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B S Wilkins

Publications and source records attributed to B S Wilkins.

At least 19 recordsLinked to original sources
PubMed1996

Splenic marginal zone expansion in B-cell lymphomas of gastrointestinal mucosa-associated lymphoid tissue (MALT) is reactive and does not represent homing of neoplastic lymphocytes.

It has been suggested that lymphocytes of mucosa-associated lymphoid tissue (MALT) arise from marginal zone cells and that MALT-derived lymphomas may spread to other extra-nodal sites by homing to marginal zones in different tissues. Marginal zone expansion has been observed in spleens removed during surgery for gastrointestinal MALT lymphoma, which was sufficiently extreme in some cases to suggest neoplastic involvement. To investigate this phenomenon, polymerase chain reaction (PCR) amplification of immunoglobulin heavy chain gene fragments was performed to demonstrate B-cell clonality in gastrointestinal MALT lymphomas and spleens from 11 patients. Monoclonal PCR products were obtained from 9 of the 11 gastrointestinal tumours but from none of the accompanying spleens. One additional spleen, for which the accompanying gastric lymphoma tissue was unavailable for review, yielded a monoclonal product. However, obvious lymphoma deposits were present in this specimen, in addition to marginal zone enlargement. It is concluded that splenic marginal zone expansion accompanying gastrointestinal MALT lymphoma is correctly interpreted as being reactive. Splenic involvement by MALT lymphoma is uncommon and does not show preferential colonization of the marginal zone to suggest homing of MALT-derived cells to this site.

B-Lymphocytes↗
PubMed1995

Activation and preferential expansion of rat cytotoxic (CD8) T cells in vitro and in vivo with a bispecific (anti-TCR alpha/beta x anti-CD2) F(ab')2 antibody.

We show that a bispecific F(ab')2 Ab (BsAb), which cross-links the TCR to CD2 ([anti-CD2 x anti-TCR]) and is highly mitogenic in vitro, also induces marked T cell activation and proliferation when given as a small single dose (50 to 100 micrograms) to rats. Interestingly, the proliferation appeared selective for CD8 cells, increasing this compartment more than 20 times over 72 h. This resulted in a three- to fourfold increase in spleen weight, with histologic evidence of T-zone and red pulp expansion by CD8+ blast cells. Such changes were in striking contrast to those seen after a similar amount of the parent IgG anti-TCR mAb, R73, which, while inducing a transient increase in CD25+ cells, failed to alter the lymphocyte composition. The mitogenic activity of the BsAb was totally dependent on its ability to cross-link CD2 and the TCR, hence a mixture of anti-CD2 and anti-TCR F(ab')2 fragments was without effect in vitro or in vivo. Unlike normal rat T cells or those taken from R73 IgG-treated rats, blood and splenic T cells recovered from BsAb-treated rats were highly cytotoxic against R73 hybridoma targets that express surface anti-TCR mAb and consequently trigger the lytic activity of activated CTL or a rat lymphoma line, LAMA (Thy-1+), using a second BsAb, [anti-TCR x anti-Thy-1], to retarget the CTL. This latter assay provides the basis for a future two-stage targeting strategy for cancer immunotherapy in which a mitogenic BsAb would be given to patients to activate CTL nonspecifically, and then, at an appropriate time, a second BsAb [anti-TCR x antitumor] would be given to deliver activated cells to the tumor target cells.

Animals↗
PubMed1995

Vascular networks within the stroma of human long-term bone marrow cultures.

The formation of branching and anastomosing vascular structures has been demonstrated within the stromal layers of human long-term bone marrow cultures (LTBMCs). Such organized vascular structures have not been described previously and may be of functional importance, as adherent granulocyte-predominant haemopoietic foci were more numerous in their interstices and margins than elsewhere in the stromal layers. Mature granulocytes were seen within vascular lumina in a few instances, possibly indicating an attempt to recapitulate the normal process of egress of neutrophils from bone marrow into the circulation. Immunostaining showed that the vascular structures expressed CD31, CD34, and CD105 (endoglin), which were not expressed by stromal fibroblastic cells. Collagen IV and laminin, expressed throughout the stroma, were present in increased amounts where vascular arrays were seen. In contrast, von Willebrand factor (VWF) and vascular cell adhesion molecule-1 (VCAM-1) were expressed equally by the vascular arrays and by stromal fibroblastic cells. Neither the arrays nor the general stroma expressed intercellular adhesion molecule-1 (ICAM-1), ICAM-2, ICAM-3, or endothelial leukocyte adhesion molecule-1 (ELAM-1).

Antigens, CD↗
PubMed1995

Immunohistochemical characterization of intact stromal layers in long-term cultures of human bone marrow.

We have performed an immunohistochemical study of intact adherent layers of human long-term bone marrow cultures (hLTBMC) in order to characterize the cell types present. Our panel of antibodies was selected to demonstrate various mesenchymal and haemopoietically derived cell types and to assess the presence of molecules of potential importance as adhesive ligands between haemopoietic cells and stroma. Subpopulations of fibroblasts and macrophages were identified which differed in immunophenotype. We were able to demonstrate modulation of fibroblast and extra-cellular matrix immunophenotypes between 2 and 12 weeks in culture. Stromal cells and matrix expressed a wide variety of antigens of potential importance in haemopoietic cell adhesion, but no ICAM-1, 2 or 3 could be demonstrated to correspond to the strong LFA-1 expression seen in haemopoietic precursor cells. No localization of antigen expression by stromal elements was found to account for the formation of haemopoietic foci at particular sites. However, granulocyte-predominant foci preferentially occupied the interstices and margins of structures which appeared to be vascular arrays.

Bone Marrow Cells↗
PubMed1995

Low-grade B-cell lymphomas of the splenic marginal zone: a clinicopathological and immunohistochemical study of 14 cases.

We have studied 14 cases of low-grade, splenic marginal zone, B-cell non-Hodgkin's lymphoma. The clinical presentation in all cases was with splenomegaly and, in 10 cases, circulating neoplastic lymphoid cells in the peripheral blood with involvement of bone marrow. In all cases the splenic white pulp was hyperplastic with expansion of marginal zones and varying degrees of infiltration of germinal centres by neoplastic cells. The cells were a mixture of medium sized lymphocytes with moderate amounts of cytoplasm and finely dispersed nuclear chromatin, together with occasional blast cells with small nucleoli. Satellite red pulp aggregates of tumour cells centred on small epithelioid cell clusters were seen in all cases. These appear to be a characteristic and diagnostically important feature of splenic marginal zone lymphoma. The tumour cells expressed CD20, CD45RA, bcl-2 and the antigens detected by MB2. All cases expressed IgM with light chain restriction. In addition, IgD was expressed in four cases. The follicular dendritic cell network was disrupted in those follicles which were infiltrated by tumour cells. A network of stromal myoid cells, at the periphery of the marginal zone, identified by expression of alpha-smooth muscle actin, was preserved. Alpha-smooth muscle actin positive dendritic cells were also seen within and around satellite tumour nodules in the red pulp.

Aged↗
PubMed1994

Extramedullary haemopoiesis in fetal and adult human spleen: a quantitative immunohistological study.

Haemopoietic cells were assessed in spleens from normal adults, adults with splenic extramedullary haemopoiesis due to chronic myeloproliferative disorders and fetuses of 17-21 weeks' gestation. A variety of antigens expressed by developing granulocytes and erythrocytes were demonstrated immunohistochemically. The relative proportions of early and late precursor cells of these two lineages were quantified. There was no significant haemopoiesis in normal adult spleen, while there was abundant (predominantly granulocytic) haemopoiesis in patients with chronic myeloproliferative disorders. Fetal spleens contained numerous late erythroid precursors but few early erythroid or granulocytic cells. The relative numbers of early and late haemopoietic cells in adult chronic myeloproliferative disorders and fetal spleens showed statistically significant differences. Our findings indicate that haemopoiesis in the spleens of adult patients with these disorders differs fundamentally from that occurring in fetal life. They support the view that the human spleen does not have a significant role in fetal haemopoiesis, but that it filters circulating nucleated erythroid precursors and is permissive of their terminal differentiation only. Our results also favour the view that adult splenic haemopoiesis originates by displacement of precursor cells from the bone marrow rather than by activation of stem cells which have lain dormant in the spleen since fetal life.

Adult↗
PubMed1994

Microwave antigen retrieval in immunocytochemistry: a study of 80 antibodies.

AIMS: To evaluate the effect of microwave irradiation on the staining quality of a range of commonly used primary antibodies in archival, formalin fixed, paraffin wax embedded material, with emphasis on antibodies that have previously worked successfully only on frozen tissue. METHODS: Immunocytochemistry (streptavidin-biotin complex technique) was performed on histological sections of a range of normal and pathological tissues, after varying treatment with microwave irradiation. The staining quality of each antibody was compared with that achieved without prior treatment of the sections or after enzyme predigestion. RESULTS: Microwave irradiation permitted successful immunostaining with 20 antibodies that stained only frozen tissues before. The staining characteristics of 21 antibodies that were already known to stain formalin fixed, paraffin wax embedded material were improved. Another 39 antibodies did not show enhanced staining with microwave irradiation. The method preserves tissue morphology and produces more consistent staining than that achieved by enzyme predigestion with many antibodies. Microwave irradiation may also allow some primary antibodies to be used at higher working dilutions. The citrate buffer used in this study avoids the necessity of exposure to heavy metal salts. CONCLUSIONS: Microwave antigen retrieval represents an important technical advance within immunocytochemistry that will greatly increase the range of antibodies which can be used to study formalin fixed, paraffin wax embedded tissues.

Antibodies, Monoclonal↗
PubMed1993

Haemopoietic regrowth after chemotherapy for acute leukaemia: an immunohistochemical study of bone marrow trephine biopsy specimens.

AIM: To analyse haemopoietic regrowth and residual disease in bone marrow trephine biopsy specimens after treatment for acute leukaemia, using immunohistochemical staining. METHODS: Biopsy specimens before and after treatment were studied from patients diagnosed as having acute myeloid or lymphoblastic leukaemia. Specimens after treatment encompassed periods from two to 56 weeks from the start of treatment. Routine haematoxylin and eosin and Giemsa stained sections were evaluated in association with immunostained preparations. A panel of antibodies was used, which reacts with epitopes showing restricted expression dependent on the lineage or maturation stage of cells. Results were evaluated in the light of clinical, peripheral blood, and marrow aspirate findings. RESULTS: The speed and sequence of regrowth of haemopoietic cells were more variable than expected. Immunostaining highlighted features of dysplasia after treatment and in some cases assisted detection of residual or relapsed leukaemia. Peripheral blood and aspirate cell counts reflected accurately the amount of regrowth, but not the dysplasia, seen in biopsy samples. Delayed regrowth was associated with complex individual factors. CONCLUSIONS: Morphological and immunohistochemical study of trephine biopsy specimens from patients treated for acute leukaemia provides information complementary to that obtained from peripheral blood and aspirated marrow. Variation in the timing and sequence of regrowth is highlighted. Immunostaining can aid in the detection of relapse or minimal residual leukaemia. The clinical relevance of dysplastic changes in biopsy specimens after treatment is uncertain, but such changes may persist for long periods.

Acute Disease↗
PubMed1992

A study of cell proliferation in formalin-fixed, wax-embedded bone marrow trephine biopsies using the monoclonal antibody PC10, reactive with proliferating cell nuclear antigen (PCNA).

We have investigated proliferation in bone marrow trephine biopsies from 32 patients with normal or abnormal haemopoiesis, using the monoclonal antibody PC10, which detects proliferating cell nuclear antigen (PCNA), together with immunohistochemical markers of haemopoietic cell lineage. PCNA immunostaining revealed the pattern of proliferation within individual haemopoietic lineages in normal marrow. Two unexpected observations were made: of erythroid cells, only pro-erythroblasts and occasional early normoblasts reacted, and positivity of megakaryocytes was unrelated to nuclear lobulation or CD61 expression. The pathological cases represented conditions in which haemopoiesis is increased (reactive hyperplasia, chronic granulocytic leukaemia, myeloproliferative and myelodysplastic syndromes, megaloblastic anaemia). Increases in the number, and disturbances of the spatial organization, of PCNA-expressing cells were present to a variable extent in all cases. Sheets of PCNA-positive megaloblastoid erythrocytes were frequently found in myelodysplastic and myeloproliferative tissue, associated with marked disturbances in the spatial organization of all haemopoietic lineages. Cases of megaloblastic anaemia due to vitamin B12/folate deficiency also demonstrated greatly increased erythroid PCNA expression, with positivity in some giant metamyelocytes. In addition to reflecting increased proliferation, elevated PCNA expression in some bone marrow pathologies may be due to altered kinetics of the protein induced by disturbances in growth factor production.

Autoantigens↗
PubMed1992

The expression of the EBV latent membrane protein (LMP-1) is independent of CD23 and bcl-2 in Reed-Sternberg cells in Hodgkin's disease.

A series of 33 cases of Hodgkin's disease was investigated for the presence of the EBV encoded latent gene product LMP-1 and of CD23 using immunohistochemical techniques. The expression of bcl-2 was examined in a subset of cases. LMP-1 was detected in the Reed-Sternberg cells in 15 cases. Although LMP-1 is known to upregulate CD23 and bcl-2, there was no correlation between the expression of LMP-1 and the detection of CD23 and bcl-2 in Reed-Sternberg cells.

Adolescent↗
PubMed1992

The effect of glycosylation trimming enzyme inhibitors on monoclonal antibody recognition of alpha-sialoglycoprotein epitopes.

The human erythrocyte membrane contains four sialoglycoproteins, denoted alpha, beta, gamma and delta (also known as glycophorins A, C, D and B respectively), of which alpha-sialoglycoprotein (alpha-SGP) is the most predominant species. The extracellular portion of alpha-SGP is heavily glycosylated with approximately 15 O-linked carbohydrate side-chains and a single N-linked group. We have used inhibitors of carbohydrate trimming enzymes to investigate the contribution of this single N-glycan moiety towards the recognition of a range of antibody binding sites on alpha-SGP. Two erythromyeloid cell lines, K562 and HEL, were cultured in the presence of these inhibitors and altered binding of antibodies to epitopes adjacent to the N-glycan was observed. Digoxigenin-coupled lectins were used to stain cytocentrifuge preparations and Western blots of cell lysates in order to confirm that modification of N-linked carbohydrate side-chains had been achieved. We suggest that the N-glycan side chain of alpha-SGP has a role in conferring conformational stability upon epitopes which lie in its vicinity.

1-Deoxynojirimycin↗
PubMed1992

Cell-stroma interactions in monocytopoiesis.

We have used immunohistochemistry to distinguish monocytes from early granulocyte precursors in trephine biopsies, in order to determine the distribution of monocytopoiesis within bone marrow. Developing granulocytes and monocytes have extensively overlapping immunophenotypes, but differential expression of calgranulin by monocytes and granulocytes during their maturation permitted the use of this antigen as a marker of bone marrow monocytes. In addition to morphologically normal bone marrow biopsies, in which monocyte numbers are relatively low, we studied pathological conditions in which either monocytopoiesis or granulopoiesis is selectively increased. By contrast with the highly zonal distribution of developing granulocytes, we found that monocytes were dispersed singly throughout the bone marrow. There was no evidence of preferential localisation of monocytes to particular stromal compartments. We hypothesise that developing monocytes are highly mobile within the bone marrow stroma and are relatively independent of physical stromal contacts for differentiation signals.

Bone Marrow↗
PubMed1992

Criteria for the definition of Epstein-Barr virus association in Hodgkin's disease.

There is a clear association between the Epstein-Barr virus (EBV) and Hodgkin's disease (HD). EBV is not, however, detectable within the affected tissues of all cases. The proportion of positive cases varies from 15-79% depending on the assay used to detect EBV. The techniques utilised vary not only in sensitivity but in their ability to detect viral DNA, RNA, or protein and in their ability to demonstrate the cellular localisation of the virus. Thus, the biological significance of a positive result will vary depending on the method of analysis. In the present study, four different methods of detecting EBV were compared. RNA in situ hybridization was found to be the most practical method of detecting EBV in tumour cells. Using this assay EBV was detected in the Reed-Sternberg cells of 33% and 45% of the two series of HD cases examined in this study. We believe that these cases should be considered EBV-associated.

Adolescent↗
PubMed1991

Partial placenta membranacea.

Seven pregnancies complicated by partial placenta membranacea occurring over a 2-year period are described. The condition is encountered more frequently than the total or near-total form, but is similarly associated with recurrent antepartum haemorrhage, miscarriage or preterm delivery. Diagnosis by ultrasound scan may prove difficult. Five pregnancies had histological evidence of chorioamnionitis, which may have helped to precipitate labour; three fetuses showed pulmonary inflammatory changes of at least 2 days' duration. No maternal predisposing factors could be elicited.

Chorioamnionitis↗
PubMed1989

Morphological and immunohistological study of testicular lymphomas.

We have studied normal testis, seminomas and malignant lymphomas of the testis using routine stains and a panel of antibodies directed against lymphoid and basement membrane antigens. The results show that normal testis contains, at most, a minor population of T-lymphocytes: seminomas contain mixed T- and B-cell populations with a predominance of B-lymphocytes; and most primary lymphomas are B-cell tumours of large centroblastic type. Solid testicular lymphomas presenting secondarily to acute lymphoblastic leukaemias showed intact seminiferous tubular basement membranes with predominantly interstitial lymphomatous infiltrates, whereas the tubules in primary cases were over-run by lymphoma cells and basement membranes were disrupted.

Antibodies, Monoclonal↗