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.

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.

The loss of Ia+ Langerhans' cells during graft-versus-host disease in rats.

The effects of graft-versus-host-disease (GVHD) on different tissues and cells were studied. High and low lymphocyte doses were employed for the induction of GVHD, and the results were compared. It was shown that ear skin was more susceptible to attack than abdominal skin. It is speculated that this could be due to the different vascular networks in the two areas. Weight loss, skin erythema, splenomegaly, histology, and Langerhans' cell density were used to assess GVHD. The Langerhans' cell density was assessed using the Ia antigen cell marker. It is shown that Langerhans' cell density is a sensitive index for confirming GVHD. Weight loss is the least sensitive indicator. The features of GVHD occurred earlier and were more severe in animals receiving the higher dose of lymphocytes, with Ia antigen appearing on the keratinocytes in the later stages of the disease. We conclude that Langerhans' cells are sensitive to the effects of GVHD and that they can provide a diagnostically useful indicator of the disease.

Effect of immunization with Escherichia coli J5 on graft-versus-host disease induced by minor histocompatibility antigens in mice.

We have used a cell-wall-deficient mutant of Escherichia coli (E coli J5) to study the effect of active and passive immunization against bacterial endotoxin (ET) in a murine model of acute graft-versus-host disease (GVHD) induced by minor histocompatibility antigens. C57BL/B6 (H-2b) mice were irradiated and grafted with 1 X 10(7) anti-Thy-1.2 and complement-treated bone marrow cells and 5 X 10(7) spleen cells from LP/J (H-2b) donors. Groups of mice were immunized against J5--either actively immunized with killed J5 cells or pure J5 lipopolysaccharide or passively immunized with rabbit anti-J5 antiserum (R alpha J5). Controls included irradiation controls, negative controls (conventional mice grafted with depleted bone marrow only), positive controls (conventional mice grafted with bone marrow and spleen cells), and mice passively immunized with normal rabbit serum (NRS). Positive control mice developed GVHD and all died by day +77. Active immunization partially protected against the rapid weight loss due to GVHD (P less than 0.05) but mice had an earlier onset of GVHD (P less than 0.05) and a shortened survival after onset (P less than 0.05). Median survival time (MST) and overall survival were unchanged. Passive immunization with R alpha J5 delayed death (P less than 0.01), increased MST (P = 0.01), increased overall survival (P less than 0.01), and protected against weight loss (P = 0.01). NRS had no beneficial effect.

Influence of endotoxin on graft-versus-host disease after bone marrow transplantation across major histocompatibility barriers in mice.

Much clinical and experimental data suggest that infection and graft-versus-host disease (GVHD) are intimately associated, and that bacterial endotoxin (ET), a potent immunostimulant, influences the severity of GVHD. We have used a cell-wall-deficient mutant of Escherichia coli (E coli J5) to study the effect of active and passive immunization against ET in a murine model of GVHD induced by major histocompatibility antigens. CBA/Ca (H-2k) mice were irradiated and grafted with 1 X 10(7) bone marrow cells from C57BL/B6 (H-2b) donors. Groups of mice were immunized against J5: either actively immunized with killed J5 cells or pure J5 lipopolysaccharide, or passively immunized with rabbit anti-J5 antiserum (R alpha J5). Controls included irradiation controls, negative controls (syngeneic graft), positive controls (conventional mice receiving allogeneic graft), mice immunized with normal rabbit serum, Freund's adjuvant (FA), or human serum albumin (HSA) in FA. Active immunization with J5 exacerbated the effects of GVHD as indicated by increased weight loss (P = 0.002) and earlier death (P = 0.043). In contrast, immunization with HSA protected against weight loss (P = 0.028), and improved survival (P = 0.008). Passive immunization with J5 had no effect. These observations support the hypothesis that ET influences the pathogenesis of GVHD, and provide a useful model for studying the effects of ET in a well-defined immunological system.

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.

Prostatic adenocarcinoma evolving into carcinoid: selective effect of hormonal treatment?

Two patients, aged 72 and 65 years, each underwent two prostatic resections spaced four and two years apart, respectively. In both cases the earlier procedure showed widespread adenocarcinoma with only occasional endocrine cells, while tissue from the later operations showed prostatic carcinoids. It is suggested that the conventional adenocarcinomas were sensitive to hormonal manipulations used in treatment, but that the originally sparse carcinoid components were resistant to this form of treatment and hence became the predominant tumours. These findings imply that endocrine differentiation in prostatic carcinoma leads to lack of sex steroid sensitivity.

Intermediate filaments in smooth muscle tumours.

Antisera to the intermediate filaments vimentin and desmin react with fixed paraffin embedded tissue. Benign uterine myomas contain both classes of filaments. Gastrointestinal "smooth muscle tumours" however often lack desmin even when they appear histologically benign. In the sarcomas examined vimentin was the only class of intermediate filament present. The diagnostic and histogenetic implications of these findings are discussed.

Splenic B cell lymphoma with circulating villous lymphocytes: differential diagnosis of B cell leukaemias with large spleens.

The clinical, haematological, morphological and histological features of a series of 22 patients presenting with splenic lymphoma with circulating villous lymphocytes were assessed and compared with those of patients with other forms of chronic B cell leukaemia in an attempt to differentiate this condition from hairy cell leukaemia, prolymphocytic leukaemia, and chronic lymphocytic leukaemia, with which this condition has many features in common. The disease was twice as common in men than in women, with a mean (SD) age at diagnosis of 72 (9) years, and the most consistent presenting feature was massive enlargement of the spleen, which showed white and red pulp disease with a plasmacytic component. Small monoclonal bands were found in 60% of cases.

Morphology and immunology of circulating cells in leukaemic phase of follicular lymphoma.

Ten patients with follicular lymphoma presented with a high white cell count (45-220 x 10(9)/l) which resembled chronic lymphocytic leukaemia (CCL): all had pronounced splenomegaly and, except one, generalised lymphadenopathy. The blood lymphocytes were small with scanty cytoplasm, densely condensed nuclear chromatin, and deep clefts originating in sharp angles from the nuclear surface. CLL cells are larger, have more cytoplasm, a different pattern of chromatin condensation, and may have shallow nuclear indentations or foldings rather than clefts. The circulating follicular lymphoma cells had moderate to strong membrane immunoglobulins (SmIg), low mouse (M)-rosettes, strong reactivity with the monoclonal antibody FMC7, and occasional expression of the CD5-antigen; at least one third of cells in each case were positive with anti-cALLa (J5,CD10). Half the cases were referred as B-CLL but none had the typical B-CLL immunophenotype: weak SmIg, M-rosettes of greater than 50%, CD5 positive, FMC7 and J5 negative. The diagnosis of follicular lymphoma was confirmed by lymph node biopsy in seven of the 10 cases. The overall response to treatment was poor and five patients died within three years of diagnosis. This aggressive form of follicular lymphoma needs to be distinguished from B-CLL as different management is required.

Apoptosis is a Common Histopathological Finding in Myelodysplasia: the Correlate of Ineffective Haematopoiesis.

Twenty-three bone marrow biopsies from patients with myelodysplastic syndromes (MDS) with typical histological features were studied, and evidence of apoptosis of erythroid and immature myeloid precursors was seen by light microscopy in each case. This was quantified and found to be significantly greater than that seen in ten normal bone marrow biopsies (p < 0.01). There was no difference in the degree of apoptosis seen in the various sub-groups of MDS proposed by the French-American-British (FAB) co-operative group. These results show apoptosis of haemopoietic precursors to be a characteristic histological finding in MDS, representing intramedullary death of these cells, a factor that may play a role in the pathogenesis of the cytopenias seen in this condition.

The Splenic White Pulp in Chronic Lymphocytic Leukaemia: A Microenvironment Associated with CR2 (CD21) Expression, Cell Transformation and Proliferation.

Splenectomy specimens from 8 cases of chronic lymphocytic leukaemia (CLL) were examined. The infiltrate in the red pulp consisted predominantly of small lymphocytes. In contrast the predominant cells in the white pulp were pro-lymphocytes and para-immunoblasts. The Ki67 marker, which identifies cells in growth phase, was also concentrated among the transformed cells in the white pulp. Staining with monoclonal antibodies for CD21, which identifies the CR2 receptor, showed that the cells in the white pulp were strongly positive in contrast to those in the red pulp which were weak or negative. These findings suggest that factors present in the white pulp promote transformation and proliferation of CLL cells.

The significance of tumour cell immunophenotype in myeloma and its impact on clinical outcome.

BACKGROUND AND AIMS: Antigen expression of multiple myeloma (MM) cells is heterogeneous. We have investigated the clinical impact of expression of some of the commonly used immunohistochemical markers in the diagnostic work-up of bone marrow trephine biopsy (BMTB) samples in MM. PATIENTS AND METHODS: BMTB samples from 107 MM patients who had received an autologous stem cell transplant (ASCT) following chemotherapy were evaluated. In 75 cases, the immunophenotype had been evaluated on two or more occasions on further follow-up. RESULTS: In the cases evaluated, 32%, 79%, 73%, 39% and 60% of cases had been scored positive for CD20, CD79a, CD56, cyclin D1 and epithelial membrane antigen (EMA) respectively. Absence of CD79a was predictive of poor overall survival (OS) from the time of transplant (p = 0.029) and poor event-free survival (EFS) from the time of transplant (p = 0.003). Absence of EMA (p = 0.02) was predictive of poor EFS from the time of diagnosis. Presence of CD56 was predictive of poor EFS from the time of diagnosis (p = 0.026). On multivariate analysis, only CD79a expression (OS and EFS from the time of transplant) and EMA expression (EFS from the time of diagnosis) maintained their significance. 13 of 75 patients showed an immunophenotypic drift during the disease course. Loss of CD20 (four cases) during the disease course in cases that were previously scored positive correlated with significant worsening both, of OS (p = 0.02) and EFS (p = 0.009) from the time of diagnosis. CONCLUSION: Immunophenotype impacts on clinical outcome in MM.

Expression of HLA-DR (Ia like) antigen on epidermal keratinocytes in human dermatoses.

Ia antigen (HLA-DR in man) has been demonstrated in keratinocytes in graft versus host disease. This study investigates the occurrence of HLA-DR in keratinocytes in the following dermatoses: eczematous dermatitis, discoid lupus erythematosus, with immunoglobulin and non-exposed skin from cases of systemic lupus erythematosus with immunoglobulin deposits, lichen planus, lichen simplex, bullous pemphigoid, pemphigus vulgaris, 'toxic erthema', tuberculid and chillblain. Keratinocyte staining was found in a variety of conditions. The unifying features of the instances of its occurrence was lymphoid infiltration and usually some focal evidence of keratinocyte damage. Thus in eczema the staining was mid-epidermal, while in discoid lupus erythematosus and lichen planus it was basal. HLA-DR staining was absent in bullous pemphigoid and pemphigus vulgaris, which is consistent with the hypothesis that in these conditions the damage is mediated by autoantibodies and complement in the absence of cellular immune attack.

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.

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.