[Nasal polyps: comparative immunological study of polyps with different histopathologic types]. / I polipi naso-sinusali: studio immunoistologico comparativo di formazioni con differente tipologia istopatologica.

Cellular Infiltrate as well as class I and II HLA molecule expression, on 22 nasal polyps and on 12 samples of corresponding hypsilateral mucous membrane were studied by means of immuno-histological methods. These nasal polyps were classified according to their histopathological structure. Five polyps, with a fibrous connective core infiltrated by cells of the monocyte-macrophage lineage, were classified mixed. The remaining seventeen polyps were characterized by the presence of central oedematous connective tissue infiltrated almost exclusively by eosinophils and either contained (glandular type) or did not contain (oedematous type) glands. A comparative study of different types of nasal polyps and corresponding hypsilateral nasal mucous membranes was carried out on atopic and non-atopic patients. No correlation between atopic status and polyp presence or polyp typology was found. On the other hand, different polyp types appear to have a structural correlation with the corresponding hypsilateral mucous membrane regarding infiltrate cell type, oedematous or fibrous connective tissue presence and expression of on HLA antigen positivity pattern. The characteristic histological structure of hypsilateral mucous membranes in patients with different types of polyps appeared to be brought about by a multifactorial etiology involving mucosal hyperreactivity. Lastly, both polyps and parapolypal nasal mucous membranes were found to be infiltrated mainly in the peripheral subepithelial connective tissue by lymphocytes (55%) as well as by other leukocyte types. The presence of growth factors capable of enhancing an increase of fibroblasts, endothelial cells, together with focal distrupture on the basal membrane, might well be a general mechanism responsible for polyp sprouting.

[Expression of HLA-DR, DP, DQ antigens in fibrous sino-nasal polyps]. / Espressione di antigeni HLA-DR, DP, DQ, in polipi naso-sinusali di tipo fibroso.

In the last years nasal polyps have been studied by several authors with different methodologies; however, their etiology is still unclear. In this paper we have analyzed in four nasal polyps of fibrous type, the HLA class II (HLA-DR, DP, DQ) molecule expression by means of immunohistochemical techniques (immunoperoxidase and immunophosphatase). A strong inflammatory cell infiltration, a percentage increase of both HLA-DR+ and HLA-DQ+ cells (normal nasal mucous membrane stroma infiltrating cells: DR+ < 40%, DP+ < 2%, DQ+ < 3%; fibrous polyps infiltrating cells: DR+ = 68%, DP+ < 2, DQ+ = 7%) as well as a clear positivity for DR expression of both surface and glandular epithelia were observed in all polyps. Furthermore, in the stalk area of one of the studied polyps DR+DQ+ cells with macrophagic features and having tight. connections with the vessels were observed. The scanty vascularization with the presence of activated mononuclear and mast cells might be responsible for polyp growth by locally producing an anomalous concentration of growth factors.

[Immunohistochemical study of the nasal mucosa of patients with fibrous polyps]. / Studio immunoistochimico della mucosa nasale in pazienti con poliposi di tipo fibroso.

Nasal polyps constitute a common pathology, but their etiology is not yet clear. In the present report, by means of immunohistochemical methods, both cell infiltrate and HLA-DR molecule expression were analysed in nasal mucous membrane fragments biopsied in the vicinity of fibrous polyps. Both surface and gland epithelia were positive for HLA-DR antigens in all sample whereas the epithelium of control nasal mucous membranes appeared to be negative. In addition only little delimited portions of the basement lamina seemed disrupted by an intense traffic of infiltrating cells. The poor venous drainage, the presence of activated mononuclear and mast cells capable of releasing soluble growth factors, together with basal lamina interruptions, might be factors for polyp sprouting.

[Analysis of the cellular infiltrate and epithelial class I and II molecular expression in edematous type nasal polyps]. / Analisi dell'infiltrato cellulare e della espressione epiteliale di molecole HLA di istocompatibilitá di classe I e II in polipi naso-sinusali di tipo edematoso.

Although in the last few years histopathological, immunohistochemical and immunological studies on nasal polyps have been carried out by several Authors, the etiology of these formations still remains unknown. Nasal polyps have a very characteristic structure and have been classified in three histologic types: edematous, glandular and fibrous. In the present report, 11 nasal polyps of edematous type, representing 61% of total number of collected polyps, were studied employing immunohistochemical methods. All the examined polyps were similar in histology and positivity pattern for HLA molecule expression. The edematous core appeared infiltrated (149 cells/mm.2) mainly by eosinophils (> 90%), whereas the peripheral subepithelial connective tissue contained cellular clusters (416 cells/mm2.) made up of different subsets of hematic cells (30.8% were monocytes-macrophages and 48.6% were lymphocytes largely represented by CD4+ cells). On the contrary, mast cells were quite rare (on the average 1.7 cells/mm2.) and located near T cell clusters. The epithelial positivity for HLA-DR and HLA-A,B,C molecules showed a characteristic discontinuous pattern. In the same patient, controlateral nasal mucosa showed a histological structure very similar to that of polyps. The above data suggest that the presence of polyps is the result of an inflammatory process brought about by a complex array of cellular and humoral components.

[Hematic infiltrates and the expression of HLA-DR antigens in naso-sinusoidal polyps of the fibrous type]. / L' infiltrato ematico e la espressione di antigeni HLA-DR in polipi naso-sinusali di tipo fibroso.

In this study fibrous nasal polyps, obtained from four patients, were analyzed by means of immunocytochemical methods for the presence of interstitial hematic cell infiltrate and HLA-DR molecule expression. This histologic type accounted for 36.4% of nasal polyps studied. Our results demonstrated that cells belonging to monocyte-macrophage lineage were mainly detected within fibrous and edematous zones (greater than 50%), whereas T cells were found within the subepithelial peripheral connective tissue (greater than 60%). Surface and gland epithelial cells appeared to be more intensely stained for HLA-DR molecules than nasal epithelium of normal subjects, thus indicating that the intensity of HLA-DR molecule expression correlated with the presence of a hematic cell infiltrate. Nasal polyps are a frequent pathology whose etiology has not yet been completely clarified. The present study provides additional information about the fibrous polyp structure and can support some speculations on the nasal polyp etiology.

[Pancreatic passenger leukocytes in organs obtained from cadaver donors for allotransplantation]. / I "passenger leukocytes" pancreatici in organi prelevati da donatore cadavere per allotrapianto.

In previous studies we have demonstrated that human normal pancreata were populated by interstitial mononuclear cells constituted by dendritic cells (70%), macrophages (30%) and few B cells (less than 1%). Furthermore, the endocrine parenchyma and the centroacinar cells appeared negative for the detection of HLA-A,B,C molecules. In the present report, 15 pancreata from cadaver donors were studied by means of immunohistochemical methods. 5 out of 15 organs were found to contain a larger amount of interstitial hematic cells that were constituted mainly by macrophages and B cells, together with a small percentage of granulocytes and T cells. In such "infiltrated" pancreata both endocrine parenchyma and centroacinar cells displayed a positivity for HLA-A,B,C antigens. As HLA-class I antigens have importance in allo-recognition and rejection responses, our data suggest that pre-transplant biopsies may be useful for a better evaluation of the pancreatic tissue immunogenicity.

[The Leu 7+ cell population of the human pancreas: preferential distribution and morphology]. / La popolazione cellulare Leu 7+ del pancreas umano: distribuzione preferenziale e morfologia.

Anti-Leu 7 is a monoclonal antibody which recognizes an antigenic determinant present on the surface of a subset of human large granular lymphocytes and on central and peripheral neural elements. Furthermore it cross-reacts with an intracellular protein of secretory granule matrix in neuroendocrine cells. The presence of Leu 7+ cells has been studied in lymphoid and non-hemopoietic organs. We have analyzed the Leu 7 positivity in six pancreata from cadaver donors by means of immunocytochemical methods. Leu 7+ cells were found to be also present in the exocrine portion of the organ in which they represent a nonhomogeneous cellular population. In fact, two different types of Leu 7+ elements populate the exocrine pancreas: a, Leu 7+ cells showing an intracellular granule positivity; b, Leu 7+ cells showing surface positivity. The endocrine pancreas, in contrast, contains the majority (85%) of Leu 7+ elements, belonging to the intracellular positive type only.