Neoplasms derived from plasmacytoid monocytes/interferon-producing cells: variability of CD56 and granzyme B expression.
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Aged↗
Biomedical subjects
Fabio Facchetti
Publications and source records attributed to Fabio Facchetti.
Cutting edge: differential chemokine production by myeloid and plasmacytoid dendritic cells.
To examine the different roles of myeloid dendritic cells (M-DCs) and plasmacytoid dendritic cells (P-DCs) in the induction and regulation of immune response, we have studied chemokine secretion by freshly isolated DC subsets in response to bacterial, viral, and T cell-derived stimuli. M-DCs selectively produced very high levels of the homeostatic chemokines CC chemokine ligand (CCL)17 and CCL22, while P-DCs produced very little if any. In contrast, the proinflammatory chemokine CCL3 was secreted mostly by P-DCs, whereas CCL4 and CXC chemokine ligand 8 were produced by both subsets. The selective production of CCL17 and CCL22 by M-DCs but not P-DCs was confirmed in vivo by immunohistology on human reactive lymph node sections. The high production of CCR4 ligands by M-DCs suggests their capacity to selectively recruit at sites of inflammation T cells with regulatory properties or with a Th2 phenotype, whereas P-DCs, by preferentially secreting CCR1/CCR5 ligands, would mostly recruit effector T cells and, in particular, Th1-type cells.
Cell Lineage↗
CD56bright natural killer cells are present in human lymph nodes and are activated by T cell-derived IL-2: a potential new link between adaptive and innate immunity.
Natural killer (NK) cells are innate lymphocytes that provide cytokines critical for early host defense against pathogens. One subset of human NK cells (CD56(bright)) constitutively expresses the high-affinity interleukin 2 (IL-2) receptor and produces immunoregulatory cytokines. Here, we demonstrate that CD56(bright) NK cells are present in human lymph nodes and that endogenous T cell-derived IL-2, acting through the NK high-affinity IL-2 receptor, costimulates CD56(bright) NK cells to secrete IFN-gamma. Thus, adaptive immunoregulators influence innate cytokine production, which in turn may influence the developing antigen-specific immune response. These data show a dynamic interaction between innate and adaptive human lymphocytes and emphasize the importance of studying interactions between immune components to understand the immune response as a whole.
Adult↗
IFN-producing cells respond to CXCR3 ligands in the presence of CXCL12 and secrete inflammatory chemokines upon activation.
Human natural IFN-producing cells (IPC) circulate in the blood and cluster in chronically inflamed lymph nodes around high endothelial venules (HEV). Although L-selectin, CXCR4, and CCR7 are recognized as critical IPC homing mediators, the role of CXCR3 is unclear, since IPC do not respond to CXCR3 ligands in vitro. In this study, we show that migration of murine and human IPC to CXCR3 ligands in vitro requires engagement of CXCR4 by CXCL12. We also demonstrate that CXCL12 is present in human HEV in vivo. Moreover, after interaction with pathogenic stimuli, murine and human IPC secrete high levels of inflammatory chemokines. Thus, IPC migration into inflamed lymph nodes may be initially mediated by L-selectin, CXCL12, and CXCR3 ligands. Upon pathogen encounter, IPC positioning within the lymph node may be further directed by CCR7 and IPC secretion of inflammatory chemokines may attract other IPC, promoting cluster formation in lymph nodes.
Animals↗
Severe pancytopenia and hemophagocytosis after HHV-8 primary infection in a renal transplant patient successfully treated with foscarnet.
We report the occurrence of human herpesvirus (HHV)-8 primary infection in an adult male kidney recipient. Four months after transplantation, the patient developed visceral Kaposi sarcoma, and 1 month later he presented with progressive and severe peripheral cytopenia, in the presence of a normocellular or hypercellular bone marrow (BM) with hemophagocytosis. HHV-8 was the sole pathogen detected by polymerase chain reaction either in the serum or in the BM. HHV-8 latent nuclear antigen was detected in immature progenitor cells from the BM. Immunosuppressive therapy was reduced, and the patient was treated with foscarnet for 2 weeks, leading to a dramatic normalization of blood cell counts, concomitantly with the disappearance of HHV-8 viremia. At the end of antiviral therapy, the patient received chemotherapy, and Kaposi sarcoma regressed in 2 months. Severe peripheral cytopenia may be a posttransplant complication after HHV-8 infection, for which treatment with foscarnet seems appropriate.
Antiviral Agents↗
An unusual Fc receptor-related protein expressed in human centroblasts.
Here, we report the identification of Fc receptor homolog expressed in B cells (FREB), a unique B cell-specific molecule that is distantly related to FcgammaRI (receptor I for the Fc fragment of IgG) and is encoded on human chromosome 1q, within the FcgammaR gene region. FREB has an intracellular distribution and lacks a canonical transmembrane domain. In addition, FREB lacks bona fide Fc fragment binding regions and does not bind immunoglobulins. By using specific monoclonal antibodies, we show that FREB is preferentially expressed in germinal center centroblasts, which undergo affinity maturation and class-switch recombination. Together, these characteristics indicate that FREB may have a unique role in B cell differentiation. FREB is also expressed in some B cell lymphomas, most of which have centroblast origin. Remarkably, FREB is expressed in a subset of diffuse large B cell lymphomas, providing a unique marker for the characterization of this B cell malignancy.
Amino Acid Sequence↗
Lymphomatoid allergic contact dermatitis from para-phenylenediamine.
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Adult↗
Isolated bone marrow manifestation of HIV-associated Hodgkin lymphoma.
Human immunodeficiency virus-associated Hodgkin lymphoma frequently involves the bone marrow and is usually recognized at staging after Hodgkin lymphoma diagnosis on a lymph node or other tissue biopsies, but occasionally the marrow involvement is the only apparent manifestation of disease. In the latter setting, diagnosis can be problematic. From a total of 42 patients with newly diagnosed human immunodeficiency virus-associated Hodgkin lymphoma, 22 subjects had positive marrow involvement at diagnosis; 16 of them had additional substantial histological and/or clinical extramedullary Hodgkin lymphoma. In the remaining 6 patients the bone marrow was the only site of disease at diagnosis. In all six cases, bone marrow biopsy revealed obvious lymphomatous involvement. Reed-Sternberg cells were identified both morphologically and immunophenotypically in all cases. Spared marrow tissue consistently showed fibrosis. All patients were males with a median age of 35 years (range, 31-58 years). All presented with fever, blood cytopenias, and severe CD4+ lymphocyte depletion (median, 70 cells/mm(3)). After diagnosis, all staging procedures were negative, and all patients were treated with chemotherapy. Median survival was 4 months (range, 2-118 mo). Longer survival was achieved in the patients who completed chemotherapy regimens; three subjects, however, died shortly before the full completion of chemotherapy, two of them from Hodgkin lymphoma. Isolated bone marrow HIV-associated Hodgkin lymphoma may be an underestimated condition in HIV-infected patients; in those individuals with unexplained fever and blood cytopenias, bone marrow biopsy should be performed with the aim of assessing for Hodgkin lymphoma, even in the absence of nodal and visceral lymphomatous involvement. A rapid diagnosis of isolated bone marrow HIV-associated Hodgkin lymphoma could expedite therapy.
Adult↗
Defective migration of monocyte-derived dendritic cells in LAD-1 immunodeficiency.
beta2 Integrins (CD18) are required for leukocyte migration. In fact, the absence of CD18 results in type-1 leukocyte adhesion deficiency (LAD-1). We analyzed the distribution phenotype and function of dendritic cells (DCs) in three LAD-1 patients with homozygous mutations of CD18. Two of them did not express CD18 (Patients A and C), and the other subject (Patient B) displayed reduced expression of beta2 integrins because of a missense mutation. Analysis of DCs derived from Patients A and B showed an abnormal morphology and a severe impairment in transendothelial migration and chemotactic response to CCL19/macrophage inflammatory protein-3beta, suggesting that CD18 is required for migration of monocyte-derived DCs. Nevertheless, DCs displayed normal macropinocytosis and underwent normal maturation after addition of tumor necrosis factor alpha. Finally, immunohistochemical analysis of lymph nodes from subjects B and C revealed a significant reduction in the number of factor-XIIIa(+) interstitial DCs in the interfollicular area in both patients, suggesting that CD18 plays a role in the migration of these cells in vivo.
CD18 Antigens↗
Sinonasal osteocartilaginous necrosis in cocaine abusers: experience in 25 patients.
BACKGROUND: Cocaine-induced lesions may cause extensive destruction of the osteocartilaginous structures of the nose, sinuses, and palate that mimics the clinical picture of other diseases. METHODS: From January 1991 to September 2001 25 patients with cocaine-induced midline destructive lesions were observed at the Department of Otorhinolaryngology of the University of Brescia. The diagnosis was based on physical and endoscopic evaluation, routine blood and urine analysis, radiological findings, and repeated biopsies of the nasal mucosa. Serum was analyzed by the antineutrophilic cytoplasmic antibody (ANCA) test using indirect immunofluorescence and by enzyme-linked immunosorbent assay for antibodies against proteinase 3 and myeloperoxidase. RESULTS: Septal perforation was present in all 25 patients, 16 of which (68%) also had partial destruction of the inferior turbinate. Hard palate reabsorption was observed in only six patients (24%); in two of these patients, the lesion also extended to the soft palate. Fourteen patients (56%) were positive by the immunofluorescence test (nine patients had a P-ANCA and five patients a C-ANCA pattern). Four patients (16%) with the P-ANCA pattern and all patients with the C-ANCA pattern also tested positive for anti-proteinase 3 antibodies. CONCLUSION: Any sinonasal inflammation involving the midline that persists or remains refractory to treatment may be the first manifestation of potentially lethal drug addiction. Cocaine abuse should be considered in the differential diagnosis of destructive lesions of the nasal cavity even in the presence of a positive ANCA test.
Adult↗