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Biomedical subjects

F Facchetti

Publications and source records attributed to F Facchetti.

At least 109 records · Page 6Linked to original sources
PubMed1990

Inflammatory pseudotumor of lymph nodes. Immunohistochemical evidence for its fibrohistiocytic nature.

Five cases of inflammatory pseudotumor (IPT) of the lymph node were investigated by means of light microscopy and immunohistochemistry to elucidate its cellular composition. The IPT is composed of a proliferation of spindle cells, inflammatory cells, and small vessels, forming high and poor cellular areas. Many spindle cells correspond to activated histiocytes as they coexpress vimentin and macrophage-associated markers; they are intermingled with vimentin-positive fibroblasts and variable numbers of vimentin- and actin-positive myofibroblasts. This mixed-cell proliferation invades and/or destroys medium- and large-sized vessels in all cases. This study indicates that the spindle cell proliferation, identified as histiocytic and fibroblastic in nature, represents the main component of the nodal IPT. We speculate that release of cytokines by the activated histiocytes may result in the development of the complex histopathologic aspects of this inflammatory process and, if inappropriate, may represent the underlying pathogenic mechanism.

Actins↗
PubMed1990

[Epidermal nevus syndrome with multiple vascular hamartomas and malformations].

The authors described a 39 year old woman affected by epidermal nevus syndrome, with cutaneous (verrucous epidermal nevus), skeletal (thoracolumbar levoscoliosis and frontal bossing) and ocular (papillar coloboma and coroideal nevus) defects. Moreover the patient presented vascular malformations and hamartomas: lymphangioma circumscriptum of the mammary area, left peroneal Gorham's disease, artero-venous acral tumour of the left foot and multiple artero-venous shunts of the lower limbs. Since puberty, hemodynamic modifications have caused pseudo-Kaposi of Bluefarb-Stewart of legs and feet and malleolar painful ulcers. Solomon's epidermal nevus syndrome is an heterogeneous entity. In our opinion, this is the first case report with a severe vascular involvement.

Abnormalities, Multiple↗
PubMed1989

Plasmacytoid monocytes (so-called plasmacytoid T cells) in Hodgkin's disease.

The occurrence and distribution of plasmacytoid monocytes (so-called plasmacytoid T cells) were investigated immunohistochemically in 40 cases of Hodgkin's disease. Large numbers of plasmacytoid monocytes were found in all cases of lymphocyte predominance, nodular sclerosing, and mixed cellularity Hodgkin's disease, characterized by a minor degree of architectural effacement. They occurred at the periphery of lymphoid aggregates which mimic the composite nodule of the reactive lymph node and which contained Reed-Sternberg cells and their variants. Despite some immunophenotypic similarities, no further arguments were found to support a relationship between plasmacytoid monocytes and Reed-Sternberg cells. We conclude that plasmacytoid monocytes represent one of the monocyte-derived cells that contribute to the cellular reaction in Hodgkin's disease.

B-Lymphocytes↗
PubMed1989

Plasmacytoid monocytes (so-called plasmacytoid T cells) in granulomatous lymphadenitis.

Immunohistochemical evidence that the plasmacytoid T cell is closely related to the blood monocyte has been reported, and the term plasmacytoid monocyte has been proposed to describe this cell. The present study was undertaken to analyze the presence and distribution of plasmacytoid monocytes in human reactive lymph nodes showing epithelioid cell reactions. Numerous plasmacytoid monocytes (detected by a panel of monoclonal antibodies) were found in the majority of the lymph nodes studies, usually in close topographical association with epithelioid cells and multinucleated giant cells. The present findings suggest that plasmacytoid monocytes may give rise to epithelioid cells. This is further supported by the ultrastructural similarities between plasmacytoid monocytes and plasmacytoid epithelioid cells, a cell type that has been identified previously in granulomas and considered a direct precursor of the classical epithelioid cell.

Granuloma↗
PubMed1989

Anti-high endothelial venule monoclonal antibody HECA-452 recognizes plasmacytoid T cells and delineates an "extranodular" compartment in the reactive lymph node.

So-called plasmacytoid T cells represent a subset of monocyte related cells, which share with endothelium the CD36+ CD11b- (OKM5+ OKM1-) phenotype. The reactivity of plasmacytoid T cells with rat monoclonal antibody HECA-452, highly specific for high endothelial venules, was analyzed in reactive lymph nodes. In all cases, HECA-452 not only labelled the endothelium of high endothelial venules, but also strongly reacted with singular and clustered plasmacytoid T cells. The HECA-452 positivity for high endothelial venules and plasmacytoid T cells visualized a lymph node compartment extending from the subcapsular sinus to the corticomedullary junction. This compartment surrounded the composite nodule and was designated the "extranodular" compartment. The co-occurrence of plasmacytoid T cells and high endothelial venules in this extranodular compartment, together with their immunophenotypical similarities, may be indicative of functional co-operations.

Antibodies, Monoclonal↗
PubMed1989

Plasmacytoid monocytes (so-called plasmacytoid T-cells) in Kikuchi's lymphadenitis. An immunohistologic study.

Three cases of Kikuchi's lymphadenitis were studied immunohistochemically on paraffin-embedded material in order to compare the plasmacytoid monocyte aggregates occurring in this disorder with plasmacytoid monocyte clusters in nonspecific reactive lymphadenitis. One of the cases was also analyzed on frozen material. In Kikuchi's lymphadenitis, plasmacytoid monocytes expressed the CD38 and LN1 antigens in addition to their monocyte/macrophage antigens found in nonspecific reactive lymph nodes. These plasmacytoid monocyte aggregates contained large numbers of Mac387+ lysozyme+ macrophages, scattered HLADR+ dendritic cells, and high numbers of CD8+ T-lymphocytes. Collections of T-immunoblasts or areas of necrosis were observed within these aggregates. The authors speculate that the histologic feature of Kikuchi's lymphadenitis is the morphologic substrate of a T-cell-mediated cytotoxic immune reaction occurring in plasmacytoid monocyte aggregates and resulting in plasmacytoid monocyte damage and necrosis.

Adult↗
PubMed1989

Hepatocellular transferrin receptor expression in secondary siderosis.

We investigated the hepatocellular transferrin receptor expression in 55 human liver specimens with secondary siderosis, with an indirect immunoperoxidase technique on frozen sections using 3 monoclonal anti-transferrin receptor antibodies. For comparison, specimens were also stained with the monoclonal antibody BK19.9, recognizing an antigen which is biochemically similar to the transferrin receptor, and with a monoclonal antibody against the epidermal growth factor receptor. The degree of iron overload was estimated semi-quantitatively, taking into account hepatocellular and Kupffer cell iron deposition. In 47 out of 55 specimens hepatocellular transferrin receptor expression was present. The positivity was predominantly localized on hemosiderin-free hepatocytes. With increasing hepatocellular iron deposition, the proportion of cases with absent transferrin receptor immunoreactivity increased. This supports the previously reported disappearance of hepatocellular transferrin receptor expression in primary hemochromatosis cases with severe iron deposition. However, the transferrin receptor negative cases included four specimens in which Kupffer cell iron deposition clearly exceeded hepatocyte iron load. This finding suggests that in addition to hepatocellular iron load other factors may regulate the expression of parenchymal transferrin receptors in iron overload diseases. These may include plasma levels of various iron sources and/or Kupffer cell iron load. The iron deposition did not influence the staining of the hepatocellular epidermal growth factor receptor nor the Kupffer cell staining by the BK19.9 antibody. This confirms the specificity of the findings concerning the behaviour of the transferrin receptor in secondary siderosis.

Antibodies, Monoclonal↗
PubMed1989

Binding of biotin to hepatitis B surface antigen: a possible pitfall in immunohistochemistry.

We report on the binding of biotin, and hence of biotinylated antibodies and lectins, to ground glass hepatocytes and liver cell membranes in chronic hepatitis B viral infection. This binding is of low affinity, and was proved to be directed at the hepatitis B surface antigen, presumably at its disulfide bonds. To avoid false-positive results, this affinity should be considered in the interpretation of immunohistochemical stainings of hepatitis B virus-infected liver tissue with biotinylated reagents.

Antibodies, Monoclonal↗
PubMed1988

Plasmacytoid T cells in a case of lymphocytic infiltration of skin. A component of the skin-associated lymphoid tissue?

A case of cutaneous lymphocytic infiltration with large numbers of plasmacytoid T cells (PTC) is reported. Lectin staining and immunohistological analysis revealed that PTC and cutaneous dendritic cells showed a similar expression of concanavalin A, LN2, and MT1. Moreover, differences in TAL 1B5 and S-100 expression were noted. From these findings we suggest that PTC may occur in the skin as a component of the skin-associated lymphoid tissue.

Adult↗
PubMed1988

Phenotypic characterization of inflammatory cells in phlyctenular eye disease.

Phlyctenular conjunctival biopsy specimens obtained from seven patients presenting with ulcerated limbal phlyctens were examined with routine histology and immunohistochemistry using a panel of monoclonal and polyclonal antibodies and immunoperoxidase techniques. Large numbers of mononuclear phagocytes, dendritic Langerhans cells and polymorphonuclear leukocytes and moderate numbers of T-lymphocytes were observed in the epithelium. This infiltrate was most intense at the basal epithelial layers which expressed HLA-DR antigens. The underlying stromal inflammatory infiltrate was organized as perivascular cuffs and a scattered subepithelial infiltrate, and consisted of many mononuclear cells and poly-morphonuclear leukocytes. Among the mononuclear cells, monocyte derived cells dominated and included monocytes macrophages and dendritic cells. T-lymphocytes were present in moderate numbers, whereas B-lymphocytes and plasma cells, mostly of IgA class, were infrequent. These findings provided in situ immunohistochemical evidence that phlyctenular eye disease is the result of delayed type hypersensitivity immune response in which monocytes and monocyte derived cells play a central role.

Antibodies, Monoclonal↗
PubMed1988

Plasmacytoid T cells: a cell population normally present in the reactive lymph node. An immunohistochemical and electronmicroscopic study.

Plasmacytoid T cells (PTCs) are medium-sized cells characterized by abundant rough endoplasmic reticulum. They occur in the thymic-dependent area in human lymph nodes. PTCs are hardly identified in routinely stained sections. We studied their occurrence in 100 reactive lymph nodes with the use of monoclonal antibodies MB2, MT1, LN1, LN2, reactive on paraffin-embedded tissue, and with electron microscopy in nine selected cases. PTCs strongly reactive with MT1 and LN2 were found in 87 of 100 lymph nodes. They were observed in clusters, loose aggregates, and as singular cells. An association between PTCs, postcapillary venules, small T lymphocytes, and interdigitating reticulum cells (IDRCs) was found. Our results indicate that PTCs are normally present in the human lymph node. Their immunophenotype suggests a relationship with a monocyte/macrophage lineage, but does not rule out a T cell origin. If the various distribution patterns represent the morphologic substrate of functional stages of PTCs it can be assumed that PTCs play a role in T cell-mediated immune response.

Adolescent↗
PubMed1988

Immunomorphological analysis of the role of blood vessel endothelium in the morphogenesis of cutaneous Kaposi's sarcoma: a study of 57 cases.

In this study we report the histopathological features in a series of 88 biopsies from patients with cutaneous Kaposi's sarcoma; immunohistochemical examination for Factor VIII related antigen has been carried out on frozen and paraffin-embedded sections. The patient groups comprised 50 elderly patients, seven of whom were immuno-compromised, six patients with AIDS and one patient who had received a renal allograft. The findings were similar in these three groups. Histological staging was carried out with subdivision into stage I--patches characterized by angiomatoid and glomeruloid structures; stage II--plaques characterized by confluence of angiomatoid and glomeruloid structures and with spindle cells; and stage III--nodules in which the spindle cells were proliferative and frankly sarcomatous. Factor VIII related antigen was demonstrated in the central vessels of glomeruloid lesions whilst the surrounding vascular network contained both antigen-negative and antigen-positive vessels; in stage II and III lesions the spindle cells were consistently positive only in frozen section material. The findings were similar in the three patient groups. Our results suggest that Kaposi's sarcoma evolves from stage I through to stage III, that both blood vessels and lymphatic vessels are involved in the vascular proliferation and that the spindle cells are derived from vascular endothelium.

Acquired Immunodeficiency Syndrome↗
PubMed1988

Plasmacytoid T cells. Immunohistochemical evidence for their monocyte/macrophage origin.

To elucidate the lineage of plasmacytoid T cells, their immunophenotype was studied in reactive lymph nodes with a broad panel of monoclonal antibodies. Plasmacytoid T cells expressed several myelomonocytic markers, and almost all markers highly selective for macrophages. They lacked granulocyte-associated and B or T lymphocyte-associated antigens. These results provide strong evidence that plasmacytoid T cells are of monocyte lineage.

Antibodies, Monoclonal↗
PubMed1986

HBsAg, HBcAg and delta-Ag in liver tissue: simultaneous visualization in a single tissue section by triple immunostaining.

The distribution pattern of HBsAg, HBcAg and Delta-Ag was investigated by immunohistochemistry in a series of paraffin embedded liver tissue specimens from 45 subjects with serum HBsAg and anti-Delta antibody positivity. An indirect immunoperoxidase technique was used. Stains for HBsAg, HBcAg and Delta-Ag were alternatively carried out on serial tissue sections and, for the first time, consecutively in a single section (triple immunostaining). Simultaneous presence of all antigens occurred in 7 out of 45 cases, and of two antigens (HBsAg and Delta-Ag) in the remaining 38. Two antigens (either HBsAg and HBcAg or HBcAg and Delta-Ag) could also be shown in the same cell. A series of new observations was forwarded by the successful application of triple immunostaining in the present series: 1) high frequence of simultaneous presence of HBcAg and Delta-Ag (7 out of 45 cases = 16%); 2) cytoplasmic localization of Delta-Ag; 3) localization of HBcAg on the cell membrane of HBsAg positive Ground-Glass (G-G) hepatocytes; 4) Ground-Glass appearance of hepatocytic cytoplasm associated with exclusive content of HBcAg (HBcAg-Ground-Glass: a new variant of G-G-hepatocytes).

Antigens, Viral↗