Carcinosarcoma of the liver with mesenchymal differentiation: a case report

Carcinosarcoma of the liver with mesenchymal differentiation are very rare in adult patients. A case is reported with an exhaustive pathologic examination and review of the literature. A 61-year old man presented with general fatigue and dull abdominal pain. Two liver masses were diagnosed and resected by a right hepatectomy. Specimen pathology revealed that the tumor and lymph node consisted of two cancerous components. One carcinomatous component corresponding to a hepatocellular carcinoma and a sarcomatous component characterized by a diffuse proliferation of spindle shaped cells with chondrosarcomatous and osteosarcomatous changes. Patient died 9 months later of a diffusion of the tumor. For the first time, to our knowledge, a mesenchymal differentiation is demonstrated in liver carcinosarcoma.

Nonhereditary colonic angiodysplasias: histomorphometric approach to their pathogenesis

The pathogenesis of colonic angiodysplasias, more accurately termed vascular ectasias (VE) has not been definitely established. The aim of this study was to assess that the VE of noncirrhotic patients are not associated with diffuse abnormalities of the colonic mucosal microvasculature unlike the VE of cirrhotic patients. Three groups of nine consecutive patients were studied: group I, control patients with an irritable bowel syndrome; group II, noncirrhotic patients with VE; and group III, alcoholic cirrhotics with VE. A histomorphometric analysis of normal-appearing colonic mucosa was achieved from biopsies taken at six predetermined sites. Noncirrhotics with VE had a significantly lower mean number of mucosal capillaries and a significantly lower mean cross-sectional area of mucosal capillaries than alcoholic cirrhotics with VE. Alcoholic cirrhotics with VE had a significant increase of all the vascular parameters compared to the control group. There was no difference between the control patients and the noncirrhotic patients with VE. These results suggest that the VE of noncirrhotic and cirrhotic patients are entities of distinct pathogenesis.

Intratumoral activation of CD8-positive cytotoxic lymphocytes in acquired immunodeficiency syndrome lymphomas

The incidence of lymphomas is unusually high in human immunodeficiency virus (HIV)-infected patients. Because cytotoxic T lymphocytes (CTL) represent a major mechanism of the antitumoral immune response in immunocompetent individuals, we asked whether intratumoral activation of CTL was impaired in acquired immune deficiency syndrome (AIDS) lymphomas. Immunohistochemical experiments showed that in AIDS lymphomas intratumoral CD8-positive T lymphocytes accumulated and expressed the TIA-1 antigen, a marker of cytotoxic cells. Flow cytometry studies and in situ hybridization of lymphomatous tissue confirmed the differentiation of CD8-positive cells in cytotoxic cells and their activation, as assessed by their expression of CD38 and human leukocyte antigen (HLA) DR markers as well as the perforin and granzyme B genes, which code for two molecules involved in target cell killing. On average, perforin-producing cells were as numerous in AIDS lymphomas (5,647 +/- 2,655 cells/cm2) as in lymphomas from immunocompetent individuals (3,294 +/- 1,544 cells/cm2). The density of activated CD8-positive cells in the 22 AIDS lymphomas tested was not correlated with peripheral CD4-positive cell counts. These results suggest that in AIDS lymphomas the steps of differentiation and activation of cytotoxic CD8-positive cells are not altered by immune deficiency and that they can take place through pathways relatively independent of CD4-positive T lymphocytes. Thus, other mechanisms of immune deficiency should account for the increased frequency of lymphomas in patients with AIDS.

Increased expression of perforin and granzyme B genes in patients with metastatic melanoma treated with recombinant interleukin-2

The frequency of peripheral blood cells expressing the perforin gene or the granzyme B gene was evaluated by in situ hybridization in nine patients suffering from metastatic melanoma and treated with recombinant interleukin-2 (rIL-2). A spontaneous expression of both genes was detected in five to seven patients. rIL-2 administration increased the frequency of positive cells in all patients (P < 0.03 for each gene), the highest frequency being reached in the patients who already expressed these genes prior to rIL-2 treatment (P < 0.02). Expressions of the granzyme B gene and of the perforin gene were strongly correlated before IL-2 treatment and they were similarly affected by rIL-2 administration. In contrast, their modification under treatment did not correlate with that of CD56+ cell counts, of natural killer activity and of sCD8 release. This indicates that perforin and granzyme B gene expressions are markers of cytotoxic cell activation independent of those previously described, and that they should be further evaluated in patients with malignancies to delineate their potential value in predicting clinical outcome.

Production of the RANTES chemokine in delayed-type hypersensitivity reactions: involvement of macrophages and endothelial cells

To understand the selective accumulation of memory T helper lymphocytes and of macrophages in delayed-type hypersensitivity (DTH) granulomas, we studied the in situ production of RANTES, a chemokine initially characterized on the basis of its in vitro chemotactic properties for each of these cell populations. RANTES gene expression was studied by in situ hybridization in 15 human lymph nodes presenting typical DTH lesions related to either sarcoidosis or tuberculosis. A positive signal was detected in all cases. Labeling was specific for the DTH lesions, as very few if any positive cells were detected in the normal residual lymphoid tissue surrounding them or in reactive lymph nodes involved in a B lymphocyte response. RANTES gene expression was associated with the production of the protein, which was detected by immunochemistry in DTH lymph nodes. The morphological characteristics and distribution of positive cells in in situ hybridization and immunochemical experiments indicated that macrophages and endothelial cells, two cell populations not previously reported to produce RANTES, contributed to its production in DTH reactions. The ability of macrophages and endothelial cells to produce RANTES was confirmed by in vitro studies with alveolar macrophages and umbilical vein endothelial cells. In view of the chemotactic properties of RANTES for a limited range of cell populations, these results suggest that RANTES production in DTH granulomas may play a role in the selective accumulation of macrophages and memory T helper lymphocytes characterizing this type of cell-mediated immune reaction, and that macrophages and endothelial cells are involved in this production.

In situ detection of activated cytotoxic cells in follicular lymphomas

The presence of cytotoxic cells and their activation status were analyzed in tissue sections of 26 follicular lymphomas. To this end, expression of the perforin and granzyme B genes was studied by in situ hybridization experiments, and expression of the TIA-1 antigen was analyzed by immunohistochemistry. Cells expressing the granzyme B gene and the perforin gene were detected in all cases. Their density was, however, highly heterogeneous from case to case, ranging from 160 to 7,040 positive cells/cm2 of tissue sections. TIA-1-positive cells were also evidenced in the 10 follicular lymphomas tested. Virtually all cytotoxic cells were located in interfollicular areas. Double labeling immunochemical experiments showed that most cytotoxic cells belonged to the CD8+ T lymphocyte population, although few CD4+ T lymphocytes and CD56+ natural killer cells also expressed the TIA-1 antigen. These findings show that development of a malignant B lymphocyte proliferation is associated with a host-derived immune response involving intratumoral cytotoxic T lymphocytes. Further studies comparing the density of such cells with the final outcome are required to determine whether the intensity of this immune response has a prognostic value.

Intratumoral production of IL-6 in B cell chronic lymphocytic leukemia and B lymphomas

Interleukin-6 is a major B lymphocyte growth factor, and may play a role in the proliferation of malignant B lymphocytes. In order to provide arguments supporting such a role, the intratumoral production of IL-6 was studied by in situ hybridization and immunohistochemistry in 53 neoplastic tissues from B cell chronic lymphocytic leukemia or B lymphomas. IL-6-producing cells were detected in all samples but 5. However, the number of IL-6 producing cells was variable amongst the different cases. Increased density of IL-6-producing cells was highly dependent on the presence of malignant immunoblasts within the neoplastic clone. IL-6 was produced in a paracrine way, macrophages and endothelial cells being the main producers of the cytokine while malignant immunoblasts expressed the IL-6 receptor. Taken together, these results suggest that IL-6 may indeed act as a growth factor for malignant cells in some B lymphoproliferations and that this paracrine loop could be the target of new therapeutic approaches.

Interleukin-6 gene expression in Castleman's disease

Defined by histological criteria, Castleman's disease (CD) is a clinically and histologically heterogeneous syndrome. The functional status of immune cells in affected tissues may vary between the different forms of the disease. To address this question, the expression of cytokine genes in eight CD lymph nodes was analyzed by in situ hybridization. Two lymph nodes were taken from patients with a localized form of the disease associated with systemic manifestations, two from patients with a localized form without systemic symptoms, and four from patients with a multicentric form. Five lymph nodes exhibiting a benign follicular hyperplasia were used as controls. The interleukin-6 (IL-6) gene was expressed at a very high level in two cases: the two localized forms of CD associated with systemic manifestations. IL-6 gene overexpression occurred inside follicles of these lymph nodes. The morphology of follicular cells hybridizing with the IL-6 probe or labeled with an anti-IL-6 monoclonal antibody suggested that follicular dendritic cells expressed the IL-6 gene. In contrast, no IL-6 gene expression was detected inside follicles of the six other CD lymph nodes or of the five control lymph nodes. In interfollicular areas, IL-6 gene-expressing cells were detected in all lymph nodes by both in situ hybridization and immunohistochemistry. In CD lymph nodes, positive cells were located outside sinuses, in close contact with blood vessels and plasma cells. This distribution was clearly different from that observed in control lymph nodes, in which IL-6 gene-expressing cells were present inside sinuses. A similar difference between CD and control lymph nodes was observed for the distribution of IL-1 beta and IL-1 alpha gene-expressing cells in interfollicular areas. The morphology of interfollicular IL-6-producing cells was heterogeneous, consistent with that of macrophages, interdigitating cells, lymphocytes, and endothelial cells, and different from that of plasma cells. Taken together these results show that CD is consistently associated with a particular pattern of IL-6 gene expression in interfollicular areas whereas elevated IL-6 gene expression inside follicles only occurs in the localized form of the disease associated with systemic manifestations. The variable pattern of IL-6 gene expression as well as the clinical and histologic heterogeneity of CD indicate that different immune mechanisms may be involved in the different forms of this disease.

In vivo expression of IL-1 beta and IL-6 genes during viral infections in human

Macrophage infiltration is a constant feature of human virus-infected tissues. However, the in situ functional status of these cells remains undetermined. In order to document an activation of macrophages in virus-infected tissues, the expression of IL-1 beta and IL-6 genes was analyzed using in situ hybridization. Several tissues were studied, as well as infections induced by different viruses: lymph nodes infected by HIV-1 (9 cases) or EBV (one case), lungs infected by CMV (5 cases) or adenovirus (1 case), livers infected by HBV, either chronically (2 cases) or acutely (7 cases presenting a fulminant hepatitis). With the exception of fulminant HBV hepatitis, IL-1 beta and IL-6 genes were expressed in all cases. IL-1 beta and IL-6 genes were usually coordinately regulated, as cells containing IL-1 beta or IL-6 mRNA were present in identical amounts and displayed a similar distribution. Analysis of the location and the morphology of monokine gene-expressing cells indicated that both small macrophages and endothelial cells expressed IL-1 beta and IL-6 genes. However, neither tingible body macrophages present in lymph node follicles nor Kupffer cells expressed these genes at a detectable level. Infected cells themselves were also negative for monokine gene expression. These findings indicate that expression of IL-1 beta and IL-6 genes by reactive cells may play a role in viral spreading limitation as well as virus-induced tissue damage.