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Biomedical subjects

I A Lampert

Publications and source records attributed to I A Lampert.

At least 19 recordsLinked to original sources
PubMed2005

Centrocytoid plasma cells of the germinal center.

Germinal centers within the lymph node follicles are T-cell-dependent, antigen-driven B-cell proliferations that develop from the rapid clonal expansion of a few founder cells. The end results of this B-cell expansion are memory B cells or plasma cells. Two morphologic forms of plasma cell can be recognized in the germinal center: classic plasma cells, characterized morphologically by peripherally clumped arrangement of nuclear chromatin, and cells with a nuclear morphology more resembling that of the centrocytes, which the authors have termed "centrocytoid plasma cells." In this study the authors examined the distribution and immunohistochemical characteristics of these two populations of germinal center plasma cells. The centrocytoid plasma cells were arranged in a band stretching from the junction of the dark and light zone to the periphery of the germinal centers, while the classic plasma cells were mainly present at the germinal center periphery. Both marked with CD38, CD138, and VS38c, recognized markers for plasma cells; however, EMA and CD31 were present only in the classic form of plasma cell. The proliferation marker Ki67 was present in less than 1% of the cells labeling with CD138. Others have demonstrated Ki67 in 50% of the cells labeled with Blimp-1, which is consistent with Blimp-1 appearing earlier than CD138 in ontogeny. CD10 is co-expressed with CD138 in about 10% of cells and CD45 with CD138 in about 5% of cells. Their topographic features, together with the progressive acquisition of plasma cell markers, suggest that the centrocytoid plasma cells may be the precursors of the classic plasma cells. Of note, both the forms of plasma cell were absent in follicles of follicular lymphoma, which supports the concept that in this disease, lymphocytes fail to differentiate and mature beyond the centrocyte stage.

Biomarkers↗
PubMed2003

Epstein-Barr virus gene expression in human breast cancer: protagonist or passenger?

The presence and transcriptional expression of Epstein-Barr virus (EBV)-encoded genes, oestrogen receptor (ER) status and degree of lymphocyte infiltration were evaluated in 15 mastectomy-removed breast cancer samples, mostly of ductal origin. With regard to these parameters, the tumours were heterogeneous. Viral genes, including EBNA1 - a universal EBV marker - and others, selected in part on the basis of expression in other EBV-associated carcinomas and/or presence in an epithelial cell immortalising subfragment p31 of viral DNA, were detected in up to 40% of the breast malignancies. The small viral RNAs, EBERs, were not observed. In culture, p31 EBV DNA, alone among EBV fragments, stimulated the growth of human breast-milk epithelial cells. There was no correlation between viral and ER expression and tumours were heterogeneous with regard to their invasive lymphocytes: of three studied in detail, one contained none, another had (mainly) T-lymphocyte aggregates on the tumour periphery, and a third (BC 12) was infiltrated with both T- and B-lymphocytes. BC 12 differed in several aspects from other malignancies in expressing a transcriptional activator (BZLF1) associated with overcoming virus latency, and failing to express a viral oncogene, BARF1. Arguments are given for EBV as a protagonist cocarcinogen in some breast malignancies.

Breast Neoplasms↗
PubMed1999

High expression of CD23 in the proliferation centers of chronic lymphocytic leukemia in lymph nodes and spleen.

Chronic lymphocytic leukemia (CLL) is a B-cell neoplasm composed of a heterogeneous mixture of cells, including small lymphocytes, prolymphocytes, and large transformed cells; these last cells appear to represent the proliferating compartment. CLL cells express, in addition to B cell markers, the transmembrane receptor CD23. CD23 functions as the receptor for IgE and also appears to play a role in controlling the growth and proliferation of lymphocytes. Its level of expression among the different cells in CLL has not been examined. In this study, we show that CD23 expression is much higher in the large transformed CLL cells than in the small lymphoid population. This may provide an explanation for the observed correlation between a circulating CD23 cleavage product (soluble CD23) and prognosis in CLL. In addition, we have shown that proliferation in splenic CLL occurs preferentially in the white pulp zones, even in cases in which both the white and red pulp are extensively infiltrated.

Aged↗
PubMed1996

T-cell lymphomas in v-Myb transgenic mice.

v-Myb, the transforming protein of avian myeloblastosis virus, causes acute myeloid leukemia in chickens. Similarly, truncation and rearrangement of the c-myb proto-oncogene to yield a v-Myb-like protein leads to myeloid and B cell lymphomas in chickens and mice, and may be a factor in a number of human cancers. To study the effects of deregulation of v-Myb on T cell development, we have generated lines of transgenic mice in which the v-Myb oncoprotein is expressed in a T-cell-specific fashion. Analysis of T cell development in the v-Myb transgenic mice shows that ectopic expression of v-Myb affects the ratio of helper to cytotoxic T cells, by increasing the number of CD4+ helper cells, and inhibits thymic involution, such that mature animals have elevated numbers of thymocytes and circulating mature T cells. In a significant proportion of older animals, high grade T cell lymphomas develop, demonstrating that v-Myb is oncogenic in T cells.

Animals↗
PubMed1996

Acetyl cholinesterase is expressed in the follicular dendritic cells of germinal centres: differences between normal and neoplastic follicles.

Acetyl cholinesterase (AcChE) was demonstrated by histochemistry in the follicular dendritic cells (FDCs) of the germinal centres of lymph nodes, tonsils, and bowel lymphoid tissue. Its presence in the FDCs was confirmed by double immunostaining for CD21 or DRC-1. AcChE-positive FDCs are concentrated in the inner portion of the light zone of the germinal centre, being absent from the dark zone. In the lymphoid tissue surrounding the germinal centres are AcChE-positive blood vessels; double staining shows that the AcChE is present in the pericytes surrounding the endothelium of the blood vessels. In contrast to the reactive follicle, the AcChE reactivity in FDCs of follicle centre lymphoma is absent or minimally expressed, although the dense FDC mesh is well stained with CD21 or DRC-1. This suggests that the AcChE is not constitutively expressed in FDCs but that its expression is influenced by the state and activity of the lymphoid cells in the germinal centre. The reduced level of AcChE staining can be profitably employed in the diagnosis of follicle centre lymphoma.

Acetylcholinesterase↗
PubMed1993

Protection of germinal centres from complement attack: decay-accelerating factor (DAF) is a constitutive protein on follicular dendritic cells. A study in reactive and neoplastic follicles.

The development of B-cell memory is linked to the presence of germinal centres. This process is dependent on the presence of antigen, usually in the form of immune complexes with antibody, on the surface of the follicular dendritic cells (FDCs) that form a network in the germinal centre. The presence of immune complexes poses a constant danger of activating complement. Decay accelerating factor (DAF, CD55) and the membrane attack complex (MAC) inhibitor (CD59) are two cell proteins whose sole function is to protect cells from the action of complement, the former affecting the earlier components of the complement cascade, and the latter the terminal ones; both are bound to the cell surface via a glycosylphosphatidylinositol link. DAF but not CD59 could be demonstrated on FDCs. DAF is also present on the FDCs in follicular lymphomas despite the absence of complement (C3) in neoplastic follicles. This indicates that DAF is constitutive to FDCs but does not preclude the possibility that its expression is increased when immune complexes are deposited.

Antigens, CD↗
PubMed1991

Leukaemia as a manifestation of large cell lymphoma.

A leukaemic phase is uncommon in large cell lymphoma, particularly at presentation of the disease, and very few cases have been reported since immunological markers became available. We have studied 24 cases presenting over a period of 15 years. 16 were B-lineage and eight T-lineage. In five patients the large cell lymphoma represented a transformation of a preceding low grade, small cell lymphoproliferative disease. Three other patients with T-lineage large cell lymphoma presented with skin infiltration (two cases) or lymphoma-associated nephrotic syndrome (one case) 3-9 months before leukaemia occurred. The other 16 patients (12 B-lineage and four T-lineage) presented with de novo large cell leukaemia/lymphoma. With the exception of skin infiltration, clinical features did not differ between T and B-lineage cases. Prognosis was generally poor although a minority of patients lived 1-2 years. Median survival was 7 months. In the B-cell lymphomas immunological markers were those expected but among the T-cell cases there were many unusual immunophenotypes with frequent failure to express markers which are usually positive in peripheral T cells. Without the availability of immunological markers diagnosis would have been difficult, with acute myeloid leukaemia being the most important differential diagnosis. T-lineage and B-lineage cases could not be distinguished on cytological features. In the majority of cases the cells were very pleomorphic with nuclear lobulation, prominent nucleoli and marked cytoplasmic basophilia being commonly observed. Marked nuclear lobulation was not confined to T-lineage cases but was seen also in seven of 12 cases of de novo B-lineage leukaemia/lymphoma; it was readily apparent in histological sections and on ultrastructural examination.

Adolescent↗
PubMed1991

Sweat gland abnormalities in lichenoid dermatosis.

Lichenoid dermatosis is a pattern description of a variety of cutaneous lesions which primarily affect the dermoepidermal junction. Involvement of skin appendages has been restricted to hair follicles in lichen planopilaris and discoid lupus erythematosus. Sweat gland involvement has not been described in the four common members of this group, namely, lichen planus, discoid lupus erythematosus, fixed drug eruptions and erythema multiforme, although structural abnormalities have been reported in graft-versus-host disease. In a detailed morphological study of 59 cases, including lichen planus (12), discoid lupus erythematosus (18), fixed drug eruption (14) and erythema multiforme (15), 78% (47/59) showed sweat, gland abnormalities. The abnormalities included vacuolation of cell cytoplasm, with and without lymphocytic infiltration, apoptosis of basal cells and basal cell hyperplasia of the excretory ducts which predominantly affected the portion of the duct adjoining the acrosyringium. The portion of the duct close to the secretory gland was only involved in continuity and the secretory glands were unaffected. These abnormalities of the sweat gland mostly constitute primary involvement by the disease process in contrast to structural abnormalities secondary to fibrosis.

Drug Eruptions↗
PubMed1991

The sweat gland in cutaneous vasculitis.

Cutaneous vasculitis commonly presents as palpable purpura, and the late stages may become nodular, bullous, infarcted and ulcerated. Involvement of sweat glands in vasculitic lesions has not been previously described. In a detailed study of 48 cases of non-infarcted cutaneous vasculitis, 18 (36%) revealed morphologically abnormal sweat glands. Basal cell degeneration, necrosis, regeneration and basal cell hyperplasia were found in the excretory ducts. Necrosis of the secretory gland was seen either as apoptosis involving the clear cells or as a whole gland necrosis involving both cell types. This unusual feature has only been described in association with coma, commonly due to barbiturate and carbon monoxide poisoning. Its presence in non-infarcted vasculitis adds support to the hypoxia/ischaemia hypothesis. The functional impact of such lesions in widespread cutaneous vasculitides requires further study.

Adolescent↗
PubMed1990

A variant form of hairy cell leukemia resistant to alpha-interferon: clinical and phenotypic characteristics of 17 patients.

We describe the clinical and laboratory features of 17 adult patients with a variant form of hairy cell leukemia (HCL-V) studied over the last 7 years. The main findings were: splenomegaly, moderate anemia, thrombocytopenia, and a raised white blood cell count (median 116 x 10(9)/L; range 15 to 482). The circulating lymphoid cells had abundant villous cytoplasm and a round, occasionally bilobed nucleus, with a prominent nucleolus. Monocytopenia, a feature of typical HCL, was not seen; neither was tartrate-resistant acid phosphatase demonstrated in eight cases tested. HCL-V cells had a mature B-cell phenotype: CD19+, CD20+, CD22+, FMC7+, CD11c+, CD10-, CD5-, with light chain isotope restriction in 15 cases. In contrast to typical hairy cells, HCL-V cells were negative with the monoclonal antibodies anti-HC2 and anti-TAC (CD25). Immunoglobulin (Ig) was not detected in two cases and IgG was expressed in the cell membrane of 73% of cases. Bone marrow histology was different from HCL, showing interstitial infiltration by cells clumped together and a moderate amount of reticulin, but the spleen showed the typical red pulp expansion of HCL. HCL-V patients did not respond to splenectomy (5 of 7) or alpha-interferon (7 of 7); 2 of 3 patients had a partial response to 2'deoxycoformycin. The clinical course was benign with 15 patients alive with a median survival greater than 4 years. We confirm that HCL-V is a distinct clinico-pathologic entity with intermediate features between HCL and B-prolymphocytic leukemia.

Aged↗
PubMed1990

The sweat gland in graft versus host disease.

Sweat gland abnormalities occur much more frequently than hitherto described in cutaneous graft versus host disease (GVHD). Two patterns of abnormalities were identified in 80 per cent of cases of acute GVHD: a cytopathic pattern consisting of a combination of basal vacuolopathy with or without lymphocytic infiltration and basal cell degeneration, and a proliferative pattern consisting of basal cell hyperplasia. In chronic GVHD, complete sweat gland destruction with fibrosis was commonly observed. Squamous metaplasia and dilation of the sweat glands were less frequently identified. Ki67 immunostaining confirmed proliferative activity in the basal cells of the distal duct. HLA-DR antigens were expressed on the basal cells of the duct and secretory glands in acute GVHD but not in normal skin. Langerhans cells were absent in both normal and abnormal sweat glands. The role of HLA-DR or Langerhans cells in the initiation of GVHD is questioned in the light of the new data and the primary involvement of proliferating cells is confirmed.

Acute Disease↗
PubMed1990

Subcutaneous sarcoidosis mimicking carcinoma of the breast.

A 65 year old woman presented with bilateral breast lumps. Clinical examination suggested a diagnosis of mammary carcinoma, but a histological diagnosis of sarcoidosis was made. Subsequent investigations revealed evidence of pulmonary sarcoidosis.

Aged↗
PubMed1989

Cyclosporin A prevents the in vivo development of murine prothymocytes from uncommitted (Thy-1-) precursor cells.

Cyclosporin A (CsA) is known to cause atrophy of the thymic medulla in normal mice. We show that medullary regeneration in lethally irradiated animals reconstituted with syngeneic marrow is also inhibited. For such animals, thymic cortical development is apparently normal. However, if the marrow is depleted of either Thy-1+ or Lyt-1+ cells, thymic regeneration is severely inhibited by CsA. This is not a permanent process, since thymic regeneration proceeds normally if the drug is withdrawn. CsA is only effective at preventing thymic regeneration if it is given at the time of grafting; after a delay of 3 days it is ineffective. We conclude that CsA inhibits the development of prothymocytes (pre-T cells) from common stem cells in the marrow. The significance of these findings with reference to T-cell ontogeny and clinical bone marrow (BM) transplantation is discussed.

Animals↗