[The morphologic variants of KSHV/HHV 8-associated lymphoproliferations]

KSHV/HHV 8 infection is associated with primary effusion lymphoma, multicentric Castleman disease (MCD) and MCD-associated plasmablastic lymphoma. We report the case of an HIV-infected male with Kaposi sarcoma, MCD in the lymph node and development of a KSHV/HHV 8-associated plasmablastic lymphoma in the liver. Immunohistochemistry revealed an HHV 8 infection of plasmablasts showing cytoplasmic IgM/lambda expression. To the best of our knowledge, liver infiltration by a MCD-associated HHV 8 positive plasmablastic lymphoma has not been documented previously. The differential diagnosis is discussed.

De novo expression of the Muc2 gene in pancreas carcinoma cells is triggered by promoter demethylation

It has been established that mucin-producing variants of different subtypes of pancreatic carcinomas, including the intraductal papillary and ductal mucinous tumors, have usually a more favorable prognosis. Intraductal papillary and ductal mucinous tumors have also been shown to ectopically express the intestinal mucin gene MUC2. The mechanism of the de novo expression of this gene in tumors may have potential implications for the modulation of its behavior. We studied, therefore, the mechanism of the de novo expression of MUC2 in pancreas carcinoma cells in vitro. The MUC2 gene promoter is methylated in the nonexpressing pancreatic cell line PANC-1 and is not methylated in the expressing cell line BxPC-3. The promoter is silenced by methylation as shown by reporter expression assays. De novo expression of MUC2 in PANC-1 cells is triggered by treating the cells with a pharmacological inhibitor of DNA methylation (5-aza-2'-deoxycytidine). There was no decrease or loss of expression of the methyltransferase DNMT1 in the MUC2-producing cells. These data show that the de novo expression of the MUC2 gene in pancreas carcinoma cells is associated with promoter demethylation. They warrant further investigations on the relationship between MUC2 promoter demethylation in pancreatic cancer and the prognosis of carcinoma patients.

Frequency of clonal intraepithelial T lymphocyte proliferations in enteropathy-type intestinal T cell lymphoma, coeliac disease, and refractory sprue

BACKGROUND

Clonal T cell receptor (TCR) gene rearrangements and loss of T cell antigens such as CD8 and TCR-beta in intraepithelial lymphocytes (IELs) may indicate the development of an enteropathy-type intestinal T cell lymphoma (EITCL) in patients with refractory sprue.

AIMS

To define the diagnostic value of these markers in duodenal biopsies from patients with villous atrophy as a result of various underlying disorders.

PATIENTS AND METHODS

Duodenal biopsies from eight patients with coeliac disease and five patients with villous atrophy caused by defined disorders were compared with three patients with refractory sprue evolving into overt EITCL, two patients with ulcerative jejunitis, and with eight patients with overt EITCL, for expression of CD3, CD4, CD8, and TCR-beta in IELs using immunohistochemistry and for clonal TCR-gamma gene rearrangements using polymerase chain reaction. In addition, biopsies from six consecutive patients with refractory sprue of uncertain cause were examined.

RESULTS

Clonal TCR-gamma gene rearrangements were found in all resected tumours of patients with EITCL, in 3/8 duodenal biopsies of patients with EITCL, in 2/2 patients with ulcerative jejunitis, in 2/3 patients with refractory sprue evolving into overt EITCL, and in 1/6 patients with refractory sprue. No rearrangements were found in biopsies from patients with refractory sprue caused by defined disorders or those with coeliac disease. Clonality in duodenal biopsies was associated with an abnormal phenotype of IELs in all cases and in all but one case in patients with evidence of underlying coeliac disease. Specificity for detection of an EITCL using immunohistology was 77% for CD8 and for TCR-beta staining, and 100% for detection of a clonal TCR-gamma gene rearrangement. Sensitivity was 62% for staining with CD8 and clonality investigation, while sensitivity reached 100% for TCR-beta staining in all investigated patients with EITCL.

CONCLUSIONS

Clonal proliferations of phenotypically abnormal IELs in refractory sprue represent an early manifestation of EITCL, for which the term "sprue-like intestinal T cell lymphoma" is proposed. This constellation is also found in duodenal biopsies from patients with an overt EITCL and is not related to other sprue syndromes, resulting in a high specificity for detection of an EITCL or refractory sprue evolving into EITCL. Overt EITCL may develop directly from coeliac disease without a precursor lesion (refractory sprue with clonal IELs) being demonstrable in duodenal biopsies or via a "sprue-like intestinal T cell lymphoma". This latter entity is a complication of coeliac disease.

Extranodal mantle cell lymphoma mimicking marginal zone cell lymphoma

AIM

We report a case of mantle cell lymphoma masquerading as a marginal zone cell lymphoma.

METHODS AND RESULTS

In the initial manifestation in the palatine tonsils, the neoplastic cells were found to grow exclusively within the marginal zones of secondary follicles which showed a preserved mantle zone. The few immunostains performed showed a B-cell phenotype including an immunoglobulin light chain restriction. The extranodal manifestation, the growth pattern, and the immunophenotype led to the diagnosis of an extranodal marginal zone B-cell non-Hodgkin's lymphoma (NHL). The specimen from the relapse occurring 8 months later exhibited diffuse monomorphous cells co-expressing B-cell antigens and CD5, CD43 and cyclin D1, leading to the diagnosis of mantle cell lymphoma. Re-investigation of the initial biopsy revealed that the neoplastic cells within the marginal zones had a mantle cell lymphoma immunophenotype expressing cyclin D1, the immunoglobulin heavy chains IgD and IgM and partly CD5. Both lesions harboured identical clonal immunoglobulin gene rearrangements proving that they represented different manifestations of the same lymphoma.

CONCLUSION

This case emphasizes the importance of broad immunohistological investigation of B-cell NHLs involving the marginal zone.

Contribution of lymphatic drainage system in corneal allograft rejection in mice

PURPOSE

To modulate aqueous outflow via the uveoscleral pathway and to determine its influence on corneal graft survival in mice.

METHODS

BALB/c mice received corneal transplants from C3H mice and were placed randomly in three treatment groups: saline, pilocarpine or latanoprost. Three further groups received adjuvant systemic and topical corticosteroids. The kinetics of infiltrating lymphocytes, neutrophils and macrophages in the transplants was investigated in an additional 96 animals. Cytokine expression in the submandibular lymph nodes and spleen was investigated using in-situ hybridization and RNAse protection assay. Tracer experiments were conducted using 99mTC colloidal albumin Nanocoll; count rates were determined in the submandibular lymph nodes, spleen and blood following both subconjunctival and intracameral injection.

RESULTS

Neither pilocarpine nor latanoprost had any influence on aqueous outflow or allograft survival in mice. Neutrophils and macrophages dominated the infiltrating cells 11 days postoperative in both treated and untreated grafts. On postoperative day 13, a greater increase in lymphocytes than in other cell groups was observed in allogeneic grafts. Following allogeneic transplantation, 1% of lymphocytes in ipsilateral submandibular lymph nodes were positive for IFN-gamma. Tracer studies revealed a 16% aqueous outflow via the uveoscleral routes following intracameral injection of Nanocoll; this was increased by 97% with subconjunctival injection.

CONCLUSION

Our data confirm the existence of functional lymphatic drainage via the uveoscleral pathway and conjunctiva in the mouse. Cells within the ipsilateral submandibular lymph node respond to stimuli upstream. This reaction could potentially be manipulated to improve graft survival.

Testicular germ cell tumor with rhabdomyosarcoma successfully treated by disease-adapted chemotherapy including high-dose chemotherapy: case report and review of the literature

Treatment and prognosis have not been well characterized in germ cell tumors (GCT) with a malignant nongerm cell component. Patients with a mediastinal tumor, neural or rhabdomyosarcomatous differentiation and distant metastases have the poorest prognosis. We report a rare case of mixed GCT composed of seminoma, teratoma and rhabdomyosarcoma with the rhabdomyosarcomatous component metastasized into the liver and bone marrow (BM) causing hypercalcemia. The patient was treated with differentiation-tailored chemotherapy (CHT) including a disease-adapted high-dose (HD) CHT regimen with purified autologous PBSCT (APBSCT) and pamidronate. To date, remission has lasted for 4 years. Tumor-adapted CHT including HD-CHT with APBSCT can induce long term remissions in high-risk patients with transformed GCT. A review of the literature is given.

Regression of high-grade gastric B-cell lymphoma after eradication of Helicobacter pylori

Regression of high-grade gastric B-cell lymphoma after eradication of Helicobacter pylori with antibiotic therapy has recently been shown in a very small number of patients. We describe here a patient with a 5-cm polypoid gastric lymphoma, who received a 7-day course of triple therapy when the histopathology was unknown. A second endoscopic examination 4 weeks later showed partial tumor regression without biopsy evidence of malignancy. Endoscopic mucosectomy was performed 8 weeks after the initial diagnosis. Again, in the histological analysis of the specimen, no evidence of B-cell lymphoma could be found. To confirm that the original biopsies were from the same patient, DNA analyses were carried out which gave identical results. This case suggests that a subgroup of primary gastric B-cell lymphomas responds to eradication of H. pylori with antibiotic therapy.

Regulation of the intestinal mucin MUC2 gene expression in vivo: evidence for the role of promoter methylation

In the present work we investigated the in vivo regulation of the mucin gene MUC2, which is overexpressed in all mucinous colorectal carcinomas. The inhibition of methylation by 5-azadeoxycytidine induces de novo expression of MUC2 in the colon carcinoma cell line COLO 205. The expression is retained in xenograft tissue and the cells give rise to MUC2-expressing tumours in nude mice. The strong expression of MUC2 in the normal human goblet cells and in the tissue of human mucinous colorectal carcinomas is associated with the average methylation of about 50% at every investigated CpG site of the MUC2 promoter. In contrast, MUC2 promoter in the non-expressing normal columnar cells and in the non-mucinous carcinoma tissue is methylated to nearly 100%. These data show that (i) low methylation of MUC2 promoter is associated with MUC2 expression in vivo and (ii) the pattern of MUC2 promoter methylation in the normal goblet or columnar cells most closely resembles that in mucinous or non-mucinous colorectal carcinomas, respectively. They indicate that MUC2 expression in vivo is regulated by promoter methylation and support the hypothesis that cells with goblet-like differentiation give rise to mucinous colonic carcinomas.

Secondary ocular involvement in systemic "memory" B-cell lymphocytic leukemia

OBJECTIVE

Recently, B-cell chronic lymphocytic leukemia (B-CLL) has been subdivided into "naive" B-CLL and "memory" B-CLL on the basis of the presence of somatic mutations in the variable region of the immunoglobulin heavy chain gene (IgH). The aim of the current paper was to report the clinical, histopathologic, and molecular biologic findings of intraocular and ocular adnexal involvement in a patient with systemic B-CLL.

DESIGN

Case report.

INTERVENTION

Treatment consisted of systemic chemotherapy, conjunctival biopsies, and, ultimately, enucleation of the left eye.

METHODS

Histopathologic findings of a bone marrow biopsy, the conjunctival biopsies, and the enucleated eye were compared. Further, extensive immunohistochemistry, polymerase chain reaction (PCR) for the detection of heavy chain (IgH) gene rearrangement, gene scan analysis, and DNA sequencing were performed on all tissues.

RESULTS

The tumor manifestations in all specimens demonstrated similar morphologic and immunophenotypic characteristics, consistent with the diagnosis of B-CLL. Immunoglobulin-H PCR and gene scan analysis showed that the B-CLL infiltrates consisted of B cells derived from the same clone. DNA sequencing demonstrated the presence of eight somatic mutations in the variable region of IgH, consistent with "memory" B-CLL.

CONCLUSIONS

Secondary ocular manifestations of B-CLL occur relatively commonly during disease progression. In the current case of memory B-CLL, ocular manifestation of the disease occurred 16 years after initial diagnosis, agreeing with clinical studies suggesting that a less aggressive course is seen in "memory" B-CLL than its counterpart, "naive" B-CLL. Somatic mutation analysis in the variable region of IgH in B-CLL should be part of routine staging investigations to aid the prediction of the individual clinical course in B-CLL patients and to determine new therapeutic strategies.

[Monocytic B-cells represent a new cell population that is mainly recruited from unmutated polyconal naive B-cells]

Monocytoid B-cells appear as a distinct B-cell population in a number of lymphadenopathies but above all in Piringer's lymphadenopathy. Up until now, their assignment to a recognised B-cell subpopulation has not been conclusively achieved. Immunohistological studies have shown characteristics in common with the tumour cells of hairy cell leukemia and also with so-called splenic marginal zone cells. In order to unequivocally clarify their B-cell differentiation stage we have isolated single monocytoid B-cells from immunostained frozen sections and have analysed their immunoglobulin chain gene rearrangements. In addition we have studied the Ig-expression of monocytoid B-cells at both the RNA and protein levels.

Neuroendocrine differentiation is a relevant prognostic factor in stage III-IV colorectal cancer

OBJECTIVE

To determine the prognostic relevance of neuroendocrine differentiation in colorectal cancer.

METHODS

The survival of 116 patients with colorectal cancer of stages III (n = 59) and IV (n = 57) was correlated with the extent of neuroendocrine differentiation. Chromogranin A and synaptophysin were used as neuroendocrine markers. Based on the degree of immunoreactivity for these markers, tumours were classified as 0 (no expression of neuroendocrine markers), 1 (< 2% cells staining positive for neuroendocrine markers) and 2 (> 2% cells staining positive for neuroendocrine markers). Patients were followed up for more than 5 years or until death.

RESULTS

Seven of 59 (11.8%) stage III cancers and 13/57 (22.8%) stage IV cancers belonged to group 2. The 96 patients of groups 0 and 1 lived for 48.9 months, whereas the 20 patients of group 2 survived for only 18.6 months (Kaplan-Meier survival curves, P < 0.001). The difference was most striking in stage III disease with 79.4 months' survival for combined groups 0 and 1, and 38.9 months' survival for group 2 (P < 0.01). Using the multivariate Cox regression model, the presence of more than 2% of cells with neuroendocrine differentiation was found to be an independent prognostic parameter for stage III and IV disease. No correlation was observed between neuroendocrine differentiation and tumour location, grade, depth of invasion or stage.

CONCLUSION

Neuroendocrine differentiation is often seen in colorectal cancer. It is an independent prognostic factor in stage III-IV colorectal cancer.

Down-regulation of BOB.1/OBF.1 and Oct2 in classical Hodgkin disease but not in lymphocyte predominant Hodgkin disease correlates with immunoglobulin transcription

In contrast to the tumor cells (L&H cells) of lymphocyte predominant Hodgkin disease (LPHD), Hodgkin and Reed-Sternberg (HRS) cells of classical Hodgkin disease (cHD) are unable to transcribe immunoglobulin, despite the presence of rearranged immunoglobulin genes. Although initial studies have suggested crippling immunoglobulin gene mutations to be the cause of absent immunoglobulin expression in cHD, recent work of our group has demonstrated an impaired activation of the immunoglobulin promoter as a superior mechanism. As immunoglobulin transcription is mainly regulated by the B-cell transcription factors Oct2 and BOB.1/OBF.1, we analyzed 35 cases of LPHD, 32 cases of cHD, and 2 Hodgkin disease cell lines for the expression of these transcription factors and also in parallel for immunoglobulin expression. Our results demonstrate an absence of Oct2 and/or BOB.1/OBF.1 in cHD and a striking overexpression of Oct2 in LPHD. Immunoglobulin expression was lacking in cHD but present in LPHD. Furthermore, the reintroduction of BOB.1/OBF.1 and Oct2 into cultured HRS cells restored the activity of cotransduced immunoglobulin promoter constructs. Our findings dismiss the concept that the different immunoglobulin expression in cHD and LPHD is due to disrupting mutations of immunoglobulin V genes in cHD but is most likely due to a down-regulation of Oct2 and/or BOB.1/OBF.1. This study further revealed Oct2 as a new and valuable marker for the identification of L&H cells and their distinction from HRS cells. The impairment of immunoglobulin transcription with a down-regulated synthesis of Oct2 and BOB.1/OBF.1 is the first established general recurrent defect found in HRS cells.

Carcinoid tumors of the appendix in children--epidemiology, clinical aspects and procedure

INTRODUCTION

Incidental detection of a carcinoid tumor of the appendix after appendectomy is often accompanied by uncertainty about the further procedure. The tumor frequency in our own patient population, the further course in these children and a practicable follow-up protocol have to be determined.

PATIENTS AND METHODS

All appendectomies performed between January 1, 1982, and December 31, 1996, were retrospectively evaluated with regard to carcinoids, monitoring the clinical course, and follow-up of the patients involved.

RESULTS

A total of 4747 appendectomies were performed, 8 children had a histologically manifest carcinoid (0.169%). All patients were symptom-free in the further course, no metastases or signs of a carcinoid were documented during a mean follow-up period of 6.6 years.

CONCLUSION

The youngest patient with a metastasizing carcinoid tumor of the appendix reported in the literature was 19 years old. Nevertheless, all younger patients should undergo regular follow-ups; this is done in our department by serum serotonin and chromogranin A determination.

CD30(+) anaplastic large cell lymphoma: a review of its histopathologic, genetic, and clinical features

Anaplastic large cell lymphoma (ALCL) represents a generally recognized group of large cell lymphomas. Defining features consist of a proliferation of predominantly large lymphoid cells with strong expression of the cytokine receptor CD30 and a characteristic growth pattern. With the use of molecular and clinical criteria, 3 entities of ALCL have been identified: primary systemic anaplastic lymphoma kinase (ALK)(+) ALCL, primary systemic ALK(-) ALCL, and primary cutaneous ALCL. ALK expression is caused by chromosomal translocations, most commonly t(2;5). ALK(+) ALCL predominantly affects young male patients and, if treated with chemotherapy, has a favorable prognosis. It shows a broad morphologic spectrum, with the "common type," the small cell variant, and the lymphohistiocytic variant being most commonly observed. The knowledge of the existence of these variants is essential in establishing a correct diagnosis. ALK(-) ALCL occurs in older patients, affecting both genders equally and having an unfavorable prognosis. The morphology and the immunophenotype of primary cutaneous ALCL show an overlap with that of lymphomatoid papulosis. Both diseases have an excellent prognosis, and secondary systemic dissemination is only rarely observed. The described ALCL entities usually derive from cytotoxic T cells. In contrast, large B-cell lymphomas with anaplastic morphology are believed to represent not a separate entity but a morphologic variant of diffuse large B-cell lymphoma. Malignant lymphomas with morphologic features of both Hodgkin disease and ALCL have formerly been classified as Hodgkin-like ALCL. Recent immunohistologic studies, however, suggest that ALCLs Hodgkin-like represent either cases of tumor cell-rich classic Hodgkin disease or (less commonly) ALK(+) ALCL or ALK(-) ALCL. (Blood. 2000;96:3681-3695)

Expression of SIALYL-Le(x) antigen defined by MAb AM-3 is an independent prognostic marker in colorectal carcinoma patients

Expression of mucin-bound sialyl-Le(x) antigen during the progression of colorectal carcinoma and its potential prognostic value were analysed in sections of tumours from 182 patients with a documented follow-up by immunohistochemistry using the monoclonal antibody (MAb) AM-3. Two groups of colonic carcinomas with weak (n = 79) and strong (n = 103) sialyl-Le(x) expression were discerned. The percentage of strongly expressing tumours increased with the progression of the disease (UICC stage I = 10%, stage II = 46%, stage III = 63%, stage IV = 68%, p < 0.0001). Seventy-four percent of patients with carcinomas exhibiting a strong sialyl-Le(x) expression but only 34% of patients with weak sialyl-Le(x) expression died of the disease (p = 0.0026). In multivariate analysis, strong sialyl-Le(x) expression increased the relative risk of cancer-related death 3.8-fold (95% CI = 1.8-7.9, p = 0.00034). The separate analyses of patients in UICC stage II (n = 56), III (n =5 9) and IV (n = 57) revealed that strong sialyl-Le(x) expression was associated with a reduction of the 5-year overall survival rate in UICC stage II (84% vs. 54%, p = 0.0013) and in stage III patients (86% vs. 35%, p = 0.0008) after curative resection but was not relevant in patients with distant metastases. In conclusion, the strong expression of sialyl-Le(x) antigen defined by the MAb AM-3 in colorectal carcinomas is an independent unfavourable prognostic factor after curative resection in stage II and III patients. The predictive power of the sialyl-Le(x) expression may be helpful to define subgroups of patients at high risk for whom preventive adjuvant therapy can be selectively applied before the occurrence of detectable metastases.

Pathology of intestinal lymphomas

The advent of immunohistological and molecular techniques has enabled the comprehensive characterization of many lymphoma entities. Furthermore, it has increased the consensus in lymphoma classification among pathologists. In this review we describe the pathological features of primary intestinal lymphomas classified according to the revised European-American classification of lymphoid neoplasms. The majority of primary intestinal lymphomas are of B-cell lineage and most of these are high-grade tumors. By morphology they may be classified as diffuse large B-cell lymphomas of centroblastic, immunoblastic or plasmablastic type and Burkitt lymphomas. The latter occur predominantly in the terminal ileum and affect children or young adults. Low-grade extra-nodal marginal-zone lymphoma of the mucosa-associated lymphoid tissue (MALT) type and, less frequently, follicular center-cell lymphomas are the low-grade B-cell lymphomas most commonly observed in this region. The first mentioned tumor and its specific intestinal variant, alpha-chain disease or immunoproliferative small intestinal disease are well known for their indolent clinical course. Primary intestinal mantle-cell lymphoma often presents as multiple lymphomatous polyposis and similarly to its node-based equivalent is associated with an unfavorable prognosis. Most primary intestinal T-cell lymphomas display a characteristic immunophenotype, particular histological features with prominent epitheliotropism and are often associated with celiac disease indicating that these tumors form a specific lymphoma type. It has been termed intestinal T-cell lymphoma or enteropathy-type T-cell lymphoma. Clinically, these are aggressive diseases with a high mortality rate. In summary, primary intestinal lymphomas consist of several entities which display distinct clinicopathological features thus confirming the relevance of lymphoma typing.

Neonatal onset of rash in Still's disease

We report a neonate with a rash that appeared on the second day of life in association with elevated body temperatures and increased C-reactive protein levels. The rash was evanescent and recurred on a daily basis during the first year of life. At 15 months, the infant developed swelling of the right knee joint. Early-onset systemic juvenile rheumatoid arthritis can mimic congenital infections and should be considered in the differential diagnosis of neonatal exanthemas.

Expression of the CD30 antigen in non-lymphoid tissues and cells

Originally, expression of the CD30 antigen was shown to be typical of the tumour cells of Hodgkin's disease (HD) and of anaplastic large cell lymphomas (ALCLs). In reactive lymphoid tissue, CD30 is expressed only in a small population of activated lymphoid blasts. Since then, several reports have been published describing CD30 expression in non-lymphoid tissues and malignancies, such as embryonal carcinomas (ECs), seminomas, cultivated macrophages, two histiocytic neoplasms, decidual cells, and mesotheliomas. As CD30 detection is important in the differential diagnosis of HD and ALCL, the expression of CD30 in different non-lymphoid tissues was re-evaluated by immunohistology and in situ hybridization. Extra-lymphoid CD30 expression was found in 48/51 cases of EC or EC components of germ cell tumours, in decidual cells of 1/10 cases, in activated mesothelium in 16/28 pleural and peritoneal effusions, and in small foci of tumour cells in 2/8 mesotheliomas. CD30 expression was not confirmed in 27 germ cell tumours of the testis without an EC component nor in cultivated macrophages and 17 histiocytic malignancies. The knowledge of these CD30 expression patterns is important for the immunohistological differential diagnosis of anaplastic tumours. The absence of CD30 expression in reactive and neoplastic macrophages does not favour the concept that HD and ALCL are derived from these cells.

Defective post-transcriptional processing of MUC2 mucin in ulcerative colitis and in Crohn's disease increases detectability of the MUC2 protein core

Ulcerative colitis (UC) and, to a lesser extent, Crohn's disease (CD) are associated with a reduction of the protective mucus layer in the large intestine; the role of this alteration in the pathogenesis of either disease is, however, not clear. To learn more about the molecular mechanism of the alteration of the mucus layer, the expression of the main intestinal mucin, MUC2, was investigated in relation to inflammation and dysplasia. Formalin-fixed, paraffin-embedded biopsies from 70 patients with UC and 16 patients with CD, and 13 biopsies from normal colonic mucosa, were used for detection of MUC2 mRNA by in situ hybridization with the SMUC41 probe, and MUC2 protein by immunohistochemistry with the antibody CCP58. The steady-state concentration of MUC2 mRNA was not affected by UC or CD. By contrast, the amount of the detectable MUC2 protein, assessed as the immunoreactive score (IRS), was significantly (p<0. 0001) increased in UC (IRS=8.0+/-3.8) and CD (8.0+/-3.7), compared with the normal colonic mucosa (IRS=2.0+/-1.5). This alteration occurred in the inactive phase of inflammation and persisted in the active phase of the disease. It was also observed during bacterial or protozoal inflammation (n=7). The IRS values did not correlate with the grade of inflammation or dysplasia. Simultaneous histochemistry with high iron diamine and immunohistochemistry indicated that the increase of detectable MUC2 is concomitant with low mucin sulphation in the same cells. These data indicate that the strong MUC2 protein staining in colonic mucosa of patients with UC or CD is due to a long-term alteration of the post-transcriptional modification of the MUC2 molecule, leading to its better detectability by the anti-MUC2 antibody CCP58. This alteration, induced by the inflammatory process, may affect the gel thickness and may contribute to a protracted autoimmune response.

[The many faces of anaplastic large cell lymphoma]

Fifteen years after their first description by one of the authors (HS) anaplastic large cell lymphoma (ALC-lymphoma, ALCL) now represents a generally accepted group of large cell lymphomas. Essential defining features comprise of a proliferation of large lymphoid cells with strong expression of the cytokine receptor CD30 and a characteristic growth pattern. Using molecular and clinical criteria three entities of ALC-lymphoma have been identified: primary systemic anaplastic lymphoma kinase (ALK)-positive ALC-lymphoma, primary systemic ALK-negative ALC-lymphoma and primary cutaneous ALC-lymphoma. The ALK expression in the primary systemic ALC-lymphoma entity is caused by chromosomal translocations, most commonly t(2;5), and can nowadays be reliably detected by immuno-histology. ALK-positive ALC-lymphoma predominantly affects young male patients and if treated with chemotherapy has a favourable prognosis. They show a broad morphological spectrum, with the "common type", the small cell variant and the lymphohistiocytic variant being most commonly observed. The knowledge of the existence of these variants is essential in establishing the correct diagnosis. ALK-negative ALC-lymphomas occur in older patients, equally affecting both genders and have an unfavorable prognosis. The morphology and the immuno-phenotype of primary cutaneous ALC-lymphoma shows an overlap with that of lymphomatoid papulosis. Both diseases have an excellent prognosis and secondary systemic dissemination is only rarely observed. The ALC-lymphomas described above derive from T cells and are generally accepted as biological entities. In contrast, large B-cell-lymphomas with anaplastic morphology are now believed not to represent an own entity but a morphologic variant of diffuse large B-cell lymphoma. Malignant lymphomas with morphological features of both Hodgkin- and ALC-lymphoma have formerly been classified as ALCL Hodgkin-like. Recent immuno-histological analysis of these cases however suggests that ALCL Hodgkin-like does not represent an own lymphoma entity. Most of these cases are likely to be examples of tumor cell rich classical Hodgkin lymphoma, while a minority of these cases appear to fall either into the category of ALK-positive or ALK-negative ALC-lymphoma.

[Hodgkin lymphoma. Classification and pathogenesis]

In the last few years our understanding of Hodgkin's lymphoma (HL) has enormously progressed. Molecular analysis has revealed that almost all cases of this disease are clonal B cell neoplasms, therefore the term Hodgkin's lymphoma instead of Hodgkin's disease is being proposed in the new WHO classification. Lymphocyte predominance HL (LPHL) differs in respect to morphology, immunophenotype and clinical features from the other forms of HL and represents its own distinct entity. In addition to morphologic features (nodularity, presence of L&H cells) the immuno-phenotype of tumor cells is most important in establishing a diagnosis of LPHL, and particularly in differentiating LPHL from the other forms of HL. The remaining forms of HL (nodular sclerosis, mixed cellularity, lymphocyte depletion) display a mostly identical antigen profile and similar clinical characteristics, they are therefore grouped together in the REAL classification under the heading of classical HL. Recent immuno-histological analysis have revealed that one third of HL cases, which formerly were classified as LPHL, display the immuno-phenotype of classical HL. These cases are now considered to represent examples of classical HL and termed nodular lymphocyte rich classical HL. According to retrospective clinico-pathological analysis, the biological behaviour of this newly identified form of classical HL also differs from LPHL. Differences between classical HL and LPHL also occur on the molecular level. Thus LPHL often displays ongoing mutations of the immunoglobulin genes, and the tumor cells express immunoglobulin protein and transcripts, while these characteristics are absent in classical HL. Since peripheral B cells that do not express immunoglobulins die from apoptosis, these findings imply that the regulation of apoptosis is defective in Hodgkin and Sternberg Reed cells. Several laboratories are currently working intensely to clarify the defective apoptosis pathway in HL.

[Clinico-pathologic forms of peripheral T-and NK-cell lymphomas]

Malignant lymphomas, originating from peripheral T or NK cells, are rare tumours in Europe and account for less than 10% of all malignant lymphomas. In this review, the salient features of the more frequently occurring entities derived from T or NK cells will be presented. Nasal NK/T cell lymphoma is mainly found in the nose and paranasal sinuses and often, but not always, display an angiocentric growth pattern leading to coagulation necrosis. The tumor cells consistently express CD56, CD2 and the EBER molecules encoded by the Epstein-Barr virus. Clonal T cell receptor gene rearrangements are often absent indicating, in the majority of cases, a derivation of these tumors from NK cells. Enteropathy-type intestinal T-cell lymphomas often arise in patients with celiac disease and have a dismal prognosis. The tumour cells express T cell antigens, CD103 and cytotoxic molecules, but are negative for CD4. Approximately 20% of the cases display CD56 mostly in combination with CD8. Recently, an early purely intraepithelial form of this tumour was identified. Histologically these cases resemble celiac disease, however the intraepithelial lymphocytes often exhibit an abnormal immunophenotype with absent CD8 and T-cell-receptor protein expression, and, they are clonal by molecular analysis. Clinically, the patients suffer from refractory sprue or ulcerative jejunitis. The prognosis is bad with the patients often dying from malnutrition or an invasive tumour-forming T-cell lymphoma. Angioimmunoblastic T-cell lymphoma is defined by characteristic morphological findings (atypical lymphoid cells in part with pale cytoplasm, arborizing high endothelial venules and large FDC-meshworks) as well as clinical features (systemic symptoms, signs of a dys-regulated immune response). Peripheral T-cell lymphomas, that do not fit into a distinct entity, are classified in the REAL and the new WHO classifications as peripheral T-cell lymphomas unspecified. These display a broad morphological spectrum (including the T-cell lymphomas of different cell sizes, Lennert's lymphoma and T-zone lymphoma of the Kiel-classification) and in general are clinically aggressive.

Hodgkin and reed-sternberg cells represent an expansion of a single clone originating from a germinal center B-cell with functional immunoglobulin gene rearrangements but defective immunoglobulin transcription

Single cell studies aimed at clarifying the nature and clonality of Hodgkin and Reed-Sternberg (HRS) cells of classical Hodgkin's disease (HD) have so far produced conflicting results. Using an improved single cell procedure, the HRS cells of 25 patients with nodular sclerosing HD lacking B- and T-cell antigens, with and without Epstein-Barr virus infection, were analyzed for the presence of immunoglobulin (Ig) gene rearrangements. One patient with HD developed follicular lymphoma 2 years later. Both lymphomas originated from a common precursor identified as a germinal center B cell. The data show that all but one of the investigated cases harbored rearranged Ig genes, which were clonal in all instances and carried a high load of somatic mutations. The Ig coding capacity was preserved in 18 of the 24 cases (75%) with rearrangements. However, expression of Ig messenger RNA was not detectable in the HRS cells with the exception of Ig kappa light chain expression in some tumor cells of 1 case. The lack of Ig gene transcription in HRS cells was confirmed by analyzing the HD cell lines L428 and KM-H2 in transient transfection experiments. An Ig promoter/enhancer reporter construct showed virtually no activity in these cells compared to 5 control B-cell lines. We conclude that (1) classical HD is a B-cell lymphoma in most instances, (2) HRS cells are clonal without any exception, (3) they are derived from germinal center B-cells that (4) mostly lack crippling mutations but (5) have consistently lost their Ig gene transcription ability, due to functional defects in the Ig gene regulatory elements. (Blood. 2000;95:1443-1450)

The prognostic significance of tumor vascularization in patients with localized colorectal cancer

Angiogenesis is essential for tumor growth and metastasis, and vascular density is known as an independent prognostic factor in several tumor entities. We studied the prognostic relevance of vascular density in colorectal cancer, examining 146 patients treated surgically for cure. Tumor sections were immunostained with JC70, an endothelial cell marker. Microvessel quantification used light microscopy. The slides were scanned at a low magnification, and individual microvessel counts were made on a x200 field in the area of the most dense neovascularization. Vascular density was found to be 75+/-27/visual field and to be independent of age, sex, pT and pN categories, tumor recurrence, and overall survival. Overall survival in the subgroup of patients with tumor recurrence was significantly shorter with tumors of greater vessel density (>75) than in those of less vessel density (<75). Multivariate analysis showed microvessel count to be an independent prognostic factor for the overall survival rate of patients with tumor recurrence; among these patients there was also a significant difference in the relapse-free survival rates between the hypovascular and the hypervascular groups. Our findings suggest that the microvessel density of the primary tumor determines the speed of tumor recurrence after metastatic disease has been triggered by other, unknown mechanisms. Although tumor vascularization can be linked to the aggressiveness of colorectal cancer, it has no value as a new prognostic marker in clinical practice.

Classical Hodgkin's disease and follicular lymphoma originating from the same germinal center B cell

PURPOSE

Classical Hodgkin's disease and non-Hodgkin's B-cell lymphoma occasionally occur in the same patient. To clarify whether these different diseases share a common precursor cell, we analyzed the immunoglobulin rearrangements in tumor cells of the classical Hodgkin's disease and the follicular lymphoma that developed in the same patient 2 years apart.

PATIENTS AND METHODS

Polymerase chain reaction (PCR) for the detection of rearranged immunoglobulin genes was carried out on single Reed-Sternberg cells and on whole tissue DNA extracted from the follicular lymphoma. PCR products were sequenced and compared with each other and with germ line immunoglobulin variable segments. Immunoglobulin heavy- and light-chain transcripts were analyzed by radioactive in-situ hybridization.

RESULTS

The same monoclonal immunoglobulin gene rearrangement was found in both neoplasms. The variable region of the immunoglobulin heavy-chain genes of the Reed-Sternberg and of the follicular lymphoma cells were differently mutated, but six somatic mutations were shared by both lymphoma cells. Although the coding capacity of the immunoglobulin genes was preserved in both neoplastic cell populations, immunoglobulin heavy- (mu) and light- (kappa) chain expression was restricted to the follicular lymphoma cells, except for small amounts of kappa light-chain mRNA in some Reed-Sternberg cells.

CONCLUSIONS

The neoplastic cells of the Hodgkin's disease and the follicular lymphoma that occurred in this patient derived from a common precursor B cell. Its differentiation stage could be identified as that of a germinal center B cell. Thus, transforming events can be more important than the cell of origin in determining a disease entity.

Frequent expression of the B-cell-specific activator protein in Reed-Sternberg cells of classical Hodgkin's disease provides further evidence for its B-cell origin

The neoplastic cells of classical Hodgkin's disease (cHD), ie, Hodgkin and Reed-Sternberg cells (HRS cells), contain clonally rearranged Ig genes, but are dissimilar to normal B cells in that they mostly do not display B-cell antigens such as CD20 or CD19. The transcription factor B-cell-specific activator protein (BSAP) influences numerous B-cell functions such as B-cell antigen expression, Ig expression, and class switch. We analyzed the expression of BSAP in cHD and control tissues by isotopic in situ hybridization and immunohistochemistry to determine whether BSAP is expressed in HRS cells and, if so, whether it may be involved in the genesis of the abnormal phenotype of these cells. Both in normal lymphoid tissue and non-Hodgkin lymphomas, BSAP transcripts and protein were almost exclusively found in B cells and B-cell lymphomas (40 cases), but were absent from the tumor cells of T-cell neoplasms (41 cases), including 19 cases of anaplastic large cell lymphoma of T- and null-cell type. Among cHD, variable numbers of HRS cells exhibited BSAP transcripts (22 of 25 cases) and protein (28 of 31 cases). Our findings show that BSAP is sufficiently specific to serve as B-cell marker. BSAP expression in HRS cells provides further strong evidence for a frequent B-cell origin of cHD and helps distinguish this disease from anaplastic large cell lymphoma of T- and null-cell type. Because BSAP is much more frequently expressed in HRS cells than the conventional B-cell antigens, the abnormal immunophenotype of HRS cells with frequent absence of B-cell antigens does not appear to be due to absent BSAP expression.

Overexpression of I kappa B alpha without inhibition of NF-kappaB activity and mutations in the I kappa B alpha gene in Reed-Sternberg cells

The transcription factor NF kappa B (NF-kappaB) mediates the expression of numerous genes involved in diverse functions such as inflammation, immune response, apoptosis, and cell proliferation. We recently identified constitutive activation of NF-kappaB (p50/p65) as a common feature of Hodgkin/Reed-Sternberg (HRS) cells preventing these cells from undergoing apoptosis and triggering proliferation. To examine possible alterations in the NF-kappaB/IkappaB system, which might be responsible for constitutive NF-kappaB activity, we have analyzed the inhibitor I kappa B alpha (IkappaBalpha) in primary and cultured HRS cells on protein, mRNA, and genomic levels. In lymph node biopsy samples from Hodgkin's disease patients, IkappaBalpha mRNA proved to be strongly overexpressed in the HRS cells. In 2 cell lines (L428 and KM-H2), we detected mutations in the IkappaBalpha gene, resulting in C-terminally truncated proteins, which are presumably not able to inhibit NF-kappaB-DNA binding activity. Furthermore, an analysis of the IkappaBalpha gene in single HRS cells micromanipulated from frozen tissue sections showed a monoallelic mutation in 1 of 10 patients coding for a comparable C-terminally truncated IkappaBalpha protein. We suggest that the observed IkappaBalpha mutations contribute to constitutive NF-kappaB activity in cultured and primary HRS cells and are therefore involved in the pathogenesis of these Hodgkin's disease (HD) patients. The demonstrated constitutive overexpression of IkappaBalpha in HRS cells evidences a deregulation of the NF-kappaB/IkappaB system also in the remaining cases, probably due to defects in other members of the IkappaB family.

T-cell and T/natural killer-cell lymphomas involving ocular and ocular adnexal tissues: a clinicopathologic, immunohistochemical, and molecular study of seven cases

OBJECTIVE

Lymphomas of the eye and its adnexa are frequently of B lineage. This study aims to characterize the clinical and histopathologic features of the rare non-B-cell non-Hodgkin lymphomas (NHL) of these locations.

DESIGN

Retrospective, noncomparative case series.

PARTICIPANTS

Seven cases of T- and T/NK-cell lymphomas involving the ocular and ocular adnexal tissues.

METHODS

A morphologic, immunohistochemical, and molecular analysis (polymerase chain reaction) of each of the tumors was undertaken. The lesions were classified according to the Revised European-American Lymphoma (REAL) classification. The clinical and follow-up data were collected.

RESULTS

The patients included four women and three men ranging in age from 32 to 88 years (mean, 63 years). The presenting ophthalmic symptoms varied from a small nodule on the upper eyelid and conjunctival swellings to dramatic loss of vision associated with gross protrusion of the globe. Five of the cases presented were secondary manifestations of a systemic lymphoma in ocular tissues; two cases represented primary disease. Three cases were "peripheral T-cell lymphomas (PTCL), unspecified" with positivity for CD3, CD8, and betaF1 and negativity for CD56. Two cases were CD3+, CD30+, and CD56- and were classified as "anaplastic large-cell lymphomas of T-cell type" (T-ALCL). The remaining two cases showed an immunophenotype of CD3+, CD56+, and betaF1- and proved to contain Epstein-Barr virus (EBV) by in situ hybridization, consistent with "T/natural killer (NK)-cell lymphoma of nasal type." Clonal T-cell populations were shown in all three of the PTCLs by Southern blot (n = 1) and polymerase chain reaction (n = 2) for the T-cell receptor gamma and beta genes in one case of ALCL but not in the T/NK-cell lymphomas. Five patients died within 2 years; only two patients (one primary PTCL and one cutaneous T-ALCL) were disease free at 4 and 5 years' follow-up, respectively.

CONCLUSION

This study shows that a heterogeneous group of T-cell lymphomas can involve the eye and its adnexal tissue. Most T-cell neoplasms are secondary manifestations of systemic disease and carry a poor prognosis. These findings, in conjunction with published data on ocular B-NHL, also indicate that immunophenotypic differentiation between T- and B-NHL in these locations is of clinical importance.

Monocytoid B cells are distinct from splenic marginal zone cells and commonly derive from unmutated naive B cells and less frequently from postgerminal center B cells by polyclonal transformation

Monocytoid B cells represent a morphologically conspicuous B-cell population that constantly occurs in Toxoplasma gondii-induced Piringer's lymphadenopathy. Although widely believed to be closely related to splenic marginal zone B cells, neither this relationship, nor the B-cell differentiation stage of monocytoid B cells, nor their cellular precursors have been established. We have therefore examined monocytoid B cells for their expression of B-cell differentiation markers and the Ig isotypes at the RNA and protein level as well as for rearranged Ig heavy chain (H) genes and somatic mutations within the variable (V) region. The results obtained were compared with the corresponding features of other B-cell populations. The monocytoid B cells displayed immunophenotypical differences to all other B-cell populations. IgM and IgD expression was absent from most monocytoid B cells at the RNA and protein levels. Unrelated (polyclonal) Ig rearrangements were found in 85 of the 95 cells studied. Seventy-four percent of the rearranged VH genes were devoid of somatic mutations, whereas the remaining 26% carried a low number of somatic mutations. The majority of these showed no significant signs of antigen selection. This finding in conjunction with the predominantly unrelated Ig gene rearrangements indicates that most monocytoid B cells arise not by clonal proliferation but by transformation of polyclonal B cells. The B cells undergoing a monocytoid B-cell transformation are in the majority (74%) naive B cells, and only a minority are (26%) non-antigen-selected postgerminal center B cells. Thus, our data show that monocytoid B cells represent a distinct B-cell subpopulation.

Hodgkin/Reed-Sternberg cells induce fibroblasts to secrete eotaxin, a potent chemoattractant for T cells and eosinophils

Hodgkin's disease is histopathologically characterized by the relative scarcity of neoplastic Hodgkin and Reed-Sternberg cells and for yet unknown reasons by an abundant reactive background of T lymphocytes and often eosinophils. Eotaxin is a CC-chemokine attracting eosinophils and T helper 2 (Th2) cells in allergic inflammation. We now report that eotaxin is strongly expressed in fibroblasts of Hodgkin's disease tissues, whereas Hodgkin/Reed-Sternberg cells do not express this chemokine. In tissue culture, Hodgkin's disease tumor cells induce eotaxin expression in cocultured dermal fibroblasts in a concentration leading to a specific chemotactic response of a Th2 cell clone. Production of tumor necrosis factor-alpha (TNF-alpha) by Hodgkin/Reed-Sternberg cells appears to be responsible for this induction, because blocking of TNF-alpha by neutralizing antibodies prevented fibroblast eotaxin expression. Our data suggest that eotaxin is involved in the pathobiology of Hodgkin's disease by contributing to eosinophil and T-lymphocyte recruitment.

Defective post-transcriptional processing of MUC2 mucin in ulcerative colitis and in Crohn's disease increases detectability of the MUC2 protein core

Ulcerative colitis (UC) and, to a lesser extent, Crohn's disease (CD) are associated with a reduction of the protective mucus layer in the large intestine; the role of this alteration in the pathogenesis of either disease is, however, not clear. To learn more about the molecular mechanism of the alteration of the mucus layer, the expression of the main intestinal mucin, MUC2, was investigated in relation to inflammation and dysplasia. Formalin-fixed, paraffin-embedded biopsies from 70 patients with UC and 16 patients with CD, and 13 biopsies from normal colonic mucosa, were used for detection of MUC2 mRNA by in situ hybridization with the SMUC41 probe, and MUC2 protein by immunohistochemistry with the antibody CCP58. The steady-state concentration of MUC2 mRNA was not affected by UC or CD. By contrast, the amount of the detectable MUC2 protein, assessed as the immunoreactive score (IRS), was significantly (p<0. 0001) increased in UC (IRS=8.0+/-3.8) and CD (8.0+/-3.7), compared with the normal colonic mucosa (IRS=2.0+/-1.5). This alteration occurred in the inactive phase of inflammation and persisted in the active phase of the disease. It was also observed during bacterial or protozoal inflammation (n=7). The IRS values did not correlate with the grade of inflammation or dysplasia. Simultaneous histochemistry with high iron diamine and immunohistochemistry indicated that the increase of detectable MUC2 is concomitant with low mucin sulphation in the same cells. These data indicate that the strong MUC2 protein staining in colonic mucosa of patients with UC or CD is due to a long-term alteration of the post-transcriptional modification of the MUC2 molecule, leading to its better detectability by the anti-MUC2 antibody CCP58. This alteration, induced by the inflammatory process, may affect the gel thickness and may contribute to a protracted autoimmune response.

ALK+ lymphoma: clinico-pathological findings and outcome

A distinct pathologic entity (ALK+ lymphoma) that is characterized by expression of the anaplastic lymphoma kinase (ALK) protein has recently emerged within the heterogeneous group of CD30(+) anaplastic large-cell lymphomas. Information on clinical findings and treatment outcome of ALK+ lymphoma is still limited, and no data are available concerning the value of the International Prognostic Index when applied to this homogeneous disease entity. To clarify these issues, a recently developed monoclonal antibody ALKc (directed against the cytoplasmic portion of ALK) was used to detect expression of the ALK protein in paraffin-embedded biopsies from 96 primary, systemic T/null anaplastic large-cell lymphomas, and the ALK staining pattern was correlated with morphological features, clinical findings, risk factors (as defined by the International Prognostic Index), and outcome in 78 patients (53 ALK+ and 25 ALK-). Strong cytoplasmic and/or nuclear ALK positivity was detected in 58 of 96 ALCL cases (60.4%), and it was associated with a morphological spectrum (common type, 82.7%; giant cell, 3.5%; lymphohistiocytic, 8. 6%; and small cell, 5.2%) that reflected the ratio of large anaplastic elements (usually showing cytoplasmic and nuclear ALK positivity) to small neoplastic cells (usually characterized by nucleus-restricted ALK expression). Clinically, ALK+ lymphoma mostly occurred in children and young adults (mean age, 22.01 +/- 10.87 years) with a male predominance (male/female [M/F] ratio, 3.0) that was particularly striking in the second-third decades of life (M/F ratio, 6.5) and usually presented as an aggressive, stage III-IV disease, frequently associated with systemic symptoms (75%) and extranodal involvement (60%), especially skin (21%), bone (17%), and soft tissues (17%). As compared with ALK+ lymphoma, ALK- cases occurred in older individuals (mean age, 43.33 +/- 16.15 years) and showed a lower M/F ratio (0.9) as well as lower incidence of stage III-IV disease and extranodal involvement at presentation. Overall survival of ALK+ lymphoma was far better than that of ALK- anaplastic large-cell lymphoma (71% +/- 6% v 15% +/- 11%, respectively). However, within the good prognostic category of ALK+ lymphoma, survival was 94% +/- 5% for the low/low intermediate risk group (age-adjusted International Prognostic Index, 0 to 1) and 41% +/- 12% for the high/high intermediate risk group (age-adjusted International Prognostic Index, >/=2). Multivariate analysis identified ALK expression and the International Prognostic Index as independent variables that were able to predict survival among T/null primary, systemic anaplastic large-cell lymphoma. Thus, we suggest that such parameters should be taken into consideration for the design of future clinical trials.

[Highly differentiated liposarcoma of the larynx]

Liposarcomas are very rare malignancies in the larynx. At present only a few case reports have been described in the available literature. These cases have been highly differentiated liposarcomas, just like our case. The unremarkable clinical picture of these tumors is that of a soft, lipomatous, smooth limited tumor. Findings first appear to be consistent with a lipoma and not a malignancy. Our case of a 23-year-old man is the youngest patient with a laryngeal liposarcoma described thus far. We discuss the surgical procedure used, especially in view of a local recurrence rate of approximately 60%, as well as additional radiotherapy. The treatment of choice is extensive local tumor resection. Chemotherapy is presently not useful for highly differentiated liposarcomas.

FasL is more frequently expressed in liver metastases of colorectal cancer than in matched primary carcinomas

Colorectal carcinoma cells have recently been shown to express Fas ligand (FasL). This ligand could allow the tumour cells to evade activated tumour-infiltrating lymphocytes (TILs) by inducing their apoptosis and would thus promote tumour survival and possibly metastasis formation. To test this hypothesis in vivo we analysed the expression of FasL mRNA and protein in paired tissue samples of normal colonic mucosa (N), primary colorectal carcinomas (T) and their metastases (M) from a total of 21 patients by four different methods. Additionally, the presence and activation status of infiltrating lymphocytes, which might contribute to the total amount of FasL in the tissue, was determined by semiquantitative reverse transcription-polymerase chain reaction (RT-PCR) in the same samples. The frequency of FasL detection was 30-40% in T and was 60-100% in M, depending on the sensitivity of the method. Simultaneously, the amount of CD25 mRNA, used as a measure of the number of activated TILs, was in 90% of patients lower in M than in T. The increased frequency of FasL detection in liver metastases was therefore not due to the presence of activated TILs. We conclude that metastasizing subpopulations of colorectal tumour cells express FasL more frequently than the primary carcinomas and may be able to eliminate activated TILs in vivo via Fas/FasL-induced apoptosis or other hitherto unknown mechanisms.

Immunoglobulin VH gene expression among extranodal marginal zone B-cell lymphomas of the ocular adnexa

PURPOSE

Most lymphomas of the ocular adnexa are primary extranodal non-Hodgkin's lymphomas of the B-cell type, with the most common lymphoma subtype being the extranodal marginal-zone B-cell lymphoma (EMZL). Analysis of somatic mutations in the variable (V) region of the Ig heavy (H)-chain gene segment suggests that EMZL development in other locations is dependent on antigen stimulation. The purpose of this study was to analyze the presence of somatic hypermutations in clonally rearranged Ig H-chain V genes of this lymphoma entity in the ocular adnexa and to estimate whether the mutation pattern is compatible with antigen selection.

METHODS

Twenty-six cases of EMZL of the ocular adnexa were diagnosed on the basis of morphology, histology, and immunohistology. A nested polymerase chain reaction (PCR) was performed on DNA extracted from paraffin sections. The isolated PCR products were sequenced and compared with published VH germline segments to determine the number of somatic mutations in the complementarity-determining region (CDR) 2 and framework (FW) region 3.

RESULTS

The number of somatic mutations in the cases of EMZL varied between 0 and 24: Five cases involved 0 to 3 somatic mutations, and the remaining 21 cases involved 4 to 24 mutations. Based on the ratio of replacement (R) to silent (S) mutations in the CDR2 or FW3 regions, antigen selection seems to have occurred in 60% of ocular adnexal EMZL. The VH3 family was the most commonly expressed germline VH family (54%), followed by VH4 (23%), with biased usage of the latter. Some germline VH1 genes used included DP-8, DP-10, DP-53, DP-63 (VH4.21), and DP-49, which are frequently used by autoantibodies (e.g., rheumatoid factors) and natural autoantibodies.

CONCLUSIONS

EMZLs of the ocular adnexa have an Ig H-chain mutation pattern that supports the concept that they represent a clonal expansion of post-germinal-center memory B-cells in most instances. In two thirds of cases, antigen selection may have occurred, and autoantibodies may have a role in their development.

Altered tight junction structure contributes to the impaired epithelial barrier function in ulcerative colitis

BACKGROUND & AIMS

Mechanisms of diarrhea in ulcerative colitis (UC) are still unknown. Functional and structural characterization of epithelial barrier and transport properties in ulcerative colitis (UC) was performed.

METHODS

Inflamed sigmoid colon epithelium from UC patients was studied by alternating current impedance analysis to determine the pure epithelial resistance as a measure of intestinal barrier function. Tight junction (TJ) structure was investigated by freeze-fracture electron microscopy.

RESULTS

Although total wall resistance was reduced in UC by 50%, impedance analysis uncovered a much more pronounced barrier defect. Epithelial resistance decreased from 95 +/- 5 to 20 +/- 3 omega3. cm2, which in conventional analysis is masked by an increase in subepithelial resistance from 14 +/- 1 to 36 +/- 3 omega3. cm2 caused by inflammation. This was paralleled by a change in epithelial cell TJ structure in UC. Strand count decreased from 6.94 +/- 0.25 to 4.76 +/- 0.47 at the surface and from 7.26 +/- 0.31 to 5.46 +/- 0.37 in the crypts.

CONCLUSIONS

The inflamed colonic mucosa in UC has an impaired barrier function that is much more pronounced than previously assumed. An altered TJ structure contributes to this barrier defect which, because of increased back leak, can reduce net ion transport. Thus, a leak-flux mechanism contributes to the diarrhea in UC.

Frequent expansion of Epstein-Barr virus (EBV) infected cells in germinal centres of tonsils from an area with a high incidence of EBV-associated lymphoma

Burkitt's lymphoma (BL) and Hodgkin's disease (HD) occurring in developing regions are frequently associated with Epstein-Barr virus (EBV) infection and have a high incidence in childhood. Recent genotyping studies indicate that the tumour cells of both neoplasms represent B cells that contain somatically mutated immunoglobulin heavy chain genes. This implies that the precursors of these neoplasms have participated in the germinal centre (GC) reaction. We therefore presumed that normal lymphoid tissues from children living in developing regions would harbour an increased number of EBV-infected cells within the GC, when compared with children living in industrialized nations. To test this hypothesis, hyperplastic tonsils from 40 children living in Bahia (Brazil) and 40 from German children were analysed for the presence of EBV-encoded small nuclear RNA (EBER) and EBV-encoded proteins by in situ hybridization and immunohistology, respectively. Although the overall EBV infection rate was similar in both groups (50 per cent of Bahian vs. 45 per cent of German cases), a significantly higher number of EBER-positive lymphoid cells were found in the GCs of 8/20 EBV-positive tonsils from Brazil (9-89 cells/GC; mean: 14.5 cells/GC per case), while only 3/18 tonsils from Germany displayed a few EBER positive cells (1-9 cells/GC; mean: 0.5 cell/GC per case) in this compartment (p < 0.007). In addition, the EBV-infected GC cells in Bahian samples resembled centroblasts, exhibited mitotic activity, and in two cases showed expression of EBV-encoded latent membrane protein (LMP)-1, findings not present in German samples. These data show that latently EBV-infected cells participate more frequently in GC reactions in developing regions than in industrialized countries and may abnormally express the oncogenic protein LMP-1. This could in part explain the higher incidence in this region of EBV association with lymphomas related to GC cells or their progeny, such as BL and HD.

Tumor necrosis factor receptor-associated factor 1 is overexpressed in Reed-Sternberg cells of Hodgkin's disease and Epstein-Barr virus-transformed lymphoid cells

The tumor necrosis factor (TNF) receptor-associated factor 1 (TRAF1) is a member of the recently defined TRAF family. It takes part in the signal transduction of the TNF receptor 2 (TNFR2), the lymphotoxin-beta receptor (LT-betaR), CD40, CD30, and LMP1; is induced by LMP1 in vitro; and protects lymphoid cells from apoptosis. To identify the cells in which TRAF1 is active in vivo, we studied TRAF1 transcripts in normal lymphoid tissue, in Epstein-Barr virus (EBV)-induced lymphoproliferations, and in malignant lymphomas with special reference to those that overexpress the cytokine receptor CD30 and CD40 of the TNF receptor family at the single-cell level using a radioactive in situ hybridization. In normal lymphoid tissue, TRAF1 message proved to be absent from all resting B and T cells as well as from macrophages and accessory cells (follicular dendritic cells and interdigitating cells) and present in few perifollicular and intrafollicular lymphoid blasts. In contrast, there was a high and consistent TRAF1 overexpression in EBV-induced lymphoproliferations and Hodgkin's disease. Nearly all non-Hodgkin's lymphoma show low or no TRAF1 expression. Only some cases of diffuse large B-cell lymphoma showed a moderate to high TRAF1 signal. Several of the latter cases were EBV+. These data confirm that TRAF1 is an inducible molecule and indicates its deregulation in the mentioned disorders with the potential of a blockage of the apoptotic pathway.

Increased expression of mRNA for matrix metalloproteinases-1 and -3 and tissue inhibitor of metalloproteinases-1 in intestinal biopsy specimens from patients with coeliac disease

BACKGROUND

Extracellular matrix (ECM) degradation may play a role in villus atrophy in coeliac disease (CD).

AIMS

To compare the cellular expression of mRNA transcripts for the two major matrix degrading proteases, matrix metalloproteinase (MMP)-1 and MMP-3, their inhibitor, tissue inhibitor of metalloproteinases (TIMP)-1, and procollagen I in the intestinal mucosa of patients with untreated and treated CD and normal controls.

PATIENTS/METHODS

Duodenal biopsy specimens from ten untreated CD patients, from six of these after a gluten free diet, and from ten control patients were hybridised with 35S-labelled RNA probes. The number of positive cells in the subepithelial region and lamina propria were counted microscopically.

RESULTS

The numbers of cells positive for MMP-1 (p<0.005), MMP-3 (p<0.01), and TIMP-1 (p<0.05) mRNA were higher in the subepithelial region of CD mucosa than in that from controls. In the lamina propria, only cells positive for MMP-1 mRNA were increased in CD patients compared with controls (p<0.01). MMP-1 and MMP-3 mRNA expression returned to normal in CD patients after treatment with a gluten free diet (p<0.05), while TIMP-1 mRNA expression remained elevated. The number of procollagen I mRNA expressing cells did not change. Expression of MMP-1 and MMP-3 mRNA was mainly localised to subepithelial fibroblasts and macrophages.

CONCLUSIONS

The decreased ratio of collagen I and TIMP-1 mRNA expressing cells to MMP-1 and MMP-3 mRNA expressing cells in untreated CD suggests a shift towards ECM degradation. ECM degradation by activated subepithelial fibroblasts and macrophages may be an important mechanism driving mucosal transformation in CD.

Origin of primary gastric T-cell lymphomas from intraepithelial T-lymphocytes: report of two cases

AIMS

The classification of primary gastric T-cell lymphomas is uncertain due to the exceeding rarity of these tumours; many of the reported cases were felt to be similar to node-based lymphomas. We describe two cases of primary gastric T-cell lymphoma with evidence of origination from intraepithelial T-lymphocytes.

METHODS AND RESULTS

Both tumours were restricted to the stomach; one displaying a large ulcerated mass, the other a widespread superficial tumour manifestation. Histologically the first tumour was composed of sheets of medium-sized lymphoid cells showing marked epitheliotropism at the edge of the ulcer, and a CD3+, CD4-, CD8-, CD20-, CD56-, CD103+, beta F1+ phenotype. The second case differed histologically and immunophenotypically from the first case. In addition to lamina propria and submucosal infiltration, the lymphoma contained an extensive intraepithelial component even in large areas without other evidence of tumour. The neoplastic cells ranged in size from small to medium and large. Immunohistology disclosed a CD3+, CD4+, CD8-, CD20-, CD56-, beta F1+ phenotype. Staining for CD103 could not be performed in this case since frozen material was not available.

CONCLUSIONS

The prominent epitheliotropism, the marked intraepithelial growth and the expression of CD103 strongly imply a derivation of these primary gastric lymphomas from intraepithelial T-lymphocytes. Additional studies of larger series will clarify whether the findings described here are typical of primary gastric T-cell lymphomas.

Lymphoproliferative lesions of the ocular adnexa. Analysis of 112 cases

OBJECTIVE

Lymphoproliferative lesions of the ocular adnexa were analyzed to examine (1) the suitability of the Revised European-American Lymphoma (REAL) classification for the subtyping of the lymphomas in these sites; (2) the predictive value of the REAL classification for the evolution of these tumors; and (3) the frequency and prognostic impact of tumor type, location, proliferation rate (Ki-67 index), p53, CD5 positivity and the presence of monoclonality within these tumors.

DESIGN

Retrospective review.

METHODS

The clinical, histomorphologic, immunohistochemical, and molecular biologic (polymerase chain reaction [PCR]) features of lymphoid proliferations of the ocular adnexa were studied. STUDY MATERIALS: The ocular adnexal lymphoproliferative lesions were located as follows: orbit in 52 patients (46%), conjunctiva in 32 patients (29%), eyelid in 23 patients (21%), and caruncle in 5 patients (4%).

RESULTS

Reactive lymphoid hyperplasia was diagnosed in 12 cases and lymphoma in 99 cases; 1 case remained indeterminate. The five main subtypes of lymphoma according to the REAL classification were extranodal marginal-zone B-cell lymphoma (64%), follicle center lymphoma (10%), diffuse large cell B-cell lymphoma (9%), plasmacytoma (6%), and lymphoplasmocytic lymphoma (5%). Age, gender, and anatomic localization of the lymphomas did not have prognostic significance during a follow-up period of 6 months to 16.5 years (mean, 3.3 years). Extent of disease at time of presentation was the most important clinical prognostic factor: advanced disease correlated with increased risk ratios of having persistent disease at the final follow-up and with lymphoma-related death (P < 0.001). Histomorphologic features and immunohistochemical markers positively correlating with disseminated disease at presentation, stage at final follow-up, and occurrence of lymphoma-related death included cytologic atypia (P < 0.001), MIB-1 proliferation rate (P < 0.001), and tumor cell p53 positivity (P < 0.001). The MIB-1 proliferation rates greater than 20% in extranodal marginal-zone B-cell lymphoma corresponded to at least stage II lymphoma (P < 0.05).

CONCLUSION

The REAL classification is suitable for the subdivision of the ocular adnexal lymphomas. The MIB-1 proliferation rate and p53 positivity may aid the prediction of disease stage and disease progression, whereas PCR can support the diagnosis and reduce the number of histologically indeterminate lesions.

Molecular biology of Hodgkin's disease

The mist surrounding the origin and genesis of HRS cells of classical HD is beginning to dissipate. Molecular biological studies of classical HD at the single cell level strongly suggest that the HRS cells in the majority of cases represent a monoclonal outgrowth of late germinal centre B cells that have lost their capacity to express IG through crippling mutations introduced during the germinal centre reaction. Because of the expression of T cell antigens and/or cytotoxic molecules, the HRS cells of a minority of classical HD cases appear to originate from T cells. Under physiological conditions, B cells that are unable to express IG are eliminated by apoptosis. In most B cell derived classical HD cases, the HRS cells have lost their IG gene coding capacity through mutation and should therefore die of apoptosis. Since this usually does not happen, blockade of the apoptotic pathway may be a major event in the pathogenesis of B cell related classical HD. It is tempting to assume that viruses such as EBV, as well as regulator genes that normally monitor the human genome for damaged DNA, such as TP53, might be involved in the postulated hindrance of the apoptotic pathway, leading to the genesis of classical HRS cells.

Osseous manifestation of Rosai-Dorfman disease (sinus histiocytosis with massive lymphadenopathy). A case report and review of the literature

Rosai-Dorfman disease (sinus histiocytosis with massive lymphadenopathy) is an unusual form of histiocytic disorder. Bone lesions are infrequent. We describe a 33-year-old man with involvement of multiple bones but without lymphadenopathy at the time of presentation. The literature on osseous manifestation in this condition is reviewed.

[Hodgkin's disease: a mystery is being solved]

The cell lineage derivation and type of proliferation (monoclonal versus polyclonal) of the atypical cells in Hodgkin's Disease (HD) has remained in question up until now. Immunophenotypic studies favoured a lymphoid origin. Molecular biological studies using DNA extracted from whole biopsy material provided inconsistent results, probably due to the rarity of the atypical cells in the affected tissue. Hence the molecular biological studies were extended to the analysis of isolated atypical cells. However, even these single cells studies yielded conflicting results. We therefore have improved the technique of single cell isolation from tissue sections and applied it to 25 cases of classical HD and 11 cases of lymphocyte predominant HD (LPHD). We investigated a total of 1,465 single atypical cells for rearranged Ig variable-region chain (V) genes. In all instances in which the single cell DNA lead to a PCR amplification product, these were found to contain identical rearranged V region genes. All of these V region gene sequences proved to be highly mutated. The coding capacity of the rearranged Ig genes was frequently disrupted in classical HD but rarely in LPHD. The V sequences of the latter histotype showed in addition intra-clonal diversity in the majority of patients whereas this was not seen in all but one case of classical HD. Additionally, in 10 to 20% of classical HD cases T-cell antigens and/or cytotoxic molecules could be demonstrated in the atypical cells. These results indicate that, a) the atypical cells of LPHD are a clonal population of neoplastic germinal centre B cells; b) the atypical cells from 80-90% of classical HD cases represent a clonal expansion of B cells which are related to germinal centre B cells or their progeny; and c) the atypical cells of 10-20% of classical HD may originate from T cells.