Leukocyte Lineages Research Articles

The expression of human resistin in different leucocyte lineages is modulated by LPS and TNFα

Objective Human resistin has been linked to several inflammatory diseases such as atherosclerosis. This study aimed to clarify the expression of resistin in different inflammatory cells and its effect on endothelial cells. Results In this study, RNA and protein expression of resistin were detected in human primary neutrophils, monocytes, and T cells as well as in human Jurkat T cells, RPMI-8226 B cells, monocytic U937, and myeloblastic HL-60 cell lines. The highest resistin protein and mRNA level were detected in neutrophils, primary monocytes, and monocytic U937 cells. The RNA expression of resistin was upregulated both in neutrophils and in U937 cells after exposure to LPS. Also TNFα induced resistin RNA expression in neutrophils, U937, T-lymphocytic Jurkat cells, and B-lymphocytic RPMI-8226 cells. The RNA and protein expression of resistin decreased as the monocytic U937 cells differentiated into macrophage-like cells. In endothelial EA.hy 926 cells, resistin increased the expression of MCP-1 and PECAM-1 and adhesion of monocytes to endothelial cells. Conclusions The wide-ranging expression of resistin in white blood cells and the upregulation of its expression by inflammatory reagents LPS and TNFα support the fact that increased resistin could be involved in several inflammatory diseases.

Involvement of bone marrow‐derived stromal cells in gastrointestinal cancer development and metastasis

The involvement of bone marrow (BM) in tumor-stroma reactions or tumor development has not been examined in a cancer allograft, which has otherwise been appropriate for assessing therapeutic modalities. We investigated the fate of BM-derived cells in colon cancer allografts and liver metastases in mice. C57BL/6 mice were irradiated and rescued by BM transplantation from green fluorescent protein (GFP)-transgenic mice. MC38 colon cancer cells were stably transfected with the pDsRed gene in order to identify tumor cells by fluorescence. These were inoculated into the mice to generate subcutaneous allografted tumors or liver metastases. The tumors were observed under confocal microscopy and fluorescent immunohistochemistry to determine the fate of tumor versus BM-derived cells. GFP-positive (GFP(+)) cells were consistently identified as vimentin(+), alpha-smooth muscle actin (alphaSMA)(+), spindle-shaped stromal cells in both the subcutaneous tumors and the liver metastases. GFP(+) cells of leukocyte lineage also infiltrated the tumors. Neither GFP(+) CD31(+) endothelial cells nor GFP(+) DsRed(+) cells were detected in the tumor. BM-derived cells frequently and consistently infiltrated the tumor allografts and metastases as interstitial cells and leukocytes. Cells derived from the fusion of BM cells and tumor cells were not observed. This model may be appropriate for the clarification of the effects of anticancer therapies and the study of BM-derived cells in tumor-host interactions.

Matrix metalloproteinase‐9 contributes to intestinal tumourigenesis in the adenomatous polyposis coli multiple intestinal neoplasia mouse

Matrix metalloproteinases (MMPs) are a family of 23 extracellular proteases that are best known for their collective ability to degrade all components of the extracellular matrix. We previously demonstrated that genetic ablation of MMP-7 reduced tumour multiplicity in multiple intestinal neoplasia (Min) mice possessing a genetic alteration in the adenomatous polyposis coli gene (APC). These mice, commonly referred to as APC-Min mice, are a frequently used model of early intestinal tumourigenesis. To examine further the role of MMPs in intestinal tumour development, we generated APC-Min mice genetically deficient in MMP-2, -9, -12 or -19. Genetic ablation of MMP-2, -12 or -19 did not affect multiplicity or size of intestinal tumours when crossed into the APC-Min system. However, MMP-9 deficient animals developed 40% fewer tumours than littermate controls, although tumour size distribution remained unaffected. Intestinal adenomas from MMP-9 deficient mice demonstrated a 50% decrease in proliferating cells compared with control tissues, with no difference in apoptosis. To determine the cellular origin of MMP-9 in these tumours, immunofluorescent co-staining with markers for different leucocyte lineages was used to demonstrate that intratumoural MMP-9 is largely a product of neutrophils. These studies extend the potential targets for chemoprevention of intestinal adenomas to MMP-9 in addition to MMP-7 and exclude MMP-2,-12,-19 as attractive targets for intervention.

The Role of Rac2 in Regulating Neutrophil Production in the Bone Marrow and Circulating Neutrophil Counts

Circulating neutrophils are persistently higher in mice deficient in the small GTPase Rac2 than in wild-type (WT) mice. Therefore, we examined the mechanisms through which the small GTPase Rac2 regulates neutrophil production and release. Lethally irradiated WT mice reconstituted with a 50:50 mixture of WT and Rac2(-/-) fetal liver cells were protected from neutrophilia, suggesting that neutrophilia is primarily because of extrinsic defects that can be corrected by WT leukocytes. However, the differential counts and numbers of leukocyte subtypes differed between Rac2(-/-) and WT cells, suggesting that Rac2 modulates leukocyte lineage distribution. Kinetic studies suggest Rac2 modulates the release of neutrophils into the circulation and does not prolong their circulating half life. The percentage of bone marrow cells that expressed the neutrophil marker Gr-1 in lethally irradiated WT or Rac2(-/-) recipients of Rac2(-/-) stem cells was greater than in recipients of WT stem cells; however, circulating neutrophil counts were higher only in Rac2(-/-) recipients of Rac2(-/-) stem cells. Rac2 mRNA was expressed in the bone marrow of WT recipients of Rac2(-/-) stem cells and in human mesenchymal stem cells. The data presented here suggest that Rac2 in hematopoietic cells regulates leukocyte lineage distribution and Rac2 in nonhematopoietic cells might contribute to regulating circulating neutrophil counts.

Biophysical Characterization of O-Glycosylated CD99 Recognition by Paired Ig-like Type 2 Receptors

Paired Ig-like type 2 receptors (PILRs) are one of the paired receptor families, which consist of two functionally opposite members, inhibitory (PILRalpha) and activating (PILRbeta) receptors. PILRs are widely expressed in immune cells and recognize the sialylated O-glycosylated ligand CD99, which is expressed on activated T cells, to regulate immune responses. To date, their biophysical properties have not yet been examined. Here we report the affinity, kinetic, and thermodynamic analyses of PILR-CD99 interactions using surface plasmon resonance (SPR) together with site-directed mutagenesis. The SPR analysis clearly demonstrated that inhibitory PILRalpha can bind to CD99 with low affinity (K(d) approximately 2.2 microm), but activating PILRbeta binds with approximately 40 times lower affinity (K(d) approximately 85 microm). In addition to our previous mutagenesis study (Wang, J., Shiratori, I., Saito, T., Lanier, L. L., and Arase, H. (2008) J. Immunol. 180, 1686-1693), the SPR analysis showed that PILRalpha can bind to each Ala mutant of the two CD99 O-glycosylated sites (Thr-45 and Thr-50) with similar binding affinity to wild-type CD99. This indicated that both residues act as independent and equivalent PILRalpha binding sites, consistent with the highly flexible structure of CD99. On the other hand, it is further confirmed that PILRbeta can bind the T50A mutant, but not the T45A mutant, indicating a recognition difference between PILRalpha and PILRbeta. Kinetic studies demonstrated that the PILR-CD99 interactions show fast dissociation rates, typical of cell-cell recognition receptors. Thermodynamic analyses revealed that the PILRalpha-CD99 interaction is enthalpically driven with a large entropy loss (-TDeltaS = 8.9 kcal.mol(-1)), suggesting the reduction of flexibility upon complex formation. This is in contrast to the entropically driven binding of selectins to sugar-modified ligands involved in leukocyte rolling and infiltration, which may reflect their functional differences.

Structurally Distinct Phosphatases CD45 and CD148 Both Regulate B Cell and Macrophage Immunoreceptor Signaling

The receptor-type protein tyrosine phosphatase (RPTP) CD148 is thought to have an inhibitory function in signaling and proliferation in nonhematopoietic cells. However, its role in the immune system has not been thoroughly studied. Our analysis of CD148 loss-of-function mice showed that CD148 has a positive regulatory function in B cells and macrophages, similar to the role of CD45 as a positive regulator of Src family kinases (SFKs). Analysis of CD148 and CD45 doubly deficient B cells and macrophages revealed hyperphosphorylation of the C-terminal inhibitory tyrosine of SFKs accompanied by substantial alterations in B and myeloid lineage development and defective immunoreceptor signaling. Because these findings suggest the C-terminal tyrosine of SFKs is a common substrate for both CD148 and CD45 phosphatases and imply a level of redundancy not previously appreciated, a reassessment of the function of CD45 in the B and myeloid lineages based on prior data from the CD45-deficient mouse is warranted.

Molecular mechanisms linking wound inflammation and fibrosis: knockdown of osteopontin leads to rapid repair and reduced scarring

Previous studies of tissue repair have revealed osteopontin (OPN) to be up-regulated in association with the wound inflammatory response. We hypothesize that OPN may contribute to inflammation-associated fibrosis. In a series of in vitro and in vivo studies, we analyze the effects of blocking OPN expression at the wound, and determine which inflammatory cells, and which paracrine factors from these cells, may be responsible for triggering OPN expression in wound fibroblasts. Delivery of OPN antisense oligodeoxynucleotides into mouse skin wounds by release from Pluronic gel decreases OPN protein levels at the wound and results in accelerated healing and reduced granulation tissue formation and scarring. To identify which leukocytic lineages may be responsible for OPN expression, we cultured fibroblasts in macrophage-, neutrophil-, or mast cell–conditioned media (CM), and found that macrophage- and mast cell–secreted factors, specifically platelet-derived growth factor (PDGF), induced fibroblast OPN expression. Correspondingly, Gleevec, which blocks PDGF receptor signaling, and PDGF-Rβ–neutralizing antibodies, inhibited OPN induction by macrophage-CM. These studies indicate that inflammation-triggered expression of OPN both hinders the rate of repair and contributes to wound fibrosis. Thus, OPN and PDGF are potential targets for therapeutic modulation of skin repair to improve healing rate and quality.

Use of flow cytometry to develop and characterize a set of monoclonal antibodies specific for rabbit leukocyte differentiation molecules

Flow cytometry was used to identify and characterize monoclonal antibodies (mAbs) that react with rabbit leukocyte differentiation molecules (LDM). Screening sets of mAbs, developed against LDM in other species, for reactivity with rabbit LDM yielded 11 mAbs that recognize conserved epitopes on rabbit LDM orthologues and multiple mAbs that recognize epitopes expressed on the major histocompatibility class I or class II molecules. Screening of mAbs submitted to the Animal Homologues Section of the Eighth Human Leukocyte Differentiation Workshop yielded 7 additional mAbs. Screening of mAbs generated from mice immunized with leukocytes from rabbit thymus or spleen or concanavalin A activated peripheral blood and/or spleen lymphocytes has yielded 42 mAbs that recognize species restricted epitopes expressed on one or more lineages of leukocytes. Screening of the anti-rabbit mAbs against leukocytes from other species yielded one additional mAb. The studies show that screening of existing sets of mAbs for reactivity with rabbit LDM will not be productive and that a direct approach will be needed to develop mAbs for research in rabbits. The flow cytometric approach we developed to screen for mAbs of interest offers a way for individual laboratories to identify and characterize mAbs to LDM in rabbits and other species. A web-based program we developed provides a source of information that will facilitate analysis. It contains a searchable data base on known CD molecules and a data base on mAbs, known to react with LDM in one or more species of artiodactyla, equidae, carnivora, and or lagomorpha.

Quantitative Monitoring of Lineage-Specific Chimerism after Dual Hematopoietic Stem Cell Transplantation (Umbilical Cord Blood with Co-Infusion of Third Party Donor CD34+ Cells).

Background: Allogeneic umbilical cord blood (UCB) stem cell transplantation (SCT) shows some advantages (HLA matching requirements or availability) respect to SCT using other sources of matched unrelated donor (MUD) stem cells. However, it is correlated with slower engraftment, increasing risk of infections and early mortality. It has been recently shown that co-infusion of third party donor (TPD) CD34+ cells (dual SCT) is useful to speed up engraftment.Objective: To evaluate the usefulness of lineage-specific chimerism quantification in the management of this transplant setting.Patients and methods: 8 dual SCT (Tables 1, 2) in 7 patients (1 CML-BC, 2 AML-M2, 1 AML-M4, 1 ALL-Ph+, 1 biphen. ALL, 1 NHL). Chimerism was analyzed by STR-PCR (AmpFlSTR SGM Plus, Applied Biosystems; sensitivity 1%) and quantitative real-time PCR (qrt-PCR) of null alleles and insertion/deletion polymorphisms (Light Cycler, Roche; sensitivity 0,01%). Peripheral blood (PB) and leukocyte lineages (T cells, CD3+, and myeloid cells, CD15+), isolated by positive selection using automated immunomagnetic technology (AutoMACS, Miltenyi Biotec), were analyzed weekly. Bone marrow (BM) was analyzed at days +30, +100, +180 and +365).Results: 7/8 cases showed initially a high proportion of TPD cells in PB which were progressively replaced by UCB cells. UCB complete chimerism (UCB-CC, absence of recipient or TPD cells even in qrt-PCR assays) was acquired in a median of 22.5 days (range 18–39). In one patient, fully HLA-mismatched with the TPD, no TPD cells were observed after dual SCT. 4/8 cases showed recipient cells in PB after dual SCT during a median period of 12 days (range 4–18 days). In 3/8 cases, recipient cells were found after CC had been acquired, which allowed early diagnosis of 1 graft rejection and 2 relapses. T cells (CD3+) are mainly of UCB origin early after dual SCT and reach UCB-CC a median of 7 days (range 0–21) before PB. However, myeloid cells (CD15+) derive primarily from the TPD and reach CC together with PB. TPD cellularity favoured early engraftment (before UCB-CC took place) in 4 cases. In this context, only one important infectious complication (hepatosplenic tuberculosis) was observed, which resolved with the appropriate treatment.Conclusions: Lineage-specific chimerism quantification allowed a close monitoring of the dynamics of engraftment of cells of both donors which is of key importance in this SCT setting. Moreover, lineage-specific chimerism analysis was useful to diagnose one graft rejection and two relapses (the patient with NHL showed a ganglionar relapse in CC). [Display omitted] [Display omitted]

Correlation between Flow Cytometry Immunophenotyping, Chimerism Quantification and IGH Gene Rearrangement Analysis in Disease Associated Leukocyte Lineages after Stem Cell Transplantation in an ALL Patient.

INTRODUCTION: Oligocloanality is a phenomenon shown in up to 40% of patients with childhood B-lineage acute lymphoblastic leukemia (ALL), and it might be associated with a poorer prognosis.OBJECTIVE: To present a case of oligoclonality based on the detection of IGH gene rearrangements in a patient with ALL and the correlation of the results with those of flow cytometry immunophenotyping and chimerism quantification.PATIENT AND METHODS: 26 years old female, pre-B ALL diagnosed in her childhood, in relapse after autologous and allogeneic HLA-identical unrelated stem cell transplantation (SCT). Immunophenotyping was done by multiparametric flow-cytometry, chimerism quantification was performed using fluorescent in situ hybridization (FISH) for the sex chromosomes, and IGH gene rearrangements were detected by nested-PCR revealed by capillary electrophoresis. Disease associated leukocyte lineages (CD19+, CD19+CD34+ and CD19+CD34−) were purified using immunomagnetic technology.RESULTUS: Flow-cytometry analysis in PB and BM samples at diagnosis showed expression of CD45 (weak), CD34, CD38, CD10, CD19, CD20, CD22, CD66, CD79acyt, TdT and aberrant expression of CD33, with a detectable clonal IGH rearrangement. At relapse, two distinct CD19+ cell populations were revealed from BM samples: one immature (CD34+, 15% of the total leukocytes) with similar phenotype at diagnosis, and another one mature (CD34−, 10% of the total leukocytes). FISH analysis showed mixed chimerism (MC)(31% recipient) in BM samples and complete chimerism (CC) in PB samples. Molecular analysis showed three different clones in BM and a polyclonal pattern in PB. In order to increase sensitivity, CD19+ cells were isolated from BM and PB. Cells selected from BM showed MC (98,5% recipient) and the three clonal IGH gene rearrangements while those from PB showed CC and a polyclonal pattern. Further studies exhibited persistence of the CD19+CD34+ population and significant reduction of the mature CD19+CD34− cells. A persistent three clone pattern was present in BM samples. In order to clarify the origin of the different IGH gene rearrangements, two consecutive immunomagnetic selections, one with CD19+ and other with CD34+ antibodies, were performed from BM samples to purify both CD19+CD34+ and CD19+CD34− populations. CD19+CD34+ cells showed all the three IGH clones and MC (88% recipient). Moreover, CD19+CD34− cells showed a monoclonal pattern with an unique peak, not detected in previous studies, and CC (Table 1).CONCLUSIONS: The clonal diversity of IGH gene rearrangements detected at relapse after SCT was generated from the original malignant CD34+ clone, possibly due to clonal evolution, and seems to be associated with the poor outcome of this case. After multiple therapy modalities, the CD19+CD34+ cells showed resistance to treatment. Surprisingly, the CD19+CD34− cells showed a new clonal rearrangement although its donor origin confirmed its reactive nature in the context of SCT. This observation has relevance in the further follow up and minimal residual disease detection in this case. [Display omitted]

Heterogeneous loss of the Y chromosome in leukocyte lineages of donor origin after stem cell transplantation

Heterogeneous loss of the Y chromosome in leukocyte lineages of donor origin after stem cell transplantation

KSHV targets multiple leukocyte lineages during long-term productive infection in NOD/SCID mice.

To develop an animal model of Kaposi sarcoma-associated herpesvirus (KSHV) infection uniquely suited to evaluate longitudinal patterns of viral gene expression, cell tropism, and immune responses, we injected NOD/SCID mice intravenously with purified virus and measured latent and lytic viral transcripts in distal organs over the subsequent 4 months. We observed sequential escalation of first latent and then lytic KSHV gene expression coupled with electron micrographic evidence of virion production within the murine spleen. Using novel technology that integrates flow cytometry with immunofluorescence microscopy, we found that the virus establishes infection in murine B cells, macrophages, NK cells, and, to a lesser extent, dendritic cells. To investigate the potential for human KSHV-specific immune responses within this immunocompromised host, we implanted NOD/SCID mice with functional human hematopoietic tissue grafts (NOD/SCID-hu mice) and observed that a subset of animals produced human KSHV-specific antibodies. Furthermore, treatment of these chimeric mice with ganciclovir at the time of inoculation led to prolonged but reversible suppression of KSHV DNA and RNA levels, suggesting that KSHV can establish latent infection in vivo despite ongoing suppression of lytic replication.

Isolation of large numbers of human mesenchymal stem cells from discarded filters after bone marrow harvests: Implications for therapy

12501 Background: Bone Marrow (BM) is an excellent source of Mesenchymal Stem Cells (MSCs) which can be expanded and used clinically. There is a growing evidence that MSCs can promote engraftment and reduce Graft versus Host Disease (GVHD). Bone marrow harvests are passed through 850μ, 500μ and 200μ filters to trap bony spicules and clots before infusion into patients. We hypothesize that the filters would also trap a significant number of MSCs which can be useful clinically after isolation and possible expansion. Methods: Bone marrow collection kits were obtained after informed consent of the donor (n = 11). Specimens were obtained in the course of scheduled bone marrow harvests. Cells were isolated and cultured from each portion of the device. Results: An average of 1×109 total mononuclear cells was obtained from the discarded marrow collection devices. Cells isolated in this experiment conform to published data regarding MSCs. The immunophenotype was CD44+, CD73+, CD90+, CD105+, CD14−, CD34−, CD45−, HLA-DR−, negative for leukocyte lineage specific antigens and positive for Prolyl-4-Hydroxylase. The cells were morphologically consistent with published data, being bilaterally symmetrical and forming conspicuous fibroblastoid colonies which readily grew to confluence and followed differentiation pathways to both adipose osteoid tissue. Fresh cells from the kits may also contain a precursor for MSCs that is CD90− and CD73−. Sorting for this precursor population yielded colony forming units consistent with MSCs. Conclusion: This represents a novel strategy for obtaining “healthy” material for potential therapy and study. No significant financial relationships to disclose.

Regulation of Apoptosis by Gram-Positive Bacteria: Mechanistic Diversity and Consequences for Immunity

Apoptosis, or programmed cell death (PCD), is an important physiological mechanism, through which the human immune system regulates homeostasis and responds to diverse forms of cellular damage. PCD may also be involved in immune counteraction to microbial infection. Over the past decade, the amount of research on bacteria-induced PCD has grown tremendously, and the implications of this mechanism on immunity are being elucidated. Some pathogenic bacteria actively trigger the suicide response in critical lineages of leukocytes that orchestrate both the innate and adaptive immune responses; other bacteria proactively prevent PCD to benefit their own survival and persistence. Currently, the microbial virulence factors, which represent the keys to unlocking the suicide response in host cells, are a primary focus of this field. In this review, we discuss these bacterial "apoptosis regulatory molecules" and the apoptotic events they either trigger or prevent, the host target cells of this regulatory activity, and the possible ramifications for immunity to infection. Gram-positive pathogens including Staphylococcus, Streptococcus, Bacillus, Listeria, and Clostridia species are discussed as important agents of human infection that modulate PCD pathways in eukaryotic cells.

A transient microenvironment loaded mainly with macrophages in the early developing human pancreas

We have previously shown that the human developing pancreas, as a tissue under construction and remodeling, is composed of epithelial ducts and differentiated endocrine cells surrounded by mesenchyme. The physiologic importance of resident tissue leukocytes, expected to enter through the mesenchyme in remodeling functions, prompted us to investigate human developing pancreases for the presence of leukocyte lineages and for expression of cytokines and receptors involved in their recruitment and differentiation. Immunohistochemistry studies were performed on 69 human, paraffin-embedded pancreases at 6-12 weeks of development (WD). Cytokines and receptor transcripts were monitored by reverse transcription (RT)-PCR, by immunohistochemistry when antibodies were available or by in situ hybridization (ISH). We show that numerous cells expressing CD45RA, HLADR and CD68 antigens are cellular components of the mesenchyme of all the pancreases at 6-12 WD. So-called constitutive chemokines (SLC (CCL19), stromal-derived factor 1 (SDF1) (CXCL12)) and a macrophage-specific growth/survival factor, colony-stimulating factor 1 (CSF1), were detected in epithelial duct cells. Both epithelial and mesenchymal cells expressed chemokine receptors, suggesting a role in leukocyte recruitment and possibly in early pancreatic development. In conclusion, we demonstrated the presence of CD45RA resident leukocyte-derived lineages, mostly macrophages, in the early human pancreatic mesenchyme. These cells may have migrated in the tissue through the vascular system, attracted by constitutively expressed chemokines, and locally surviving through CSF1 signaling. The role of macrophages in epithelium/mesenchyme interaction-mediated pancreatic development remains to be demonstrated.

806. Immunologic Improvement after Gene Therapy in 3 Preadolescents with X-Linked Severe Combined Immunodeficiency (XSCID)

XSCID results from mutations in the IL2RG gene encoding the common gamma chain (|[gamma]|c) shared by several cytokine receptors. Gene therapy as primary treatment for XSCID infants can restore immunity, but 2 teenagers with XSCID did not benefit from gene transfer to autologous bone marrow CD34+ cells. We used retrovirally transduced autologous peripheral mobilized CD34+ cells to treat 3 XSCID preadolescents 10-14 years old with immunodeficiency despite haploidentical bone marrow transplants (BMT). After 6-24 m we found selective gene marking of T cells in all 3 patients, with variable evidence of immunologic improvement. Prior to gene therapy, they had growth failure, frequent infections, diarrhea, T lymphocytopenia, and poor T, NK and B cell function. Each received 30-40 million cells/kg transduced ex vivo with GALV-MFGS-|[gamma]|c. Patient 1 (P1) had a poly-A addition signal mutation allowing residual |[gamma]|c function and had rejected 4 BMTs. At 24 m post gene therapy P1 had provirus detected by quantitative PCR in 4.3% of T cells and 0.1% of both B and myeloid cells. In P2 proviral marking at 18 m was 110% (or average copy number of 1.1), 5% and 0.1% in T, B and myeloid cells, respectively. P3 at 6 m had 22% marking in T cells, with low levels in other leukocyte lineages. CD4+ T cell counts in all patients have increased, but remain below the normal range. P1 has experienced improvement in well-being and resolution of lifelong diarrhea, abdominal distention and rashes; he has not had infections except for an otitis externa 12 m after treatment. A 0.5 cm submandibular nodule consistent with a lymph node arose 6 m post gene therapy and has not changed. After gene therapy P2 has had less frequent diarrhea and respiratory infections. At 6 m post treatment his T cells developed normal proliferative responses to mitogens and Candida antigen. At 12 m, P2 acquired detectable CD4+CD45RA+ T cells and T cell receptor excision circles, indicating new thymic output; donor chimerism assay showed autologous T cell expansion from 49% before gene therapy to 87% at 12 m and beyond. P3 has also reported improved well-being, exercise tolerance and appetite at 6 m; he has had increases in T cell number and proliferative responses to mitogens. Analysis of retroviral insertion sites in P1 and P3 consistently showed polyclonality. T cells of P2 had an oligoclonal pattern by LAM-PCR, but linker-mediated PCR yielded a wide variety of insertions. Furthermore, both V|[beta]| TCR usage and spectratyping showed increasing diversity after gene therapy. Proviral insertions near LMO2, implicated in European XSCID leukemia cases, have not been identified. Our preliminary results suggest that gene therapy may benefit some XSCID patients who have failed previous BMT treatment. Prior production of allogeneic T cells in P2 may have helped to preserve his thymic function. Further follow-up will establish long-term safety, efficacy and indications for XSCID gene therapy in preadolescent subjects with XSCID.

Tissue Distribution of Fetal Liver Cells Following in Utero Transplantation in Mice

Transplantation of hepatic stem cells in utero has been advanced as a potential clinical approach to a variety of diseases, including deficiencies of coagulation factors. Although syngeneic transplantation has met with some success, consideration needs to be given to the potential for transplanted cells to colonize nontarget tissues. Liver cells were harvested from Rosa26 embyros at embryonic age 12.5 days postconception (pc) and transplanted into the peritoneal cavity of syngeneic recipients in utero. Tissues were harvested from tissue recipients at various time points ranging from 1 to 328 days pc, and tissues were stained for beta-galactosidase to identify the existence of cells derived from Rosa26 donors. Beta-galactosidase-positive cells were found in the lung, liver, and brain as early as 20 days pc and through 328 days pc. Positive cells in these tissues existed as islands of cells that were morphologically similar to hepatocytes. In the spleen, individual beta-galactosidase-positive cells of both leukocytic and erythrocytic lineages were present, and suggest that hematopoietic cells were transferred to recipients along with hepatocytes. The lack of an inflammatory response to the beta-galactosidase-positive cells suggests that the donor cells were immunologically tolerated. In summary, the possibility that cells administered in utero may inadvertently colonize nontarget tissues suggests that clinical application of this method will need to be approached with diligence.

The Different Dynamics of Chimerism Evolution Determines the Success of Myeloablative, Reduced Intensity Conditioning and T-Cell Depleted Allogeneic Stem Cell Transplantation.

Background: The dynamics of chimerism evolution determines the success of allogeneic stem cell transplantation (SCT). Several factors such as the intensity of the conditioning regimen, the T-cell content of the graft or the GVHD prophylaxis, influence the degree of chimerism after SCT. Objective: To evaluate the dynamics of chimerism after different SCT settings (ablative, reduced intensity conditioning -RIC- and T-cell depleted -TCD-) and its influence in the success of the procedure.Patients and Methods: The study includes 68 SCT: 32 ablative (including 7 from HLA matched unrelated donors -UD-), 19 RIC and 17 TCD (including 8 from haploidentical donors and 2 from UD with 1 HLA disparity). Chimerism analysis was performed by FISH for the sex chromosomes or STR-PCR (sensitivity 1 Samples obtained on days +30, +100, +180, +365 and once a year thereafter, included bone marrow (BM) and peripheral blood (PB). Moreover, chimerism was analyzed in PB and leukocyte lineages (T lymphocytes CD3+, B lymphocytes CD19+ and myeloid cells CD15+ isolated (purity >95%) by immunomagnetic means, AutoMACS, Miltenyi Biotec), every 2 weeks, starting on day +15 (except in ablative), and until complete chimerism (CC) was achieved. Results of chimerism follow-up were censored once the diagnosis of relapse or rejection was established.Results: The incidence (% patients) of mixed chimerism (MC) on day +30 (ablative: BM 27%, PB 15%; RIC: BM 40%, PB 41%, CD3 40%; TCD: BM 31%, PB 33%, CD3 54%), as well as its dynamics (MC on day +100: ablative BM 8%, PB 4%; RIC BM 8%, PB 15%, CD3 22%; TCD BM 20%, PB 40%, CD3 37%) were different in the three SCT settings. All except 2 CD15 samples analyzed showed CC. Moreover, the percentage of recipient cells (%R) was significantly higher after RIC and TCD than after ablative SCT, as well as in T lymphocytes than in BM or PB (7/8 cases with simultaneous studies showed MC in T lymphocytes and CC in PB). All RIC SCT evolved to CC by day +180 while TCD SCT showed persistent MC (2 patients with stable MC after one year). The incidence of rejection was greater after RIC (2/19) and TCD (4/17) than after ablative SCT (2/32). All these patients showed MC, mainly in T lymphocytes, which allowed early diagnosis and successful treatment with immunosuppression withdrawal and donor leukocyte infusion. Patients with CC in PB/T lymphocytes on day +30 had a higher incidence of GVHD>I than those with MC. In the present series, however, a relationship between chimerism and relapse, disease free survival or overall survival, was not observed.Conclusions: SCT with greater incidence of MC (RIC and TCD) favor immune tolerance between donor and recipient which reduces the risk/severity of GVHD at the expense of a higher incidence of graft rejection.

Human Cytomegalovirus Inhibits Granulopoiesis Via Direct Infection and Inducing Apoptosis.

Human cytomegalovirus (HCMV) infection can cause delayed leukocyte recovery after bone marrow transplantation and often associated with suppression of granulocyte/macrophage progenitor. Leukocyte lineage may be one of the major sites of HCMV infection. However, whether HCMV can interfere with CFU-GM formation and induce apoptosis in granulocyte/macrophage progenitor have not been well investigated. Human bone marrow mononuclear cells (Ficoll), promyelocyte cell line HL-60 and HCMV AD169 strain were co-cultured. Each bone marrow specimen was HCMV DNA and HCMV IgM negative by PCR and ELISA test. Our results showed that HCMV significantly inhibited the formation of CFU-GM as shown in two different concentrations of viral infection groups: 139.26 ± 5.42 (2×105pfu/ml), and 124.19 ± 8.82 (2×106pfu/ml) (colonies/2×105cells/ml, n=26). These were significant differences compared with the blank control group (P<0.01, P<0.05) respectively. HCMV also significantly inhibited the growth of HL-60 cells in three different concentrations of viral infection groups (101pfu/ml, 102pfu/ml, 103pfu/ml). After incubation for 7 days, viability cells in control group and each infection groups (n=20) were 96%, 83%, 73%, and 64%, showing that HCMV infection decreased the viability of HL-60 cells in a dose-dependent manner. The apoptotic effect was also investigated by Annexin V assay using flow cytometry. The percentage of Annexin V -positive cells were 19.60 ± 1.63 (in group of 101pfu/ml) (P<0.05), 28.70 ± 2.61 (102pfu/ml) (P<0.05), and 36.3 ± 2.57 (103pfu/ml) (P<0.01), compared with control group 3.96 ± 1.75 (n=8). The apoptotic cells were further confirmed by morphologic observation and DNA ladder formation. Furthermore, HCMV DNA was positive in HL-60 cells and cells of CFU-GM measured by PCR and IS-PCR analysis respectively. These were negative in blank and mock control groups. Our data demonstrated that: (1) HCMV AD169 strain inhibited the growth of HL-60 and CFU-GM formation in a dose-dependent manner; (2) HCMV transcription occurred in HL-60 and CFU-GM cells; and (3) This virus induced apoptosis in HL-60 cells. HCMV may have an inhibiting effect on granulopoiesis via direct infection and inducing apoptosis on myeloid progenitors.

Is the upregulation of bradykinin B2 receptors by TGF-β1 one of the missing pieces in the “airway hyperresponsiveness” puzzle?

transforming growth factor (TGF)-β1 belongs to the TGF-β family of proteins corresponding to a set of pleiotropic secreted signaling molecules with unique and potent immunoregulatory properties ([10][1]). TGF-β1 is produced by every leukocyte lineage, including lymphocytes, macrophages, and