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Biomedical subjects

M A Piris

Publications and source records attributed to M A Piris.

At least 91 records · Page 5Linked to original sources
PubMed1992

Human tonsil intraepithelial B cells: a marginal zone-related subpopulation.

AIMS: To determine if intraepithelial B cells in reactive human palatine tonsils were similar to the marginal zone cells of the spleen and Peyer's patches. METHODS: Reactive human palatine tonsils were studied using conventional methods of light microscopy, electron microscopy, and a panel of monoclonal antibodies for leucocyte common antigens. RESULTS: Clinically important numbers of marginal zone-related B cells around the mantle zone were absent in lymphoid follicles, but in the cryptal epithelium there were abundant lymphoid cells with centrocyte-like nuclei and clear cytoplasm, intermingled with macrophages and plasma cells. The immunophenotype of these intraepithelial B cells was distinctive and similar to that found in the splenic marginal zone cells (IgM+, IgD-, CD23-, CD10-, CD35+, CD21+, bc12+, KB61+). CONCLUSIONS: Intraepithelial B cells in human tonsil could represent the counterpart of the marginal zone described in Peyer's patches. Their presence within the epithelium could reflect the destination for the malignant B cells in the lymphoepithelial lesion of mucosa associated lymphoid tissue (MALT) lymphomas. Human palatine tonsil lymphoid tissue has morphological, immunophenotypic, and pathological features similar to those of MALT.

B-Lymphocytes↗
PubMed1991

Lymphocyte predominance Hodgkin's disease (nodular paragranuloma)--a bcl-2 negative germinal centre lymphoma.

Hodgkin's disease, lymphocyte predominance type (nodular paragranuloma), is of germinal centre origin and the tumour cells have a B-cell phenotype. As the T(14;18) translocation, and the subsequent expression of bcl-2 protein by germinal centre cells, is the most characteristic finding of centroblastic-centrocytic lymphoma, we have tested a series of 11 cases of lymphocyte predominance Hodgkin's disease, using Southern blot analysis for the major breakpoint region and the minor breakpoint cluster region, polymerase chain reaction with primers for the major and minor breakpoint cluster region, and immunohistological studies with a monoclonal antibody specific for the bcl-2 protein. All three techniques gave negative results in the cases of Hodgkin's disease, establishing a clear differentiation from centroblastic-centrocytic lymphoma. These findings are useful in the differential diagnosis between the two entities and raise the question of the non-clonal nature of lymphocyte predominance Hodgkin's disease.

Antibodies, Monoclonal↗
PubMed1991

Different bcl-2 protein expression in high-grade B-cell lymphomas derived from lymph node or mucosa-associated lymphoid tissue.

High-grade B-cell lymphomas, whether originated in a lymph node or in mucosa-associated lymphoid tissue (MALT), show similar morphologic traits, a fact that has fueled a long-running controversy about whether they represent different entities. They differ, however, in that some high-grade MALT lymphomas show less aggressive clinical behavior, a focal low-grade component being identified in some of them. In a search for bcl-2 protein expression, we have found a significant difference between nodal (39/48) and MALT high-grade B-cell lymphoma (1/15) (P less than 0.01). Bcl-2 gene product is an inner mitochondrial membrane protein able to give a survival advantage to B-cell lines by blocking programmed cell death. This protein is usually expressed by memory or resting B cells, most activated B cells being bcl-2 negative, except in lymph-node-originated high-grade B-cell lymphomas, which appear to be mainly bcl-2 positive. Presence of bcl-2 protein in nodal large-cell lymphomas seems to be independent of a t(14;18) translocation, only being found in 19 to 28% of these lymphomas, although it constitutes a definite difference between both tumors, suggesting the existence of different molecular genetic characteristics and pathogenesis, and is possibly related to the more aggressive clinical behavior of nodal high-grade tumors.

Cell Transformation, Neoplastic↗
PubMed1990

[Low-grade B cell gastric lymphoma originated in mucosa-associated lymphoid tissue. Relationship of tumor cells with the marginal zone and monocytoid B lymphocytes. An immunohistochemical and ultrastructural study].

Seven cases of gastric B-cell low-grade lymphomas were characterized by morphology, immunohistology and electron microscopy. All them were immunophenotyped with a panel of monoclonal antibodies against immunoglobulins and other B-cell determinants. Histologic study of gastric B-cell low-grade lymphomas showed germinal centers of lobated shape and polyclonal nature, mainly polyclonal subepithelial plasma cell (except in one case) and neoplastic interfollicular B-cells of monoclonal character. Light-chain restriction supports the neoplastic nature of gastric lymphoma of low-grade malignancy, a distinctive tumour of extranodal B-cell origin. Interfollicular B-cells share with marginal zone cells a perifollicular localization, morphology and phenotype, suggesting a possible relation between these two cellular subtypes. In two cases, the tumour appears constituted by monocytoid B-lymphocytes (MBL), which suggests a relation of tumoral interfollicular B-cells with this subpopulation.

Adult↗
PubMed1990

Cytotoxic/suppressor (CD8+, CD4-) cutaneous T-cell lymphoma with aggressive course.

A case of cutaneous cytotoxic/suppressor T-cell (CD8+, CD4-) lymphoma is reported. The tumor was characterized by its rapid growth and no response to polychemotherapy. This unusual immunophenotype seems to be associated, in this and other cases reported previously, with a more aggressive course than the classic indolent course of cutaneous T-cell lymphoma.

Antigens, Differentiation, T-Lymphocyte↗
PubMed1988

Distribution of the CD45R antigen in the maturation of lymphoid and myeloid series: the CD45R negative phenotype is a constant finding in T CD4 positive lymphoproliferative disorders.

We have compared the expression of the common leucocyte antigen (CD45) and the restricted leucocyte antigen (CD45R) on normal haematopoietic cells, cell lines, and a total number of 136 cases of myeloid and lymphoid proliferative syndromes. CD45, the conventional leucocyte antigen, presents a generalized distribution along the lymphoid and myeloid maturation pathway with the exception of some myelomas and pre-B leukaemias. In contrast, the expression of the CD45R determinant is more limited. Although it is found in the majority of the differentiation stages of B cells and monocytes, it is present only in the early stages of myeloid differentiation. On T cells it is expressed on mature thymocytes and in the majority of CD8+ lymphocytes and a subset of CD4+ cells on peripheral blood. Finally, our results also indicated that CD4+ T lymphoproliferative syndromes are derived from the CD4+ CD45R- subset (20/20 cases).

Animals↗
PubMed1988

Monocytoid B-cell lymphoma, a tumour related to the marginal zone.

Monocytoid B-lymphocytes are a B-cell subset present in subcapsular sinuses in some cases of lymphadenitis. We describe a case of lymphoma of this cell type. The tumour shows a distinctive morphology characterized by concentric strands of tumour cells around lymphoid follicles with hyperplastic germinal centres and conserved mantle zones. Electron microscopy of these cells shows short cellular processes as well as moderate development of endoplasmic reticulum. The phenotype of the tumour was monoclonal IgM-kappa, distinct from other node-based B-cell subpopulations and suggesting a possible relationship to the lymphocytes of the marginal zone present peripheral to lymphoid follicles of the spleen. Morphological features that suggest a relationship with hairy cell leukaemia are contrasted by phenotypic differences and the ultrastructural absence of ribosomic lamellar complexes.

Aged↗
PubMed1987

Persistent and generalized lymphadenopathy: a lesion of follicular dendritic cells? An immunohistologic and ultrastructural study.

An immunohistochemical and ultrastructural study of 14 cases of persistent and generalized lymphadenopathy (PGL), acquired immune deficiency syndrome (AIDS) related, revealed florid follicular hyperplasia, follicular dendritic cell (FDC) lysis, lymphoid follicle invaginations, increased presence of T8 cells in germinal center, immature sinus histiocytosis (monocytoid B-cells), and inversion of T4/T8 ratio in the paracortical area. Electron microscopic examination showed viral particles of morphologic characteristics consistent with human immunodeficiency virus (HIV) virions attached to the processes of FDC in three of the nine cases studied. Lesions of the germinal center dendritic cell network are the cardinal feature of PGL. This finding lends support to the idea of a viral aggression directed against FDC as the cause of disregulation of the B-cells.

AIDS-Related Complex↗
PubMed1986

Immature sinus histiocytosis a monocytoid B-lymphoid reaction.

The proliferation of characteristic cells in expanded sinuses and in the perivenular area of the paracortex of lymph nodes with patients with toxoplasmosis, and homosexual and drug abusers with lymphadenopathy is referred to as 'immature sinus histiocytosis' (ISH). In a study of nine cases we have shown that these cells are monocytoid B-cells with an immunological phenotype differing from that of other node-based B-cells. The function of these cells is not known.

B-Lymphocytes↗
PubMedDate not supplied

Phenotypic expression of histocompatibility antigens in human primary tumours and metastases.

HLA class I and II expression was studied on 244 (177 primary and 67 metastatic) solid human tumours of different origin. Alkaline immunophosphatase (APAAP) and immunoperoxidase were used on cryostatic sections to stain MHC antigens. Monomorphic MoAbs were used against class I heavy chain, beta 2-microglobulin, DR, DQ and DP molecules. Class I expression was homogeneous on colon, melanoma and epidermoidal primitive tumours. Loss of HLA class I antigens was more frequent on basal cell carcinomas and sarcomas and was related to tumour differentiation on larynx carcinoma. Class I expression was heterogeneous on breast, larynx and stomach primitive neoplasias. Class I negative tumours were more frequent on metastatic than on primitive melanomas. Divergence of class I between primary tumours and autologous metastases was observed on melanomas, larynx and colorectal carcinomas. Class II expression was heterogeneous on all tumours and in a large number of cases was associated with high intensity of leukocytic infiltrate. HLA-DR expression was higher than HLA-DP and HLA-DQ (DR greater than DP greater than DQ) and was related to tumour progression. Four human tumour cell lines were modulated with recombinant interferon-gamma for HLA class I and II antigens. Different HLA profiles were obtained: increased class I and II expression, increased class II or a low response. Finally, class I genes from 22 tumours were compared with autologous normal cells by Southern blot analysis: 12 tumours were class I positive and 10 negative. No clear differences in RFLP were observed that could be associated with class I rearrangement. The results are discussed in relation to the role that histocompatibility antigens may play in tumour progression and invasiveness.

Genes, MHC Class I↗
PubMedDate not supplied

Ultrastructure of 26 cases of Ki-1 lymphomas: morphoimmunologic correlation.

Twenty-six cases of high-grade lymphomas with activation markers (CD30) classified and immunophenotyped according to the Kiel classification were studied to determine their fine structural features. Transmission electron microscopy showed in 17 cases anaplastic nuclear and cytoplasmic changes identical to those observed in Hodgkin's disease, it being impossible to determine by the morphology a B, T, or null nature. Four high-grade B-centroblastic and immunoblastic cases and five T-pleomorphic cases showed nuclear changes and cytoplasmic differentiation that suggested a T or B nature. An immunogold-labeling technique showed CD30-positive particles primarily in the Golgi complex and occasionally in the cell membrane.

Antigens, Differentiation↗
PubMedDate not supplied

Lennert's lymphoma with giant multivesicular lysosomal bodies optically visible.

A case of a 43-year-old male patient with lymphoepithelioid lymphoma is discussed. During the 10-year follow-up of this patient, different biopsy specimens were obtained. Immunohistochemical studies with a complete paraffin panel determined a T-cell nature of the specimens. Electron microscopy showed a peculiar finding in the cytoplasms of the tumoral cells that correlated with optical inclusions observed in optical imprints; these imprints corresponded to lysosomic multivesicular bodies, whose significance is discussed.

Adult↗