immunoglobulin (Slg) were expressed heterogeneously in 24 patients. J5 and monotypic Slg were found most frequently but were always expressed on a significantly lower percentage of cells than the antigens typically associated with plasma cells, cytoplasmic immunoglobulin (Clg) and T10 (CD38). S-phase cells were found in each antigen(+) subset. B antigen(+) cycling cells were demonstrated in 16 patients whose marrow or blood cells expressed B antigens exclusively in the hyperdiploid fraction and therefore were certainly part of the myeloma clone. Similar to the low level of proliferative activity of the T10(+), Clg(+), and PCA1(+) subsets, the percentages of cycling cells of the preplasma cell B-antigen-bearing myeloma subsets ranged from less than 1% to 12%. The tumor cells of four patients were also studied with dual-color surface antigen analysis and demonstrated independent expression of B antigens, with only rare coexpression of T10 and monotypic Slg, J5, or B4. These findings are consistent with the presence of distinct myeloma subsets bearing differing B phenotypes in the same tumor and provide evidence that the proliferation in myeloma is occurring at various developmental stages in the malignant B lineage. These antigens may be important targets for immunologic therapy aimed at eliminating the entire proliferating compartment of this B-cell tumor.     

Differential effects of interleukin-3, interleukin-7, interleukin 15, and granulocyte-macrophage colony-stimulating factor in the generation of natural killer and B cells from primitive human fetal liver progenitors

The regulatory roles of a number of early-acting growth factors on the generation of natural killer (NK) cells and B cells from primitive progenitors were studied. Experiments focused on the contributions of granulocyte-macrophage colony-stimulates factor (GM-CSF) and interleukin-3 (IL-3) to the regulation of the early events of lymphopoiesis.Two progenitor populations isolated from human fetal liver were studied, CD38(-)CD34(++)lineage(-) (Lin(-)) cells (candidate hematopoietic stem cells [HSCs]) and the more mature CD38(+)CD34(++)Lin(-) cells. The effects of different cytokines on the generation of CD56(+)CD3(-) NK cells and CD19(+) B cells were studied in serum-deprived cultures in the absence of stroma.NK cells generated in vitro were able to kill NK-sensitive target cells, expressed NK-associated marker CD161 (NKR-P1A), but exhibited little or no expression of CD2, CD8, CD16, CD94/NKG2A, or killer cell inhibitory receptors (KIRs). Among the cytokine combinations tested, kit ligand (KL) and IL-15 provided the best conditions for generating CD56(+) NK cells from CD38(+)CD34(++)Lin(-) cells. However, either flk-2/flt3 ligand (FL), GM-CSF, IL-3, or IL-7 could partially substitute KL. All of these cytokines also supported the growth of NK-cell progenitors from candidate HSC, with the combination of IL-15, KL, GM-CSF, and FL generating the greatest number of CD56(+) cells. B cells were generated from both progenitor populations in response to the combined effects of KL, FL, and IL-7. Both B and NK cells were generated with the further addition of IL-15 to these cultures. The in vitro generated B cells were CD10(+), CD19(+), HLA-DR(+), HLA-DQ(+), and some were CD20(+), but no cytoplasmic or surface immunoglobulin M expression was observed. In contrast with NK lymphopoiesis, GM-CSF, IL-3, and IL-15 had no effect on the generation of B cells from CD38(-)CD34(++)Lin(-) cells, and GM-CSF inhibited B-cell generation from CD38(+)CD34(++)Lin(-) progenitors. These findings indicate a differential regulation of NK and B lymphopoiesis beginning in the early stages of hematopoiesis as exemplified by the distinctive roles of IL-7, IL-15, GM-CSF, and IL-3.     

Blood levels of immune cells predict survival in myeloma patients: results of an Eastern Cooperative Oncology Group phase 3 trial for newly diagnosed multiple myeloma patients.

Previously, it was reported that patients with multiple myeloma (MM) who have higher baseline levels of blood CD4(+) or CD19(+) cells have longer survival. This article extends the analysis of immune cell levels and survival in a large cohort (N = 504) of patients with MM entered on Eastern Cooperative Oncology Group (ECOG) phase 3 trial (9486). Newly diagnosed patients with MM received 2 cycles of vincristine, bischloroethylnitrosourea, melphalan, cytoxan, prednisone (VBMCP) and were treated on one of 3 randomized arms: VBMCP with either interferon or high-dose cyclophosphamide, or VBMCP alone. Blood immune cell levels were studied at trial entry (baseline), after 2 cycles of chemotherapy, after 2 years of therapy, and at relapse. Baseline CD3(+), CD4(+), CD8(+), CD19(+), and CD4(+) subset cell levels were all positively associated with survival (P =.0087 to P <.0001). A multivariate analysis incorporating CD4(+) and CD19(+) cell levels defined 3 separate groups of patients with MM to survival outcome. Higher CD19(+) blood levels were positively associated with MM-patient survival at entry to the study, at year 2, and at relapse (P <.0001 at all 3 timepoints). Patients with MM had evidence of immune cell reconstitution after 2 years of therapy, but the rate and extent of recovery was greater for CD8(+), which was greater than CD4(+), which was greater than CD19(+). This latter data affirms the positive relationship between the quantitative status of the blood immune system in MM and survival. In addition, the importance of the CD19(+) blood cells to survival is evident throughout the course of MM. Therapeutic efforts to maintain an intact immune system may be crucial in maximizing chemotherapeutic and/or immunotherapy efforts in this disease.     

Down-regulation of CD98 in melphalan-resistant myeloma cells with reduced drug uptake

Although melphalan has been used as a therapeutic reagent for multiple myeloma, many patients become refractory. To elucidate the mechanism of resistance to melphalan, we generated a melphalan-resistant myeloma cell line, KHM-11(EMS), by treating a parental line, KHM-11, with a mutagen, ethylmethanesulfonate. KHM-11(EMS) is 55 times more resistant to melphalan. gamma-Glutamylcysteine synthetase, P-glycoprotein, multidrug-resistance-associated protein, lung-resistance-related protein and the Bcl-2 family of proteins were not responsible for the drug resistance in KHM-11(EMS). Intracellular incorporation of melphalan to myeloma cells was determined by using [(14)C]-labeled melphalan. Accumulation of melphalan in KHM-11(EMS) was 43% of KHM-11, while the efflux rates were comparable in both cell lines. The uptake of melphalan was inhibited by the addition of L-phenylalanine, indicating that melphalan is incorporated through the L-phenylalanine transporter as reported previously. Expression of CD98, which was recently cloned as an L-phenylalanine transporter, was 6-fold decreased in KHM-11(EMS), suggesting that CD98 may be correlated with the incorporation of melphalan. CD98 expression and incorporation of melphalan were analyzed in fresh purified myeloma cells from 5 patients. All myeloma cells from 4 cases expressed CD98 at a high level and incorporated melphalan. However, tumor cells from 1 case expressed CD98 at low levels and did not incorporate melphalan. Taken together, reduced melphalan uptake could be responsible for the drug resistance in KHM-11(EMS), and down-regulation of CD98 may be related to this phenomenon. Further investigation of the correlation between impaired drug uptake and down-regulation of CD98 in myeloma cells should be important to understand the mechanism of resistance to melphalan.     

Down-regulation of DNA repair in human CD34(+) progenitor cells corresponds to increased drug sensitivity and apoptotic response

Although DNA repair processes have been shown to considerably modulate the cytotoxic effects of alkylating agents, little information is available on the role of these mechanisms in chemotherapy-induced myelosuppression. Therefore, we have analyzed in detail the DNA repair capacity of primary human hematopoietic cells from cord blood (CB) or bone marrow (BM) by 2 functional assays, the immunocytologic assay (ICA) and single-cell gel electrophoresis (comet assay). Besides substantial interindividual differences, we consistently observed significantly lower repair capacity of CD34(+) cells in comparison to CD34(-), CD19(+), or CD33(+) cells of the same donor. After exposure to the alkylating agent ethylnitrosourea (EtNU), the comet assay displayed on average twice as many DNA single-strand breaks (SSBs) in CD34(+) cells and a tripled half-life of these lesions in comparison to corresponding CD34(-) cells. Similarly, reduced SSB repair activity in CD34(+) cells was detected following melphalan or cisplatin application. When specific antibodies were used to monitor DNA reaction products of these drugs, adduct levels were significantly higher and lesions persisted longer in the CD34(+) fraction. To assess the contribution of individual pathways to overall DNA repair, modulators blocking defined steps in repair processes were coapplied with alkylating drugs. Similar "modulation pattern" in corresponding CD34(+) and CD34(-) cell fractions indicated a generalized reduction in DNA repair capacity of CD34(+) cells, rather than deficiencies in a specific pathway. Because CD34(+) cells also displayed higher frequencies of apoptosis in response to melphalan or cisplatin, these findings may help to explain the myelosuppression after exposure to alkylating agents.     

Atypical marginal zone hyperplasia of mucosa-associated lymphoid tissue: a reactive condition of childhood showing immunoglobulin lambda light-chain restriction

Mucosa-associated lymphoid tissue (MALT) lymphomas usually arise at sites of acquired MALT and are uncommon in native MALT (eg, Peyer patches and tonsil). Malignancy in these low-grade lymphomas is often inferred by immunoglobulin light-chain restriction and expression of CD43; molecular genetic evidence is sought only if these are in doubt. We report 6 cases (4 tonsils, 2 appendixes) of marginal zone (MZ) hyperplasia in children aged 3 to 11 years that, despite histologic and immunophenotypic features indicative of lymphoma, were polyclonal by molecular analysis. No lymphoma-directed therapy was given and patients remain alive and well (5 cases, median follow-up 35.3 months). The involved tonsil and appendix showed florid MZ hyperplasia with prominent intraepithelial B cells (IEBCs). The MZ B cells and IEBCs showed a high-proliferation fraction and a CD20(+), CD21(+), CD27(-), immunoglobulin (Ig) superfamily receptor translocation-associated 1-positive (IRTA-1(+)), CD43(+), multiple myeloma oncogene 1 (MUM-1), IgM(+)D(+) phenotype. Polymerase chain reaction (PCR), cloning, and sequencing of rearranged IgH and Iglambda genes (whole tissue sections [6 cases]; microdissected cells [2 cases]) showed that the MZ B cells and IEBCs were polyclonal and the IgH genes nonmutated. In contrast, MZ (intraepithelial) B cells of 6 control tonsils had a similar immunophenotype, except for expression of CD27 and polytypic light chains, whereas molecular studies showed that they were polyclonal with mutated Ig genes.     

CD56-expressing T cells that have features of senescence are expanded in rheumatoid arthritis

OBJECTIVE: T cells deficient in CD28 expression have been implicated in the pathogenesis of rheumatoid arthritis (RA). Given that CD28-null T cells are functionally heterogeneous, we undertook this study to screen for novel receptors on these cells. METHODS: Seventy-two patients with RA (ages 35-84 years) and 53 healthy persons (32 young controls ages 19-34 years, 21 older controls ages 39-86 years) were recruited. Phenotypes and proliferative capacity of T cells from fresh leukocytes and of long-term cultures were monitored by flow cytometry. Lung biopsy specimens from patients with RA-associated interstitial pneumonitis (IP) were examined by immunohistochemistry. Receptor functionality was assessed by crosslinking bioassays. RESULTS: Chronic stimulation of CD28(+) T cells in vitro yielded progenies that lacked CD28 but that gained CD56. Ex vivo analysis of leukocytes from patients with extraarticular RA showed a higher frequency of CD56(+),CD28-null T cells than in patients with disease confined to the joints or in healthy controls. CD56(+),CD28-null T cells had nil capacity for proliferation, consistent with cellular senescence. CD56(+) T cells had skewed T cell receptor (TCR) alpha/beta-chain usage and restricted TCR third complementarity-determining region spectra. Histologic studies showed that CD56(+) T cells were components of cellular infiltrates in RA-associated IP. CD56 crosslinking on T cells sufficiently induced cytokine production, although CD56/TCR coligation induced higher production levels. CONCLUSION: Chronic activation of T cells induces counterregulation of CD28 and CD56 expression. The loss of CD28 is accompanied by the gain of CD56 that confers TCR-independent and TCR-dependent activation pathways. We propose that accumulation of CD56(+) T cells in RA contributes to maladaptive immune responses and that CD56(+) T cells are potential targets for therapy.     

Influence of amantadine on CD81 expression on lymphocytes in chronic hepatitis C

Introduction

Interferon alpha (IFN) down regulates CD81 expression on peripheral blood mononuclear cells (PBMC) in patients with chronic hepatitis C virus (HCV) infection. Aim of our study was to investigate whether amantadine alters IFN associated down regulation of CD81 expression on PBMC in patients with chronic hepatitis C.

Methods

Nineteen patients with chronic HCV infection received peginterferon alpha-2a/ribavirin (SOC) for 48 weeks. Patients were randomised to 12 weeks amantadine therapy (n = 12) or no additional treatment (n = 7). FACS analysis of CD81 expression on CD4(+), CD8(+), CD19(+), and CD56(+) cells was performed at baseline, week (TW) 4, TW12, and TW24 of antiviral therapy.

Results

A significant decline of CD81 expression was observed on CD4(+), CD8(+), and CD56(+) cells (p = 0.011, p < 0.001, p = 0.015, respectively) but not on CD19(+) cells (p > 0.2). CD81 expression on CD4(+), CD8(+), CD19(+), and CD56(+) cells was not different between patients treated with SOC plus amantadine and patients treated with SOC alone.

Conclusion

The current study confirms that CD81 expression is down regulated by SOC on CD4(+), CD8(+) and CD56(+) cells. Amantadine treatment was not associated with CD81 expression. Interaction between amantadine and CD81 is unlikely to be involved in potential antiviral activity of amantadine in chronic HCV infection.     

CD81 expression for discrimination between sustained virologic response and relapse in patients with chronic hepatitis C

Abstract

Background and aim. The hepatitis C virus (HCV) receptor CD81 is overexpressed on peripheral blood mononuclear cells (PBMC) in patients chronically infected with HCV compared with healthy controls, and expression declines during antiviral therapy. The aim of this study was to prospectively investigate CD81 expression on PBMC for early discrimination between sustained virologic response (SVR) and relapse (REL) to pegylated interferon alfa-2b and ribavirin treatment. Methods. Sixty-one patients with chronic HCV infection (genotype, GT, 1 and low baseline viremia <600,000 IU/ml, n = 30; GT 2 or 3, n = 31) were investigated. CD81 expression on CD4(+), CD8(+), CD19(+), and CD56(+) cells was measured at baseline, therapy week (TW) 4 and 12 during antiviral therapy by fluorescence-activated cell sorting (FACS) analysis. Results. Baseline levels of CD81 on CD4(+), CD8(+), and CD56(+) cells were similar between patients who achieved a SVR (n = 42) and those who relapsed (n = 19). On CD19(+) cells, baseline CD81 expression was higher in patients with SVR than in patients with virologic relapse (REL) (p < 0.006). A cutoff value of 720 relative fluorescence units (RFU) discriminated correctly between SVR and REL with a sensitivity and specificity of 73.7% and 66.7%, respectively. SVR patients showed a significant decline of CD81 expression on CD4(+), CD8(+), CD19(+), and CD56(+) cells (p < 0.01 for all) while in REL patients a significant decline of CD81 expression was observed on CD8(+) and CD56(+) cells, only (p = 0.050 and p = 0.038, respectively). Conclusions. The current study confirms significant down-regulation of CD81 expression on different lymphocyte subpopulations during pegylated interferon alfa-based antiviral therapy in patients with chronic hepatitis C. Baseline CD81 expression on CD19(+) cells was found to discriminate between SVR and REL.     

Bone marrow subpopulations contain distinct types of endothelial progenitor cells and angiogenic cytokine-producing cells

Therapeutic angiogenesis can be induced by the implantation of bone marrow cells (BMCs). However, the mechanism of BMC-mediated neovascularization remains to be clarified. We investigated the differential activities of bone marrow subpopulations in angiogenesis and cytokine production. BMCs were separated into positive and negative fractions by surface expression of Mac-1, Gr-1, CD19, and c-kit, respectively. After 7 days of culture in the presence of vascular endothelial growth factor (VEGF), the cells produced adherent cells which incorporate acetylated low-density lipoprotein (acLDL). Mac-1(+) and Mac-1(-) cells produced almost equal numbers of acLDL(+) cells, but only Mac-1(-) cells expressed endothelial markers, including Flk-1, vWF, and CD31. Similarly, the expression of endothelial markers was detected in Gr-1(-), CD19(-), and c-kit(+) BMC fractions at 7-day cultures, but not in Gr-1(+), CD19(+), or c-kit(-) cells. In contrast, freshly isolated Mac-1(+) and Gr-1(+) BMCs expressed higher levels of mRNAs for angiogenic cytokines (including VEGF-A, FGF-2, and HGF) than Mac-1(-) and Gr-1(-) cells, respectively. Moreover, Mac-1(+)/c-kit(+) BMC subpopulation expressed higher levels of VEGF-A and SDF-1 mRNAs than other subpopulations. These data demonstrate that a relatively small proportion of VEGF-cultured adherent cells are true endothelial cells with a Flk-1(+)/vWF(+)/CD31(+) phenotype. Moreover, endothelial stem/progenitor cells (EPCs) are limited primarily to Mac-1(-), Gr-1(-), and c-kit(+) BMC populations. In contrast, angiogenic cytokine mRNAs were also produced by Mac-1(+), Gr-1(+), and c-kit(-) BMCs, suggesting the heterogeneity of effector cell types for neovasculatization therapy.     

Immune reconstitution after autologous hematopoietic stem cell transplantation in relation to underlying disease, type of high-dose therapy and infectious complications

BACKGROUND AND OBJECTIVES: Autologous peripheral stem cell transplantation (APSCT) is increasingly used for various hematologic malignancies and solid tumors. The objective of this study was to analyze the immune reconstitution after APSCT and see if there was any correlation with diagnosis, age, type of high-dose therapy, CD34(+) selection of the autograft and double vs single APSCT. DESIGN AND METHODS: Lymphocyte subset recovery was studied in 46 consecutive patients with hematologic malignancies and breast cancer, who underwent APSCT. Eleven patients with multiple myeloma received tandem autografts. Thirty-one patients were given total body irradiation (TBI) as part of the high-dose treatment. Eighteen patients received a CD34(+) selected graft. The percentage and absolute numbers of lymphocyte populations, T-cells (CD2(+), CD3(+)), B-cells (CD19(+)), NK cells (CD56(+ )CD3(-) and CD16(+)CD3(-)) and T-cell subpopulations (CD4(+), CD8(+), CD4(+)CD45RA(+), CD4(+ )CD45RO(+), CD4(+)DR(+), CD8(+ )CD45RO(+), CD8(+)DR(+)), were monitored with flow cytometry during the first year after APSCT. RESULTS: The total B-cell (CD19(+)) and T-cell (CD3(+)) counts were reconstituted to normal levels 2-4 months after APSCT. All patients had a low CD4/CD8 ratio during the observation period, related to both a low number of CD4(+) cells and elevated numbers of CD8(+) cells. The low number of CD4(+) cells was due to a persistently low level of naive CD4(+)CD45RA(+) cells. A high proportion of the CD8+ cells displayed a phenotype compatible with activated T-cells (CD8(+)DR(+)) up to 10 months after autografting. The number of NK cells (CD56(+)3(-) or CD16(+)3(-)) reached normal values within one month post-transplant. No single variable, such as diagnoses, age, TBI as part of the high-dose treatment, tandem autografting or CD34(+) selection of the graft, influenced the immune or hematopoietic reconstitution and no correlation with documented infectious complications was found. INTERPRETATION AND CONCLUSIONS: Despite heterogeneity of diseases, age, initial treatment and high-dose regimens, lymphocyte subset analysis did not reveal any differences in hematopoietic or immune reconstitution. All patients had a low CD4(+)/CD8(+) ratio during at least the first year post-transplant, caused by a persistent increase of CD8(+) lymphocytes and a constant reduction of CD4(+) lymphocytes, making the patients susceptible to infections for a prolonged period of time post-transplant.     

Peripheral blood but not tissue dendritic cells express CD52 and are depleted by treatment with alemtuzumab

CAMPATH antibodies recognize CD52, a phosphatidylinositol-linked membrane protein expressed by mature lymphocytes and monocytes. Since some antigen-presenting dendritic cells (DCs) differentiate from a monocytic progenitor, we investigated the expression of CD52 on dendritic cell subsets. Four-color staining for lineage markers (CD3, 14, 16, 19, 20, 34, and 56), HLA-DR, CD52, and CD123 or CD11c demonstrated that myeloid peripheral blood (PB) DCs, defined as lineage(-)HLA-DR(+)CD11c(+), express CD52, while expression by CD123(+) lymphoid DCs was variable. Depletion of CD52(+) cells from normal PB strongly inhibited their stimulatory activity in an allogeneic mixed lymphocyte reaction and also reduced the primary autologous response to the potent neoantigen keyhole limpet hemocyanin. CD52 is thus expressed by a myeloid subset of PBDCs that is strongly allostimulatory and capable of initiating a primary immune response to soluble antigen. Administration of alemtuzumab, a humanized monoclonal antibody against CD52, to patients with lymphoproliferative disorders or as conditioning for hematopoietic stem cell transplantation resulted in a marked reduction in circulating lineage(-)HLA-DR(+) DCs (mean 31-fold reduction, P =.043). Analysis of monocyte-derived DCs in vitro revealed a reduction in CD52 expression during culture in granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin-4, with complete loss following activation-induced maturation with lipopolysaccharide. In contrast to the findings in PB, epidermal and small-intestine DCs did not express CD52, suggesting either that transit from blood to epidermis and gut is associated with loss of CD52 or that DCs in these tissues originate from another population of cells.     

Early proliferation of CCR5(+) CD38(+++) antigen-specific CD4(+) Th1 effector cells during primary HIV-1 infection

We investigated whether HIV-1 antigen-specific CD4(+) T cells expressed the viral coreceptor CCR5 during primary HIV-1 infection (PHI). In the peripheral blood of subjects with very early PHI (< 22 days after onset of symptoms), there was a 10- to 20-fold increase in the proportion of highly activated (CD38(+++)) and proliferating (Ki-67(+)) CD4(+) T cells that expressed CCR5(+), and were mostly T-cell intracellular antigen-1 (TIA-1)(+) perforin(+) granzyme B(+). Inthe same patient samples, CD4(+) T cells producing interferon (IFN)-gamma in response to HIV group-specific antigen (Gag) peptides were readily detected (median, 0.58%) by intracellular cytokine assay-these cells were again predominantly CD38(+++), Ki-67(+), and TIA-(++), as well as Bcl-2(low). On average, 20% of the Gag-specific CD4(+) T cells also expressed interleukin-2 (IL-2) and were CD127 (IL-7R)(+). Taken together, these results suggest that Gag-specific T-helper 1 (Th1) effector cells express CCR5 during the primary response and may include precursors of long-term self-renewing memory cells. However, in PHI subjects with later presentation, antigen-specific CD4(+) T cells could not be readily detected (median, 0.08%), coinciding with a 5-fold lower level of the CCR5(+)CD38(+++) CD4(+) T cells. These results suggest that the antiviral response to HIV-1 infection includes highly activated CCR5(+)CD4(+) cytotoxic effector cells, which are susceptible to both apoptosis and cytopathic infection with HIV-1, and rapidly decline.     

Differential engraftment of genetically modified CD34(+) and CD34(-) hematopoietic cell subsets in lethally irradiated baboons

OBJECTIVE: To test gibbon ape leukemia virus (GALV) pseudotype vector transduction of marrow subpopulations that contribute to hematopoietic reconstitution in vivo. MATERIALS AND METHODS: Autologous CD34(+) Lin(-), CD34(+) Lin(+), and CD34(-) Lin(-) marrow cells, transduced by coculture with PG13/LN, PG13/LNX, and PG13/LNY vector-producing cells, respectively, were transplanted in three female baboons. Two female baboons also were transplanted with fresh allogeneic CD34(-)Lin(-) marrow cells from MHC-matched male siblings and, to ensure survival, with autologous CD34(+)Lin(-) and CD34(+)Lin(+) marrow cells transduced with PG13/LN and PG13/LNX, respectively. The LN, LNX, and LNY vectors are identical except for different length sequences at the 3' end of the bacterial neomycin phosphotransferase (neo) gene. RESULTS: LN(+) and LNX(+) cells from CD34(+)Lin(-) and CD34(+)Lin(+) cells, respectively, but no LNY(+) from CD34(-)Lin(-) cells were detectable in blood and marrow of all animals after transplant. LN(+), CD34(+)Lin(-) cells contributed to reconstitution of the T, B, and myeloid lineages. LNX(+), CD34(+)Lin(+) cells contributed only to B and myeloid lineages. Male cells, CD34(-)Lin(-), were detected by polymerase chain reaction in blood and marrow of the two allogeneic transplanted animals at estimated frequencies of 相似文献   

Differential expression of CD56 and CD44 in the evolution of extramedullary myeloma

We report on the different expression of CD56 and CD44 in plasma cells (PCs) simultaneously collected from bone marrow, extramedullary locations and peripheral blood in seven patients with multiple myeloma. Extramedullary PCs showed absence of CD56. In the bone marrow, however, subsets with varying CD56 expression were found in five out of seven patients, with one subset corresponding to that of extramedullar PCs. This differs from the de novo downregulation of CD56 in PC leukaemia, and suggests different mechanisms of spread of myeloma cells. CD44 expression was generally upregulated on extramedullary PCs. In three of the patients we investigated the clonal origin of extramedullary myeloma cells by sequencing the variable portion of the heavy chain immunoglobulin gene in phenotypically defined PCs isolated from different locations. In each patient we found malignant PCs with different homing behaviour originating from a common precursor cell.     

Expression of cytoadhesion molecules (CD56, CD54, CD18 and CD29) by myeloma plasma cells

Recently we reported the expression of the human natural killer cell associated antigen CD56 (Leu 19/NKH1) in plasma cells of a majority of multiple myeloma (MM) patients. CD56 is known to be an isoform of the human neural adhesion molecule N-CAM which is involved in homotypic adhesive interactions. By immunophenotyping using four CD56 specific monoclonal antibodies and immunoprecipitation analysis we here confirm that the Leu 19 antigen expressed by myeloma plasma cells is identical to N-CAM and corresponds to the 145 kDa isoform. Because of the possible biological role of adhesion molecules on myeloma cells, we compared the expression of N-CAM with the intercellular adhesion molecule 1 (ICAM-1) and the beta 1 and beta 2 integrins. By immunogold-silver staining of cytospin preparations of mononuclear cell suspensions, bone marrow plasma cells of 17 MM patients were analysed. Plasma cells expressed N-CAM (CD56) in 14 patients. ICAM-1 (CD54) in 16 patients, and beta 2 integrins (CD18) in eight patients. beta 1 integrins (CD29) were expressed in all patients. The expression of beta 2 integrins was always very weak while N-CAM, ICAM-1 and the beta 1 integrins showed a moderate to strong positivity. The plasma cells of five haematological normal individuals lacked significant N-CAM expression but were positive for ICAM-1 and both integrin subgroups. One plasma cell leukaemia patient and two out of four end-stage MM patients showed no expression of N-CAM or beta 2 integrins on their circulating plasma cells. Among 11 previously established myeloma cell lines, surface expression of ICAM-1 and the integrins was detected in most cases, while N-CAM was present in only four lines. Most cell lines showed coexpression of the fibronectin receptors (VLA-4 and VLA-5) and the laminin receptor (VLA-6). The collagen receptor (VLA-2) was not expressed. The N-CAM negative cell lines included four cell lines that were derived from plasma cell leukaemia patients. These results indicate that the expression of adhesion molecules is an intrinsic part of the biology of multiple myeloma.     

Expression of CD86 in acute myelogenous leukemia is a marker of dendritic/monocytic lineage

OBJECTIVE: The aim of this study was to determine whether expression of the CD86 costimulatory molecule in acute myeloid leukemia (AML) can identify blast cells committed to the monocytic/dendritic lineage. MATERIAL AND METHODS: One hundred ten consecutive AML patients observed at diagnosis were studied by flow cytometry. In selected experiments, in vitro cultures with CD34(+)CD86(+) or CD34(-)CD86(+) blasts were performed in the presence of granulocyte-macrophage colony-stimulating actor (GM-CSF) with or without tumor necrosis factor-alpha (TNF-alpha) or GM-CSF + interleukin-4 (IL-4), respectively, to induce a dendritic differentiation, documented by morphologic and immunophenotypic assays. T-cell alloreactivity to CD86(+) AML cells and leukemic dendritic cells (AML-DC) was tested in mixed leukocyte cultures and anti-leukemic cytotoxic assays. RESULTS: CD86 was expressed in 54% AML, whereas CD80 and CD1a were only occasionally positive. CD86(+) AML samples included M5 and M4, but also 47% M0-M1 FAB types, and were more frequently CD14(+) (p < 0.00001) and CD34(-) (p = 0.00005) than CD86(-)AML. Six different patterns of CD86(+) AML were identified, according to CD34 or CD14 total or partial coexpression. Four samples enriched in CD34(+)CD86(+) AML cells differentiated into AML-DC CD86(+), CD80(+), CD40(+), CD11c(+), HLA-DR(++), CD14(+/-) that also were CD1a(+) or CD83(+), after 6 days of in vitro culture with GM-CSF +/- TNF-alpha. CD34(-)CD86(+) AML cells differentiated into AML-DC after 3 to 5 days (n = 5 experiments), and trisomy 8 was found in two AML and AML-DC samples by fluorescence in situ hybridization analysis. Finally, AML-DC induced more potent allo-T-cell proliferation, cytokine release, and anti-leukemic cytotoxicity than CD86(+) blasts. CONCLUSIONS: In AML, CD86 is a marker of monocytic/dendritic lineage. Because CD86(+) blasts may differentiate into DC rapidly, CD86(+)AML patients could be optimal candidates for immunotherapy studies, both in autologous and allogeneic settings.     

Chronic gingivitis in a new BTK mutation

A 5-yr-old Caucasian boy with a new mutation in Bruton's tyrosine kinase (BTK) is described. Full sequencing of the BTK gene revealed a point mutation in exon 17 resulting in an amino acid change from tryptophan to serine at location 581 of the tyrosine kinase domain. Clinically the child presented with chronic gingivitis and had no prior history of bacterial infections. Whereas serum immunoglobulin M (IgM) levels were undetectable, IgG levels were in the low normal range. The gingivitis completely resolved after intravenous immunoglobulin therapy. Lymphocyte phenotyping revealed 0.05% B cells in his peripheral blood, which were IgG(-), IgM(+), IgD(+), CD38(+), CD20(+), CD27(-). However, 40% of the B cells also expressed CD5. This subpopulation of B cells has not previously been described in X-linked agammaglobulinaemia (XLA) patients. We suggest that the occurrence of CD5(+) B cells could correlate with a late onset and mild clinical presentations of XLA.