An unusual pattern of B-cell immunological reconstitution after allogeneic stem cell transplantation: a possible correlation with CMV reactivation?

IR after HSCT is a slow process that involves several components of the immune response, and, in allogeneic setting, it can be delayed by GvHD and immuno-suppressive therapy. Our study on IR post-HSCT included a child with FA who underwent MUD transplantation. To evaluate B, T and NK cell reconstitution and to investigate the differentiation of B lymphocyte repertoire, this patient was carefully monitored at various time points by IgHCDR3 (third complementarity determining region of the immunoglobulin heavy chain) fingerprinting and by FACS analysis. IgHCDR3 fingerprinting showed a strong oligoclonality of IgM and IgG profiles from day +60 to +180 post-transplant. CMV reactivation was present at the same time points and overlapped the clonal pattern shown in IgHCDR3 fingerprinting. Immunophenotype analysis showed early repopulation of T and NK cells following HSCT, whereas B cells increased first at one yr post-transplant. The overlapping of virus reactivation and B-cell clonal expansion seems to suggest that B lymphocytes may be involved in the CMV immunological response, at least in the early time points after HSCT when the immune repertoire is still reconstituting.

Modulation of human lung fibroblast functions by ciclesonide: evidence for its conversion into the active metabolite desisobutyryl-ciclesonide.

BACKGROUND: Ciclesonide, an inhaled corticosteroid administered as inactive compound with almost no binding affinity for the glucocorticoid receptor, is clinically effective in asthma being converted by airway epithelial cells into its active metabolite desisobutyryl-(des)-ciclesonide. AIM: To evaluate whether ciclesonide could directly modulate in vitro bronchial fibroblast functions being converted into des-ciclesonide by these pluripotent cells involved in the regulation of airway inflammation and remodelling. METHODS: Ciclesonide (0.09-9.0 microM) was added to a human adult lung fibroblast cell line (CCL-202), seeded in medium in the presence of the following cytokines and growth factors: (a) basic fibroblast growth factor (bFGF) for cell proliferation, measured by tritiated thymidine ([3H]TdR) incorporation; (b) tumour necrosis factor (TNF)-alpha, to stimulate intercellular adhesion molecule (ICAM)-1 expression and monocyte chemoattractant protein-1 (MCP-1) and eotaxin release, evaluated by flow cytometry and ELISA, respectively; (c) transforming growth factor (TGF)-beta1, for induction of alpha smooth muscle actin (alpha-SMA) protein expression and modification of the organization of alpha-SMA stress fibres, evaluated by Western blot analysis and fluorescence microscopy. RESULTS: The presence of ciclesonide in cell cultures induced a significant downregulation of: (a) bFGF-induced fibroblast proliferation and TNF-alpha-induced ICAM-1 expression, at the 0.3-9.0 microM concentrations (p<0.05); (b) TNF-alpha-induced MCP-1 release, at all the concentrations tested (p<0.05); (c) TNF-alpha-induced eotaxin release, at the three highest concentrations (0.9-9.0 microM) (p<0.05); (d) TGF-beta1-induced of alpha-SMA protein expression at the 0.3-3.0 microM concentrations, associated with a reduction in the organization of alpha-SMA stress fibres. CONCLUSIONS: These data show at cellular level an effective anti-inflammatory activity of ciclesonide on human lung fibroblasts and support the hypothesis that also these cells, in addition to airway epithelial cells, may be involved in converting the parental compound into its active metabolite in the airways.

The histamine-induced enhanced expression of vascular cell adhesion molecule-1 by nasal polyp-derived fibroblasts is inhibited by levocetirizine.

BACKGROUND: Histamine, a key chemical mediator in allergic reaction, exhibits an array of pro-inflammatory effects that include the activation of fibroblasts. The aim of this study was to evaluate whether histamine could stimulate nasal polyp-derived fibroblasts to express vascular cell adhesion molecule (VCAM)-1, a surface molecule involved in structural-inflammatory cell interaction and whether levocetirizine could inhibit this induction. METHODS: Primary nasal polyp tissue-derived fibroblasts were stimulated with histamine (10-1000 microM) or interleukin (IL)-4 plus tumor necrosis factor (TNF)-alpha (0.5-5 ng/mL) and VCAM-1 expression was evaluated by flow cytometry analysis. The inhibitory effect of the selective H1-antagonist levocetirizine (0.01-10.0 microM) on VCAM-1 expression was also tested. RESULTS: Compared with unstimulated cultures, histamine or IL-4 + TNF-alpha, at the highest concentrations tested, significantly increase VCAM-1 expression (p < 0.05). To evaluate the ability of levocetirizine to downregulate VCAM-1 expression, fibroblasts were stimulated with histamine (1000 microM) or IL-4 + TNF-alpha (5 ng/mL), in the presence of the drug (0.01-10.0 microM). The histamine-induced VCAM-1 expression was effectively inhibited by levocetirizine (0.1-10.0 microM) (p < 0.05). No effect of the drug on IL-4 + TNF-alpha-induced VCAM-1 expression was observed. CONCLUSIONS: Histamine upregulates VCAM-1 expression on nasal polyp-derived fibroblasts and this phenomenon, relevant to allergic late-phase inflammation, is effectively inhibited by levocetirizine.

V(H)3 and V(H)6 immunoglobulin M repertoire reconstitution after hematopoietic stem-cell transplantation in children.

BACKGROUND: Immune reconstitution after hematopoietic stem-cell transplantation (HSCT) occurs gradually. Thus, a variable period of immunodeficiency may be present, leading to immunomediated complications, such as graft-versus-host disease (GVHD) and opportunistic infections. METHODS: To better understand the kinetics of B-cell repertoire reconstitution in children, 49 pediatric patients were analyzed before and after transplantation by immunoglobulin (Ig) HCDR3 fingerprinting, which is a molecular technique that analyzes one of the hypervariable segments of the Ig heavy chain, which provides the amino acid residues that are essential to interact with antigens. RESULTS: In healthy donors, the CDR3 fingerprinting profile shows 16 to 20 bands, and each band corresponds to a particular length of CDR3. This situation is considered polyclonal. Patients analyzed just after transplantation show strong oligoclonality, because only a few CDR3 bands are detected within the first 3 to 6 months. CONCLUSIONS: The authors' data show a significant lag in diversification of the B-cell repertoire, which reaches the polyclonal situation of normal healthy donors approximately 6 months after HSCT. This period may vary depending on the type of transplant (autologous vs. allogeneic) and on the immunosuppressive therapy related to GVHD.

Recognition of CMV pp65 protein antigen by human CD4 T-cell lines induced with an immunodominant peptide pool.

Cellular immunity against cytomegalovirus (CMV) is essential for recovery from infection and control of viral latency. In immunocompromised hosts, this balance between CMV and cellular immunity is lost. Accordingly, restoration of the CD8 compartment specific for CMV is beneficial for immunocompromised patients. It is clear that CMV-specific CD4 cells provide helper functions facilitating long-term persistence of CD8 cells. Considering the dearth of data on CMV-specific T-helper cells, we investigated the CD4 responses to the immunodominant protein pp65 to define antigenic peptides. Such peptides were pooled and used to generate long-term T-cell lines. The lines were responsive to CMV and pp65. T cells were selected with individual peptides to produce monospecific lines for accurate definition of fine epitope specificity and to confirm human leukocyte antigen HLA-DR restriction. Furthermore, these lines lost alloreactivity, suggesting that they can be generated from the allodonor for adoptive immunoreconstitution of stem cell graft recipients.

B-cell repertoire reconstitution after hematopoietic stem cell transplantation in children evaluated by immunoglobulin heavy chain third complementarity determining region fingerprinting.

Immunodeficiency after hematopoietic stem cell transplantation leads to a high risk of opportunistic infections. We evaluated B-lymphocyte reconstitution in 36 children by heavy chain third complementarity determining region (CDR3)-fingerprinting and immunophenotypic analysis. The time necessary to return to the normal immunoglobulin heavy chain-CDR3 polyclonal situation was basically related to the type of transplant and this process did not recapitulate fetal ontogenesis.

Fibroblast-eosinophil interaction: modulation of adhesion molecules expression and chemokine release by human fetal lung fibroblasts in response to IL-4 and TNF-alpha.

In addition to be involved in airway remodelling observed in asthmatic patients, lung fibroblasts may directly contribute to pulmonary inflammation through the release of mediators and through the expression of surface molecules involved in cell-cell interaction. The aim of the study was to evaluate whether two cytokines involved in asthma pathogenesis, IL-4 and TNF-alpha, could modulate the expression of adhesion molecules (VCAM-1 and ICAM-1) and the secretion of chemokines (eotaxin and MCP-1) related to eosinophil recruitment and activation. The constitutive expression of VCAM-1 by unstimulated fibroblasts was over 2-fold lower than that of ICAM-1 (P<0.05). Significant differences were also observed in the release of chemokines by unstimulated fibroblast, the levels of eotaxin being over 17-fold lower than those of MCP-1. Stimulation of the cells with IL-4 or TNF-alpha induced a dose-dependent increase in VCAM-1, while ICAM-1 was overexpressed only in culture stimulated by TNF-alpha (P<0.05) but not in those exposed to IL-4 (P>0.05 each comparison). In contrast, a significant increase in MCP-1 and eotaxin release was observed in the presence of TNF-alpha (P<0.05) but not of IL-4 (P>0.05). These data show that two 'proinflammatory' cytokines, such as IL-4 and TNF-alpha, may have different and complementary effects on functions involved in the cross-talking between fibroblasts and eosinophils.

The antiinflammatory activity of budesonide on human airway epithelial cells is lasting after removal of the drug from cultures.

Because of its ability to conjugate extensively with fatty acids within lung cells, it has been suggested that budesonide (Bud) may have a prolonged pharmacologic activity, related to retention of the drug in airway tissues. Using human bronchial epithelial cells (HBECs) as target cells, we evaluated whether Bud could have a long-lasting inhibitory effect on ICAM-1 expression and GM-CSF release. HBECs were cultured in Bud (10 microM) or in medium alone (Ctr) for 24 hr, then extensively washed (to remove Bud) and incubated for an additional 6, 12, or 24 hr with IFN-gamma. ICAM-1 expression and GM-CSF release were then measured by flow cytometric analysis. In Ctr HBECs, IFN-gamma induced a time-dependent upregulation of ICAM-1 expression, significant at 6, 12, or 24 hr (p < 0.05, each comparison), and an increase in GM-CSF release, significant at 24 hr (p < 0.05). The inhibitory effects of Bud preexposure on IFN-gamma-induced ICAM-1 expression and GM-CSF release were then compared with those of a continuous exposure to the drug during IFN-gamma stimulation. Preexposure to Bud (1 and 10 microM) induced a significant inhibition of IFN-gamma-induced ICAM-1 expression (p < 0.05, each comparison), but lower than that observed in HBECs continuously exposed at the same Bud concentrations (p < 0.01, each comparison). In contrast, the inhibition of GM-CSF release was similar in preexposed and in exposed HBECs and statistically significant only at the highest Bud concentration tested (p < 0.05, each comparison). Thus, Bud is effective in vitro in inducing a downregulation lasting 24 hr of mechanisms involved in leukocyte recruitment.