Loss of HLA-DR expression and immunoblastic morphology predict adverse outcome in diffuse large B-cell lymphoma - analyses of cases from two prospective randomized clinical trials

BACKGROUND

Research on prognostically relevant immunohistochemical markers in diffuse large B-cell lymphomas has mostly been performed on retrospectively collected clinical data. This is also true for immunohistochemical classifiers that are thought to reflect the cell-of-origin subclassification of gene expression studies. In order to obtain deeper insight into the heterogeneous prognosis of diffuse large B-cell lymphomas and to validate a previously published immunohistochemical classifier, we analyzed data from a large set of cases from prospective clinical trials with long-term follow-up.

DESIGN AND METHODS

We performed morphological and extensive immunohistochemical analyses in 414 cases of diffuse large B-cell lymphoma from two prospective randomized clinical trials (NHL-B1/B2, Germany). Classification into germinal center and non-germinal center subtypes of B-cell lymphoma was based on the expression pattern of CD10, BCL6, and IRF4. Multivariate analyses were performed adjusting for the factors in the International Prognostic Index.

RESULTS

Analyzing 20 different epitopes on tissue microarrays, expression of HLA-DR, presence of CD23(+) follicular dendritic cell meshworks, and monotypic light chain expression emerged as International Prognostic Index-independent markers of superior overall survival. Immunoblastic morphology was found to be related to poor event-free survival. The non-germinal center subtype, according to the three-epitope classifier (CD10, BCL6, and IRF4) did not have prognostic relevance when adjusted for International Prognostic Index factors (relative risk=1.2, p=0.328 for overall survival; and relative risk=1.1, p=0.644 for event-free survival).

CONCLUSIONS

The previously reported International Prognostic Index-independent prognostic value of stratification into germinal center/non-germinal center B-cell lymphoma using the expression pattern of CD10, BCL6, and IRF4 was not reproducible in our series. However, other markers and the morphological subtype appear to be of prognostic value.

Girls homozygous for an IL-2-inducible T cell kinase mutation that leads to protein deficiency develop fatal EBV-associated lymphoproliferation

The fatal immune dysregulation that sometimes follows EBV infection in boys has been linked to mutations in two X chromosome-encoded genes, SLAM-associated protein (SAP) and X-linked inhibitor of apoptosis (XIAP). In this study we describe 2 girls from a consanguineous Turkish family who died after developing severe immune dysregulation and therapy-resistant EBV-positive B cell proliferation following EBV infection. SNP array-based genome-wide linkage analysis revealed IL-2-inducible T cell kinase (ITK) as a candidate gene for this immunodeficiency syndrome. Both girls harbored a homozygous missense mutation that led to substitution of a highly conserved residue (R335W) in the SH2 domain of ITK. Characteristics of ITK deficiency in mouse models, such as absence of NKT cells and high levels of eomesodermin in CD8+ cells, were seen in either one or both of the girls. Two lines of evidence suggested that R335W caused instability of the ITK protein. First, in silico modeling of the mutant protein predicted destabilization of the SH2 domain. Additionally, Western blot analysis revealed that, unlike wild-type ITK, the R335W mutant was nearly undetectable when expressed in 293 T cells. Our results suggest that ITK deficiency causes what we believe to be a novel immunodeficiency syndrome that leads to a fatal inadequate immune response to EBV. Because ITK deficiency resembles EBV-associated lymphoproliferative disorders in boys, we suggest that this molecular cause should be considered during diagnosis and treatment.

Expression profiling reveals specific gene expression signatures in gastric MALT lymphomas

The purpose of this study is to identify genes that are involved in the etiology of Helicobacter pylori induced gastric MALT lymphoma. We compared gene expression profiles of gastric MALT lymphoma with their corresponding gastric MALT (chronic gastritis with formation of follicles and aggregates). cDNA microarrays were used to compare these two tissue types from the same patient (n = 21). Quantitative PCR and immunohistochemical staining were performed to validate the microarray results. Three hundred and fifty eight out of 11,552 genes were differentially expressed between gastric MALT lymphomas and gastric MALT. Thirty eight genes are implicated in immune response, 66 in signal transduction and 36 in cell proliferation. Interestingly, chromosome 6 was the only chromosome which was significantly over-represented with 25 genes (EASE score p = 0.01254). Several surface markers of haematopoietic cells, such as CD1c, CD40, CD44, CD53, CD83, CD86 and members of the HLA-D family were up-regulated in lymphoma tissues, indicating antigen-dependent survival of lymphoma cells. We conclude that gastric MALT lymphoma shows a specific gene expression profile, which allows the differentiation from H. pylori induced lymphoid gastritis.

Tumor sclerosis but not cell proliferation or malignancy grade is a prognostic marker in advanced-stage follicular lymphoma: the German Low Grade Lymphoma Study Group

PURPOSE

Follicular lymphoma is an indolent lymphoma with a long median overall survival. However, a considerable number of patients die within the first 2 years after the onset of the disease. Because the treatment options vary with respect to antitumor effect and potential toxic adverse effects, the identification of high-risk patients would be helpful in directing therapeutic decisions in individual patients. Several histopathologic biomarkers for risk stratification have been suggested, but most markers have not been validated in patients treated in prospective trials.

PATIENTS AND METHODS

We report a comprehensive approach to evaluate histopathologic biomarkers, including WHO grade, histology, and proliferation and quantitation of immune bystander cells, in 158 patients with nodal advanced-stage follicular lymphoma treated first line within a randomized trial.

RESULTS

Tumor sclerosis was a significant prognostic marker of poor overall survival that was independent of the Follicular Lymphoma International Prognostic Index (FLIPI). WHO grade, proliferation, and total T-cell or macrophage content were not associated with overall survival.

CONCLUSION

The presence of sclerosis within the lymphoma is a marker of poor overall survival that is independent of the FLIPI. The quantification of macrophage or absolute T-cell content, grading, and proliferation are of no help in predicting the outcome of FL. Future studies need to identify surrogate markers for the prognostic immune signatures identified by gene expression profiling. Most importantly, new prognostic markers need to be confirmed in patients treated within prospective trials.

Prevalence, clinical pattern, and outcome of CNS involvement in childhood and adolescent non-Hodgkin's lymphoma differ by non-Hodgkin's lymphoma subtype: a Berlin-Frankfurt-Munster Group Report

PURPOSE

We analyzed the prevalence, clinical pattern, and prognostic impact of CNS involvement in a large cohort of children and adolescents diagnosed with non-Hodgkin's lymphoma (NHL), with special attention to differences according to NHL subtype.

PATIENTS AND METHODS

From October 1986 to December 2002, 2,381 patients (median age, 9.37 years; range, 0.2 to 23.8 years; female-to-male ratio, 1:2.7) from Germany, Austria, and Switzerland were registered. A total of 2,086 patients were eligible for the consecutive multicenter protocols NHL-Berlin-Frankfurt-Münster [BFM] -86, NHL-BFM-90, and NHL-BFM-95, and could be evaluated for outcome.

RESULTS

CNS involvement was diagnosed in 141 (5.9%) of 2,381 patients and was associated with an advanced stage of NHL. The percentage of CNS-positive patients was 8.8% for Burkitt's lymphoma/Burkitt's leukemia (BL/B-ALL), 5.4% for precursor B-lymphoblastic lymphoma (pB-LBL), 3.3% for anaplastic large-cell lymphoma, 3.2% for T-cell-LBL, 2.6% for diffuse large B-cell lymphoma, and 0% for primary mediastinal large B-cell NHL (P < .001). Most CNS-positive patients with pB-LBL, T-LBL, or BL/B-ALL had meningeal disease. The probability of event-free survival (pEFS; +/- SE) at 5 years was 85% +/- 1% for the 2,086 protocol patients (median follow-up, 6.5 years; range, 0.3 to 17.7 years). For the 112 CNS-positive patients, pEFS was 64% +/- 5%, compared with 86% +/- 1% for the 1,927 CNS-negative patients (P < .001). Although CNS disease had no impact on pEFS for advanced-stage T-LBL patients, CNS-positive patients with BL/B-ALL had a worse average outcome than CNS-negative patients with stage IV BL/B-ALL (60% +/- 5% v 81% +/- 3%; P < .001). In multivariate analysis, CNS disease was the strongest predictor for relapse in BL/B-ALL patients with advanced-stage disease.

CONCLUSION

Six percent of childhood/adolescent NHL patients were CNS positive. However, the prevalence, pattern, and prognostic impact of CNS involvement differed among NHL subtypes.

Follikuläre Lymphome und Mantelzelllymphome

Indolent (low-grade) B-cell non-Hodgkin's lymphomas, such as follicular and mantle cell lymphomas, are primarily nodal lymphomas in which lymph node involvement is the dominant clinical feature. The frequency of extranodal manifestations of these primarily nodal lymphomas is often underestimated. The typical growth pattern of nodal lymphomas can be absent or not evaluable because the biopsy specimens are often small in cases with extranodal involvement. Therefore, the immunophenotype of the lymphoma cells is of great importance for the diagnosis of indolent lymphomas with extranodal localizations.

A biologic definition of Burkitt's lymphoma from transcriptional and genomic profiling

BACKGROUND

The distinction between Burkitt's lymphoma and diffuse large-B-cell lymphoma is unclear. We used transcriptional and genomic profiling to define Burkitt's lymphoma more precisely and to distinguish subgroups in other types of mature aggressive B-cell lymphomas.

METHODS

We performed gene-expression profiling using Affymetrix U133A GeneChips with RNA from 220 mature aggressive B-cell lymphomas, including a core group of 8 Burkitt's lymphomas that met all World Health Organization (WHO) criteria. A molecular signature for Burkitt's lymphoma was generated, and chromosomal abnormalities were detected with interphase fluorescence in situ hybridization and array-based comparative genomic hybridization.

RESULTS

We used the molecular signature for Burkitt's lymphoma to identify 44 cases: 11 had the morphologic features of diffuse large-B-cell lymphomas, 4 were unclassifiable mature aggressive B-cell lymphomas, and 29 had a classic or atypical Burkitt's morphologic appearance. Also, five did not have a detectable IG-myc Burkitt's translocation, whereas the others contained an IG-myc fusion, mostly in simple karyotypes. Of the 176 lymphomas without the molecular signature for Burkitt's lymphoma, 155 were diffuse large-B-cell lymphomas. Of these 155 cases, 21 percent had a chromosomal breakpoint at the myc locus associated with complex chromosomal changes and an unfavorable clinical course.

CONCLUSIONS

Our molecular definition of Burkitt's lymphoma clarifies and extends the spectrum of the WHO criteria for Burkitt's lymphoma. In mature aggressive B-cell lymphomas without a gene signature for Burkitt's lymphoma, chromosomal breakpoints at the myc locus were associated with an adverse clinical outcome.

Diffuse large B-cell lymphoma in pediatric patients belongs predominantly to the germinal-center type B-cell lymphomas: a clinicopathologic analysis of cases included in the German BFM (Berlin-Frankfurt-Münster) Multicenter Trial

Diffuse large B-cell lymphoma (DLBCL) in adults is a heterogeneous disease. Biologic subgroups of DLBCL with a favorable prognosis (germinal center B-cell–like, GCB) and with a poor prognosis (activated B-cell–like, ABC) have been defined by gene expression profiling and can be distinguished by immunohistochemistry. In contrast to their adult counterparts, children with DLBCL have an excellent prognosis. We analyzed 63 cases of DLBCL in pediatric patients by immunohistochemistry and fluorescence in situ hybridization (FISH) and found a striking predominance of a GCB subtype, which might explain the good clinical outcome in these lymphomas. Interestingly, FISH applied to 50 of these cases, as well as conventional cytogenetics available in 3 cases, revealed absence of the translocation t(14;18) involving the BCL2 gene, which is present in about 15% of adult GCB subtype DLBCL. Our data indicate that pediatric DLBCL differs from adult DLBCL and might comprise a biologically unique subgroup of DLBCL from which important insights into the pathogenesis and biology of this disease might be gained.

Lymphomas of the female genital tract: a study of 186 cases and review of the literature

Malignant lymphomas in the female genital tract are rare, and those arising from this tissue system are extremely uncommon. Most pertinent reports lack clear references to the accepted classifications or failed to apply immunomarkers and molecular techniques for a reliable diagnosis. We analyzed a large group of patients with primary and secondary lymphomas of the female genital tract classified on the basis of the recent WHO consensus. A total of 186 patients with malignant lymphoma detected in the female genital tract were selected from the files of the Kiel Lymphoma Registry covering the period of 1974 to 2004. Stringent criteria were applied to separate systemic versus secondary lymphomas. All cases were reviewed on the basis of conventionally stained sections, relevant immunohistochemistry using the alkaline phosphatase/anti-alkaline phosphatase technique, and clinical information, as far as available. When required, gene rearrangement analysis was performed, including TCR-gamma chain gene and the three FR fragments of the IgG heavy chain gene. In addition, typical chromosomal translocations were detected by means of the FISH technique to verify the diagnosis, where needed. Thirty-seven percent of the cases were systemic lymphomas and 63% were mostly extranodal lymphomas primary to the female genital tract. The adnexa were involved in 87 cases, followed by uterine corpus in 23 cases, uterine cervix in 17 cases, portio in 9 cases, vagina in 11 cases, and vulva including clitoris in 8 cases. In 31 cases, two or more adjacent sites were involved. In both (primary and secondary) groups, the adnexa were the prevailing site of involvement. As expected, the overwhelming majority of cases were of B phenotype. The most frequent type of lymphoma proved to be diffuse large B-cell lymphoma, closely followed by follicular lymphoma, including all 3 grades of malignancy. Burkitt lymphoma showed a rather similar frequency. Marginal zone lymphoma occurred exclusively as primary lesions in the uterine mucosa. Lymphoplasmacytic lymphoma was restricted to the vulvo-vaginal area and occurred in women over 60 years of age. In conclusion, our study provides a thorough overview of various types of lymphoma affecting the female genital tract primarily or secondarily, which were classified on the basis of a widely accepted WHO classification. Although quite rare, our report should remind the pathologist of considering malignant lymphomas while reading biopsies taken from female genital organ.

Long-Term Survival Following Radiotherapy and Cytarabine Chemotherapy for Sporadic Primary Central Nervous System Lymphoma

PURPOSE

To analyze the long-term results following whole brain radiotherapy (WBRT) with sequential intrathecal (i.th.) cytosine arabinoside (Ara-C) +/- intravenous (i.v.) Ara-C in patients with primary central nervous system lymphoma (PCNSL).

PATIENTS AND METHODS

14 patients were treated between July 1987 and August 1995. All had sporadic PCNSL with proven histology of high-grade CNS lymphoma (twelve diffuse large-cell B-lymphomas, one lymphoblastic lymphoma, one large T-cell lymphoma). Patients were treated with two to four cycles of induction chemotherapy (40 mg/m2 Ara-C i.th.), four patients received additional Ara-C i.v. (150 mg/m2, d1-4). WBRT was administered using 1.8-Gy fractions. Intrathecal chemotherapy was planned afterwards in 4-week intervals for 6 months. Posttreatment neurocognitive evaluations were performed in two long-term survivors.

RESULTS

Two of four patients who received i.v. and i.th. induction chemotherapy showed progressive disease, and irradiation was started immediately. Six of 14 patients received 50.4 Gy WBRT, four patients had WBRT up to 39.6 Gy followed by a 10.8-Gy boost. Five patients died early during therapy either due to a decline of the general medical condition or progressive disease. Median survival was 41 months (95% confidence interval: 6-79 months), survival at 3 and 5 years was 59% and 42%, respectively. Six patients survived for 3 years, two younger patients are still alive (> 12 years). They show only slightly impaired neurocognitive functions without clinical relevance.

CONCLUSION

This WBRT-based protocol with i.th. meningeal prophylaxis using Ara-C +/- i.v. Ara-C yields substantial long-term survival with moderate toxicity. The value of i.v. chemotherapy is currently being investigated in prospective studies.

Typing the histogenetic origin of the tumor cells of lymphocyte-rich classical Hodgkin's lymphoma in relation to tumor cells of classical and lymphocyte-predominance Hodgkin's lymphoma

Hodgkin's lymphoma (HL) is separated into the classical (c) and lymphocyte-predominance (lp) forms. Whereas classical Hodgkin-Reed/Sternberg (HRS) cells carry mutated immunoglobulin (Ig) gene rearrangements that are often "crippled" and lack intraclonal diversity, and are likely derived from preapoptotic germinal center (GC) B cells, the lymphocytic and histiocytic cells of lpHL are presumably derived from selected GC B cells and often show ongoing somatic hypermutation. The recently identified lymphocyte-rich classical (lrc) HL is characterized by HRS cells with the immunophenotype of classical HRS cells (CD30(+)CD15(+)CD20(-)CD45(-)) but an infiltrate similar to lpHL and a clinical behavior resembling lpHL. To identify the histogenetic origin of the HRS cells in lrcHL and to determine the relationship to the lymphoma cells of cHL and lpHL we characterized seven cases of lrcHL by immunohistochemistry and sequenced the rearranged Ig genes of single micromanipulated HRS cells. The expression patterns of BCL6, CD138, Oct2, and BOB1 in HRS cells of lrcHL showed differences to those of both cHL and lpHL. Analyses of rearranged Ig genes identified clonal HRS cell expansions carrying mutated Ig rearrangements without significant intraclonal diversity in all seven of the cases. In two cases crippling mutations, rendering originally functional V gene rearrangements nonfunctional, were observed. Thus, the mutation pattern of rearranged Ig genes of HRS cells in lrcHL is clearly different from those in lymphocytic and histiocytic cells of lpHL, and resembles the pattern in HRS cells of cHL, suggesting that HRS cells in lrcHL derive from (preapoptotic) GC B cells that silenced hypermutation. In one case in addition to the dominant HRS cell clone, CD30(+) EBV-infected HRS-like cells unrelated to the tumor clone were observed, suggesting development of an expanded population of EBV-harboring HRS-like cells in the microenvironment of HL.

Differential expression of cancer testis genes in histological subtypes of non-Hodgkin's lymphomas

PURPOSE

The purpose of this study was to determine the potentialof cancer testis (CT) antigens as vaccines for non-Hodgkin's lymphomas (NHLs).

EXPERIMENTAL DESIGN

Ninety-three specimens of NHLs were analyzed for their composite expression of eight CT genes (MAGE-3, MAGE-4, CT-7, HOM-MEL-40/SSX-2, SSX-1, SSX-4, HOM-TES-14/SCP-1, and HOM-TES-85). Thirty-nine of these specimens were also analyzed for their NY-ESO-1 expression.

RESULTS

Only 1 of 7 cases of chronic lymphocytic leukemia expressed a CT gene (HOM-TES-14/SCP-1), and 10 follicular lymphomas were negative for all of the CT genes tested. In B-cell lymphomas, the most frequent expression of CT genes was observed in diffuse large-cell lymphomas (HOM-TES-14/SCP-1: 7 of 28; SSX-1: 5 of 28; CT-7: 2 of 28; and HOM-MEL-40/SSX-2 and HOM-TES-85: 1 of 28 positive cases). Only 1 of 8 Burkitt's and 1 of 7 lymphoblastic lymphomas expressed a CT gene (CT7 and HOM-TES-14/SCP-1, respectively). A majority (9 of 15) of T- NHLs (9 peripheral T-cell lymphomas, 2 lymphoblastic T-cell lymphomas, and 4 cases of AILD) expressed HOM-TES-14/SCP-1.

CONCLUSIONS

HOM-TES-14/SCP-1, and to some degree SSX-1 and CT-7 might be candidates for lymphoma vaccine development. However, the identification of additional tumor-specific antigens with a frequent expression in lymphomas is warranted to allow for the development of widely applicable polyvalent lymphoma vaccines.

Cloning of a complementary DNA encoding the unique dendritic cell antigen Ki-M9

Human sinus-lining cells (SLC) of the lymph node sinuses most probably represent accessory cells for the primary humoral immune response and have been shown to express a unique antigen recognized by the monoclonal antibody Ki-M9. To characterize this SLC-specific antigen further, a spleen cDNA library established in the expression vector lambda gt-11 was searched immunochemically for clones expressing the Ki-M9 antigen. Two recombinant phage clones revealed a cDNA with an open reading frame of 1666 bp encoding a 68-kDa protein. When fused with an expression vector that codes for the bacterial maltose-binding protein (MBP), the purified MBP-Ki-M9 fusion protein could be clearly detected by Western blot analysis. Furthermore, in situ hybridization with Ki-M9 cDNA as a probe confirmed the SLC-specific expression of the cloned cDNA. Additionally, Ki-M9 mRNA transcripts were detected in follicular dendritic reticulum cells of the secondary germinal centers, in a few cells of the perifollicular zone of the spleen, in some sinusoidal cells of liver, and in thymic reticular cells. A sequence database research revealed a strong homology to a murine cDNA. By applying non-radioactive in situ hybridization on mouse tissue, strong expression in SLC of the lymph node and metallophilic cells of the spleen in mouse tissue could be seen indicating that the Ki-M9 cDNA is highly conserved in the two species. Further computer analysis of the deduced amino acid sequence of the Ki-M9 antigen showed a large number of potential glycosylation sites and a PEST motive, which are characteristic for rapidly degraded membrane bound proteins and represent prerequisites for the function of this cell system in initiating the humoral immune response.

Reduced T-cell receptor CD3zeta-chain protein and sustained CD3epsilon expression at the site of mycobacterial infection

Control of mycobacterial infection by the cellular immune system relies both on antigen-presenting cells and on T lymphocytes. The quality of an effective cellular immune response is dependent on functional signal transduction residing in the cytoplasmic tails of the T-cell receptor CD3 components. In order to investigate potential effects of mycobacteria on T-cell receptor signalling, we examined the protein expression of T-cell signal transduction molecules (CD3zeta, ZAP-70, p59fyn, p56lck). In Western blots of peripheral blood mononuclear cells of Mycobacterium tuberculosis infected patients, only the CD3zeta-chain showed a marked reduction in protein expression. To investigate the situation in situ, immunoenzymatic and immunofluorescence stainings for CD3epsilon and CD3zeta expression were performed on sections of normal lymphoid tissue, M. leprae infected and sarcoid tissue. CD3epsilon and CD3zeta expression were similar with respect to intensity, localization and the number of cells stained in normal lymphoid tissue and in sarcoid granulomas. In contrast, the granulomas of M. leprae infected tissues showed a significantly reduced expression of CD3zeta compared to CD3epsilon. Using double immunofluorescence analysis, virtually no CD3zeta expression could be detected in comparison to the CD3epsilon expression in the lesions. Apparently, mycobacteria are capable of significantly reducing CD3zeta-chain expression, which may be restored by cytokines. IL-2-enhanced zeta-chain expression and T-cell effector functions, defined by interferon-gamma release, in M. tuberculosis-specific and human leucocyte antigen-DR restricted CD4+ T cells isolated from granuloma lesions from patients with pulmonary tuberculosis. Because CD3zeta is essential for CD3 signalling and for eliciting T-cell effector functions, reduced CD3zeta protein expression could result in altered signal transduction and inefficient T-cell effector functions. Alternatively, reduced CD3zeta-chain expression may protect T cells from repetitive TCR stimulation associated with anergy or apoptosis.

Survival and clonal expansion of mutating "forbidden" (immunoglobulin receptor-deficient) epstein-barr virus-infected b cells in angioimmunoblastic t cell lymphoma

Angioimmunoblastic lymphadenopathy with dysproteinemia (AILD) is a peculiar T cell lymphoma, as expanding B cell clones are often present besides the malignant T cell clones. In addition, large numbers of Epstein-Barr virus (EBV)-infected B cells are frequently observed. To analyze the differentiation status and clonal composition of EBV-harboring B cells in AILD, single EBV-infected cells were micromanipulated from lymph nodes of six patients with frequent EBV(+) cells and their rearranged immunoglobulin (Ig) genes analyzed. Most EBV-infected B cells carried mutated Ig genes, indicating that in AILD, EBV preferentially resides in memory and/or germinal center B cells. EBV(+) B cell clones observed in all six cases ranged from small polyclonal to large monoclonal expansions and often showed ongoing somatic hypermutation while EBV(-) B cells showed little tendency for clonal expansion. Surprisingly, many members of expanding B cell clones had acquired destructive mutations in originally functional V gene rearrangements and showed an unfavorable high load of replacement mutations in the framework regions, indicating that they accumulated mutations over repeated rounds of mutation and division while not being selected through their antigen receptor. This sustained selection-free accumulation of somatic mutations is unique to AILD. Moreover, the survival and clonal expansion of "forbidden" (i.e., Ig-deficient) B cells has not been observed before in vivo and thus represents a novel type of viral latency in the B cell compartment. It is likely the interplay between the microenvironment in AILD lymph nodes and the viral transformation that leads to the survival and clonal expansion of Ig-less B cells.

Analysis of T-cell subpopulations in T-cell non-Hodgkin's lymphoma of angioimmunoblastic lymphadenopathy with dysproteinemia type by single target gene amplification of T cell receptor- beta gene rearrangements

Angioimmunoblastic lymphadenopathy with dysproteinemia (AILD) is defined in the current lymphoma classifications as a T-cell non-Hodgkin's lymphoma. However, in approximately one third of the cases of this lymphoproliferative disease rearrangements of T-cell receptor (TCR) genes indicating clonal expansion of T cells are not detectable. It is currently believed that these cases may represent early stages of a lymphoma with a minor oligoclonal T-cell population. In the present study, 18 lymph nodes with the characteristic histology of AILD were investigated for clonal T-cell receptor gene rearrangements by analysis of DNA extracted from whole tissue sections. Dominant T-cell clones were detected in 12 of these cases. Single CD4(+) and CD8(+) T cells and proliferating Ki67(+) cells of seven cases were micromanipulated from frozen tissue sections. TCRbeta gene rearrangements were amplified from these cells by polymerase chain reaction and sequenced. In all informative cases, the clonal gene rearrangements were only detected among CD4(+), and not among CD8(+) T cells, indicating that the tumor clones in AILD usually derive from CD4(+) T cells. Minor clonal T-cell populations in those cases in which no clone was found by whole-tissue DNA analysis were not detectable even at single cell resolution. T-cell clones in 4 of 10 cases were found to express similar TCRbeta chains, indicating a potential role of (super) antigen triggering in at least some cases of AILD.

B-cell development in progressively transformed germinal centers: similarities and differences compared with classical germinal centers and lymphocyte-predominant Hodgkin disease

Progressively transformed germinal centers (PTGCs) are histologic structures mainly composed of small resting B cells and intermingled proliferating centroblast-like cells. The B-cell differentiation processes within PTGCs and their relation to classical germinal centers (GC) and to lymphocyte-predominant Hodgkin disease (LPHD), with which PTGCs are often associated, are largely unknown. To address these issues, single small resting (Ki67-) and proliferating (Ki67+) centroblast-like cells were isolated from 7 PTGCs of 5 lymph nodes, and rearranged immunoglobulin genes were amplified and sequenced. Most small resting B cells were clonally unrelated, and most carried unmutated immunoglobulin gene rearrangements resembling mantle zone B cells. Small resting B cells with mutated immunoglobulin gene rearrangements may represent centrocytes, memory B cells, or both. Among the centroblast-like Ki67+ cells, expanded B-cell clones were observed in 6 of 7 PTGCs analyzed. Clonally related V region genes showed extensive intraclonal diversity, and the mutation pattern indicated stringent selection of the cells for the expression of functional antigen receptors. Thus, somatic hypermutation, clonal expansion, and selection occur also in the disorganized PTGC microenvironment, as in classical GCs. In lymph nodes affected by PTGCs, no clonal expansion across the borders of individual PTGCs was observed, distinguishing PTGCs from LPHD.

Primary adenosquamous and squamous cell carcinoma of the upper urinary tract. Report on three cases

Three cases of adenosquamous cell carcinoma and squamous cell carcinoma of the upper urinary tract are presented. The fact that the urothelium normally has no glandular or squamous structures renders the pathogenesis of these tumours interesting. The process is assumed to begin with an urothelial metaplasia resulting from a reaction to chronic irritation, leading to dedifferentiation, dysplasias and, in the end, to a squamous cell carcinoma or adenocarcinoma. The relevant medical histories include chronic episodes of pyelonephritis or nephrolithiasis. Diagnosis, therapeutic approaches and prognosis of these rare tumours are discussed.

Hodgkin and Reed-Sternberg-like cells in B-cell chronic lymphocytic leukemia represent the outgrowth of single germinal-center B-cell-derived clones: potential precursors of Hodgkin and Reed-Sternberg cells in Hodgkin's disease

In rare cases of B-cell chronic lymphocytic leukemia (B-CLL), large cells morphologically similar to or indistinguishable from Hodgkin/Reed-Sternberg (HRS) cells of Hodgkin's disease (HD) can be found in a background of otherwise typical B-CLL. To test these HRS-like cells for a potential clonal relationship to the B-CLL cells, single cells were micromanipulated from immunostained tissue sections, and rearranged immunoglobulin genes were amplified from HRS-like cells and B-CLL cells and sequenced. The same variable (V) gene rearrangements with shared and distinct somatic mutations were found in HRS-like and B-CLL cells from 1 patient, which indicates derivation of these cells from 2 distinct members of a germinal-center B-cell clone. Separate clonal V gene rearrangements were amplified from HRS-like and B-CLL cells from 2 other patients, showing concomitant presence of 2 distinct expanded B-cell clones. Epstein-Barr virus (EBV) was detected in the HRS-like cells of these 2 latter cases, indicating clonal expansion of an EBV-harboring B cell in the setting of B-CLL. There is evidence that HRS-like cells in B-CLL, like HRS cells in HD, derive from germinal-center B cells. In all cases, somatic mutations have been detected in the rearranged V genes of the HRS-like cells, and in 1 of the EBV-positive HRS-like cell clones, somatic mutations rendered an originally functional V gene rearrangement nonfunctional. We speculate that the HRS-like cells in B-CLL represent potential precursors for HRS cells causing HD.

Hodgkin and Reed-Sternberg cells in lymphocyte predominant Hodgkin disease represent clonal populations of germinal center-derived tumor B cells

Among the four subtypes of Hodgkin disease (HD), lymphocyte-predominant (LP) HD is now generally considered as a separate entity. The B cell nature of the typical Hodgkin and Reed-Sternberg (HRS) cells and their variants (L and H, lymphocytic and histiocytic cells) in LP HD has long been suspected, but the question of whether these cells represent a true tumor clone is unclear. We previously demonstrated clonal Ig gene rearrangements in one case of LP HD. In the present study, five cases of LP HD were analyzed by micromanipulation of single HRS cells from frozen tissue sections and DNA amplification of rearranged Ig heavy chain genes from those cells. Clonal V gene rearrangements harboring somatic mutations were detected in each case. In three cases ongoing somatic mutation was evident. This shows that HRS cells in LP HD are a clonal tumor population derived from germinal center B cells. The pattern of somatic mutation indicates that HRS cells in LP HD are selected for antibody expression. This, and the presence of ongoing mutation discriminates LP from classical HD.

Sinus-lining cells of the lymph nodes recognized as a dendritic cell type by the new monoclonal antibody Ki-M9

In the immunobiological characterization of lymph node cells, sinus-lining cells (SLCs) have been given little attention mainly due to the difficulties in their recognition. Ki-M9 is a new monoclonal antibody (MAb) selected for its unique capability to visualize SLCs in human lymph nodes. The details were established by light and electron microscopy and immunoprecipitation of the corresponding biosynthetically labeled antigen. Ki-M9 recognizes a 70-kd protein localized on the surface membrane of SLCs. In the lymphoid tissue, a mild reactivity was exclusively encountered on follicular dendritic reticulum cells in the germinal centers of secondary lymphoid follicles. In other organs, some squamous epithelial and myoepithelial cells were recognized by this antibody. Immunomonitoring of SLCs on light and electron microscopic levels revealed their dendritic morphology, lack of phagosomes, and their close association with type IV collagen fibers. Considering the occurrence of typical dendritic SLCs on the front line of antigen flood, we propose that SLCs be investigated for a possible antigen-binding property.

p100: a novel proliferation-associated nuclear protein specifically restricted to cell cycle phases S, G2, and M

By immunization with nuclear lysates of L428 cells, we raised a monoclonal mouse antibody, Ki-S2 (IgG1). In Western blots, this antibody recognizes a nuclear antigen with an apparent molecular mass of 100 kD, termed p100. Protein sequencing of p100 showed that this is a hitherto unknown protein. Immunohistochemical examination of cryostat and paraffin sections of nearly all human tissue types and neoplasms showed that p100 was exclusively expressed in the nuclei of a fraction of proliferating cells. Cell sorting and fluorescence-activated cell sorting analysis of stimulated peripheral blood mononuclear cells showed that p100 was exclusively expressed in proliferating cells from the transition G1/S until the end of cytokinesis. During mitosis, this protein is strictly associated with the spindle pole and with the mitotic spindle, whereas during S and G2, p100 is diffusely distributed throughout the cell nucleus. Immediately after completion of cytokinesis, p100 was rapidly degraded. In L428 cells, p100 is phosphorylated at least during mitosis. It has a turnover time of about 1 hour. Studies on routinely processed paraffin sections of specimens of malignant lymphoma, benign and malignant nevocellular tumors, and breast cancer showed that in all cases less than 40% of the Ki-67-positive growth fraction expressed p100. Thus, p100 might prove to be a more reliable measure of cellular proliferation and one that is more closely correlated to cancer prognosis, beyond its general biologic relevance as a cell cycle protein.

Immunophenotyping of dermal spindle cell tumors: diagnostic value of monocyte marker Ki-M1p and histogenetic considerations

Various studies have reported the utility of anti-CD34 staining in the differential diagnosis of dermal spindle-cell tumors. To investigate whether monoclonal antibody Ki-M1p might add practical diagnostic information, we examined a total of 120 cutaneous spindle cell neoplasms using a panel of markers. Anti-CD34 antibody QBEnd/10 consistently stained dermatofibrosarcomas, Kaposi's sarcomas, neurofibromas, and, to a lesser extent, hemangiopericytomas. A positive reaction was also found in > 18% of the dermatofibromas. Ki-M1p staining showed an intense immunoreaction in all dermatofibromas, whereas no reactivity was observed in dermatofibrosarcomas. In addition, a subset of cells was labeled in atypical fibroxanthomas and Kaposi's sarcomas. Neurofibromas, spindle-cell hemangioendotheliomas, and hemangiopericytomas were negative. Dermatofibrosarcomas and atypical fibroxanthomas also moderately expressed smooth muscle-specific actin. Immunohistochemically, a discrimination between dermatofibrosarcomas and neurofibromas was possible only by means of an antibody against the nerve growth factor receptor. We conclude that the combination of several antibodies, in particular anti-CD34 and Ki-M1p, may improve the accuracy of diagnostic immunohistochemistry in the field of cutaneous spindle cell tumors. We speculate that dermatofibroma is primarily a macrophage-rich inflammatory lesion in which cytokine secretion induces a secondary proliferation of fibroblasts, whereas dermatofibrosarcoma is likely to issue from primitive dermal cells of uncertain origin.

Detection of rare RNA sequences by single-enzyme in situ reverse transcription-polymerase chain reaction. High-resolution analyses of interleukin-6 mRNA in paraffin sections of lymph nodes

To study the distribution pattern of interleukin-6 (IL-6)-producing cells in normal human lymph nodes, we applied the in situ reverse transcription-polymerase chain reaction technique. We describe a new modification of this technique for monitoring small amounts of specific nucleotide sequences in conventional paraffin sections. This technique differs in at least two respects from those described earlier. The two decisive steps are: 1) the reverse transcription of mRNA and the subsequent amplification of cDNA by polymerase chain reaction are performed by a new single enzyme capable of both reaction types in one and the same medium without buffer exchange; and 2) for the specific detection of the amplified cDNA, a modified version of the primed in situ labeling technique was used. The technique, carried out on normal human lymph nodes, traces a low load of IL-6 mRNA in fibroblasts, endothelial cells, and a minor population of T lymphocytes in the pulp region. High levels of expression were encountered in about 20% of perisinusoidal pulp macrophages. In addition, moderate activity was detectable in sinus lining cells. Because no major activity was found in the germinal centers of the lymphoid B follicles and in the T zone, it is suggested that the plasma cell differentiation ensuing from primary and secondary B-cell immunization is mainly effected by the sinus lining cells as well as perifollicular and perisinusoidal pulp macrophages capable of producing high amounts of IL-6.

Detection of human topoisomerase II alpha in cell lines and tissues: characterization of five novel monoclonal antibodies

We report five novel monoclonal antibodies (Ki-S1, Ki-S4, Ki-S6, Ki-S7, and Ki-S8) reactive with a proliferation-related nuclear antigen. In immunoprecipitation and Western blot experiments using crude nuclear extracts, they recognized a protein of 170 kD that, after proteolytic digestion of the immunoprecipitate and sequencing of the resulting peptides, was identified as the alpha-isoform of human topoisomerase II. This was confirmed by testing the antibodies on a highly purified enzyme preparation. Crossreactivity with topoisomerase II beta was ruled out by testing the antibodies on crude extracts from yeast cells expressing the beta-isoform exclusively. The antibodies bind the antigen with different affinities and at different epitopes, apparently located within the carboxyl third of the enzyme. All five antibodies are suitable for archival material after adequate antigen retrieval, thereby enabling retrospective studies. This report illustrates the tissue and subcellular distribution of the antigen through the cell cycle by immunohistochemistry and confocal fluorescence microscopy. The antibodies will be useful tools in further analysis of morphological and functional aspects of topoisomerase II and may serve diagnostic purposes, as well as providing prognostic information in tumor pathology.

Correlation between DNA ploidy, proliferation marker Ki-67 and early tumor progression in renal cell carcinoma. A prospective study

OBJECTIVE

The course of metastatic renal cell carcinoma shows a broad range of interindividual variation that cannot be sufficiently predicted by tumor stage and grade. The aim of this study was to establish the prognostic value of DNA ploidy and the proliferation marker Ki-67 in renal cell carcinoma.

METHODS

Both parameters were measured simultaneously in 100 tumors and then correlated with the classic prognostic criteria pathologic stage and tumor differentiation grade as well as clinical course (early tumor progression).

RESULTS

DNA ploidy correlated well with staging, grading and early progression. The proliferation index (Ki-67) correlated well with tumor stage and histopathological grade but not with the clinical course (early progression).

CONCLUSION

Due to the diverse biological potential of renal cell carcinoma observation of further clinical course, including late tumor progression, will be necessary to determine whether one of these two indicators can provide additional information beyond what differentiation grade and tumor stage already tell us.

Migration and activation pattern of specialized dendritic cells after heterotopic small bowel transplantation in a graft-versus-host model of the rat

Besides specific cellular-mediated T cell responses, B cell related humoral responses have been demonstrated during the course of graft-versus-host disease after semiallogeneic transplantation of cellular antigen. Following semiallogeneic small bowel transplantation, there are, besides others, two specific forms of antigen-presenting cells, namely sinus lining cells (SLCs) and follicular dendritic cells (FDCs) which mediate primary and secondary humoral immune responses, respectively. This study was aimed to clarify the role of these dendritic cell entities after transplantation of small bowel grafts in a one-sided graft-versus-host (GvH) model for untreated and immunosuppressed (15-deoxyspergualin) recipient animals. As graft-versus-host disease progressed, SLCs and FDCs were eliminated in donor and recipient graft-versus-host associated target tissues (spleen and mesenteric lymph nodes) of untreated animals, whereas these dendritic cells prevailed in immunosuppressed recipients. 15-deoxyspergualin successfully prevented GvHD and significantly prolonged the mean survival time of untreated rats (16.0 +/- 4.5 d) for at least 21 d. Based on the immunosuppressive efficacy of 15-deoxyspergualin on the survival and function of SLCs and FDCs, an unaltered development of germinal centers and B cell proliferation within mesenteric lymph nodes and spleen was maintained

Cutaneous monoblastic leukemia as a first sign of relapse six years after autologous bone marrow transplantation for acute leukemia

A patient with acute monoblastic leukemia (AML, M5A) was treated successfully in December 1987. In 1993 after 6 years in complete remission, she presented with an intracutaneous nodular mass on her right upper arm which was resected in toto and shown to be undifferentiated monoblastic leukemia. Two further chloroma lesions were excised in July 1994 and March 1995 respectively. Bone marrow cytology and histology always showed a continuing complete remission with no evidence of leukemia relapse. In July 1995 she presented with a disseminated skin infiltrate and a relapse with 80% monoblasts in the bone marrow. After one course of chemotherapy (Idarubicin/Ara-C), a second complete remission was achieved and her leukemic skin infiltrate disappeared completely. This case illustrates that chloromas of the skin can occur as late as 6 years after treatment for AML and also emphasizes that the occurrence of a chloroma does not necessarily mean immediate leukemia relapse. It also stresses that a second complete remission can be achieved with standard AML-induction therapy despite widespread leukemic skin infiltrates in such patients.

Monoclonal antibodies Ki-S3 and Ki-S5 yield new data on the 'Ki-67' proteins

The monoclonal antibody (mab) Ki-67 has been used for about 10 years, mainly in tissue sections, to monitor proliferating cells, but so far only very little is known about the proteins it recognizes. The new mabs Ki-S3 and Ki-S5 detect proliferating cells in frozen and paraffin-embedded tissues. They recognize proteins with the same molecular mass as Ki-67 in Western blot and for the first time also in immunoprecipitation experiments. With these mabs we were able to enrich and purify the Ki-67 proteins. Protein sequencing of four peptides of the digested proteins corresponded to the cDNA-deduced amino acid sequence already published for the Ki-67 proteins. Since we were able to immunoprecipitate the Ki-67 proteins, we performed various immunoprecipitation experiments to obtain more information about the nature of these proteins. After radiolabelling L428 cells with [35S]-methionine we were able to immunoprecipitate the Ki-67 proteins after only 5 min of labelling time. In turnover experiments the Ki-67 proteins could not be detected 3 h after the end of labelling. These data indicate a half-life of the Ki-67 proteins of about 90 min. Labelling experiments with [32P]-orthophosphate revealed that the Ki-67 proteins are phosphorylated. After dephosphorylation was blocked with okadaic acid or cell growth was arrested by means of Colcemid, the phosphorylation of the Ki-67 proteins was greatly increased, indicating that the Ki-67 proteins are phosphorylated via serine and threonine, and that the phosphorylation of the Ki-67 proteins increases in cycling cells. Labelling experiments with [3H]-mannose and [3H]-glucose revealed that the protein is weakly N-glycosylated.

[Clonal B-cell reaction in Sjögren disease and Hashimoto autoimmune thyroiditis]

Autoimmune diseases are defined as specific, adapted immune reactions against self-antigens. These antigens were attacked by activated, autoaggressive T-Cells in most cases. However, since introduction of the MALT concept it became clear, that particularly in the autoimmune diseases of the MALT specific subpopulations of B-cells play an important role. In this study, the B-cells in the thyroid gland of 40 patients suffering from Hashimoto's disease and 25 patients with Sjögrens syndrome and enlargement of the salivary glands were immunophenotyped and molecular-genetically investigated. The molecular-genetical investigation included PCR based amplification of immunoglobulin heavy chain CDR III region and the T-cell receptor gamma chain (TCR-gamma). By immunophenotyping, in the salivary glands monocytoid B-cells could be identified as intraepithelial effector cells in nearly all cases, whereas in the thyroid gland mostly marginal zone cells in the follicle epithelium were observed. In 13 biopsy specimen from salivary gland, clonal rearrangements of TCR-gamma, and in 9 cases of patients with Sjögren's syndrome JH rearrangements could be detected. Monoclonal TCR-gamma rearrangements were identified in 9/40 patients suffering from autoimmunethyroiditis Hashimoto. In 8/40 thyroid gland biopsies a monoclonal JH-rearrangement could be found. Within 11/25 patients with Sjögren's syndrome and in 23/40 patients with M. Hashimoto polyclonal rearrangements were observed. Within all biopsy specimen of patients with monoclonal rearrangements, lymphoepithelial lesions or lymphoepithelial destructions could be identified immunohistochemically. Additionally, in 2 biopsies from salivary gland and in one specimen from thyroid gland the transition from autoimmune disease into a secondary high grade lymphoma was observed. In 26/40 patients with M. Hashimoto and in 11/25 patients with Sjögren's syndrome the transition in a subsequent low grade B cell lymphoma of MALT-type was found. These results lead to the following conclusions: 1. clonal rearrangements of tumor forming B-cells in both autoimmune diseases investigated can be interpreted as facultative malignant. 2. Intraepithelial B-cells probably are the promotors of the autoimmune process and--in case of clonal evolution and immortalisation--can be regard as causative agent in the development of primary extranodal B-cell lymphoma.

[Clonal B-cell reactions and prelymphoma in autoimmune diseases]

With the establishment of the MALT concept in immunology it became obvious that B cells play an important role in the autoimmune diseases of the MALT. We immunophenotyped the intraepithelial B cells occurring in Hashimoto's disease, Sjögren's syndrome and Helicobacter pylori-associated gastritis and looked for clonal T-cell receptor gamma chains (TCR-gamma) and immunoglobulin heavy chains (JH). Immunophenotypically, we identified predominantly monocytoid B cells as the effector cells in the salivary glands of patients with Sjögren's syndrome, whereas in the thyroid and stomach the effector cells were marginal zone cells. Polyclonal rearrangements were found in 11/25 patients with Sjögren's syndrome, 23/40 patients with Hashimoto's disease and 19/24 patients with gastritis. Accordingly, 14 of the patients with Sjögren's syndrome, 17 of the patients with Hashimoto's disease and 5 of the patients with gastritis showed monoclonal rearrangements. Immunohistochemically, all patients with clonal rearrangements were found to have lymphoepithelial lesions. In these patients a transition to a low grade MALT lymphoma could be diagnosed. From these results we can conclude that in these two autoimmune diseases clonal rearrangements must be considered at least potentially malignant and that intraepithelial B cells should probably be considered the promoters of autoimmune diseases and of the development of primary extranodal B-cell lymphomas.

[Castleman's disease: evaluation of 338 cases]

PURPOSE

To evaluate a large group of patients with Castleman's tumours (Castleman's disease = MC) with regard to age, sex and tumour localisation.

PATIENTS AND METHODS

338 cases of MC were evaluated. All cases were registered by the Lymphknotenregister of the German Society of Pathology, Kiel.

RESULTS

292 MC of the hyaline vascular type (MC-HV) and 46 of the plasma cell type (MC-PC) were found, 259 (76.6%) in nodal and 79 (23.4%) in extranodal localisation. Main nodal localisation were the neck (25.5%) and the axilla (12.8%). The mediastinum was involved in only 6.2%. There was a slight preference of female (56%) compared to male (44%). Patients with MC-PC (mean age: 50 +/- 16.9 years) were significantly older (p < 0.001) than patients with MC-HV (mean age: 39 +/- 18.9 years).

CONCLUSIONS

The main localisation of MC is the neck. MC-HV is more common than MC-PC. There is a slight preference for women. Mean age of patients with MC-PC is approximate 10 years higher than for MC-HV.

CD26 expression in leprosy and other granulomatous diseases correlates with the production of interferon-gamma

BACKGROUND

Leprosy represents a spectrum of clinical manifestations that reflect the immune response to antigens of Mycobacterium leprae. The tuberculoid form of leprosy, which is characterized by an organized development of granulomas, has recently been correlated with a Th1-like immune response. The lepromatous form of leprosy, with a characteristic lack of cellular immunity, has been correlated with a Th2-like immune response to mycobacterial antigens. Dipeptidylpeptidase IV (CD26) is an ectopeptidase that is expressed in various tissues; in the hemopoietic system, it is predominantly expressed by T cells.

EXPERIMENTAL DESIGN

We stained frozen sections of skin biopsies obtained from patients with different forms of leprosy, sarcoidosis, and Piringer's lymphadenitis. Sections were stained for interferon-gamma (IFN-gamma) and CD26 with the alkaline phosphatase anti-alkaline phosphatase technique and in two-color stainings by immunofluorescence.

RESULTS

We found strong signals for IFN-gamma and for CD26 in all investigated cases of tuberculoid leprosy. In contrast, in all biopsies taken from patients with lepromatous leprosy, we found no or very weak signals for these antigens. By immunofluorescence double-labeling, we could show that IFN-gamma and CD26 were expressed by the identical cell population. We confirmed this correlation of CD26 expression and IFN-gamma production in other granulomatous inflammatory reactions such as sarcoidosis and Piringer's lymphadenitis.

CONCLUSIONS

From our results, we conclude that a high expression of CD26 may be suggestive of Th1-like immune reactions.

Temperature gradient gel electrophoresis for analysis of clonal evolution in non-Hodgkin's lymphoma of the thyroid

To analyze the transition of an autoimmune disease into a mucosa-associated lymphoid tissue-non-Hodgkin's lymphoma (MALT-NHL), we investigated a total of 27 cases of clinically diagnosed autoimmune thyroiditis with lymphoid hyperplasia. Three cases of thyroid hyperplasia served as controls. Monoclonal B cells were detected by studying rearrangement patterns of the hypervariable CDR III regions within the immunoglobulin heavy chain gene locus and the T-cell receptor gamma chain gene (TCRG). We used a seminested polymerase chain reaction (PCR) to demonstrate immunoglobulin rearrangements and a multiplex PCR for TCRG rearrangements. The PCR products were analyzed by temperature gradient gel electrophoresis to expand mixtures of homo- and hetero-duplices within heterogeneous populations of B cells. With this approach we found monoclonality in 14 of the 27 cases of Hashimoto's disease. In a reinvestigation we discovered additional histological and immunohistochemical features of MALT-NHL in 17 cases. The 14 cases of thyroiditis with clonally expanded B cells clearly demonstrate the transition from autoimmune disease to non-Hodgkin's lymphoma.

Antidisialoganglioside ricin A-chain immunotoxins show potent antitumor effects in vitro and in a disseminated human neuroblastoma severe combined immunodeficiency mouse model

Several monoclonal antibodies (mAbs) were screened on different neuroblastoma cell lines to evaluate ricin A-chain immunotoxins for possible use against human neuroblastoma. Four mAbs were identified that exhibited high antitumor activity against neuroblastoma cell lines as measured in an indirect cytotoxicity assay. These mAbs, including 14G2a (antidisialoganglioside), ch14.18 (a humanized switch variant), BW704 (antidisialoganglioside), and chCE7 (anti-glycoprotein of M(r) 190,000), were subsequently linked via the bivalent linker N-succinimidyloxycarbonyl-alpha-methyl-alpha-(2-piridyldithio++ +)toluene to deglycosylated ricin A chain. The most potent immunotoxin, 14G2a.dgA, inhibited the protein synthesis of neuroblastoma cell lines IMR5 and NMB by 50% at concentrations of 6 x 10(-12) M. To test the antitumor efficacy of these immunotoxins in vivo, we developed a disseminated human neuroblastoma model in severe combined immunodeficiency mice. Treatment of tumor-bearing mice with 14G2a.dgA 12 days after tumor challenge resulted in a significant prolongation of survival as compared with phosphate-buffered saline-treated controls (16.8 versus 6.5 weeks). We conclude that ricin A-chain immunotoxins might be of potential use in the treatment of human neuroblastoma.

Follicular dendritic cells in non-Hodgkin's lymphomas

Follicular dendritic cells (FDC) are restricted to the B-cell regions of secondary lymphoid tissue and to non-Hodgkin's lymphomas derived from the follicular center or the mantle zone. With their cytoplasmic ramifications they form a dense network which contains the B-lymphocytes. In situ, FDC are only detectable at the ultrastructural level or when stained with anti FDC-reagents. On the surface of their dendritic extensions they express transferrin receptors (CD71), the B-cell epitope CD20, class II antigens, the myelomonocytic molecule CD14, the glycoprotein gp50 (CD40), and several receptors for components of the complement system (CD11b, CD21, CD35). Subsequent to an antigen challenge, FDC trap and retain immune-complexes for a long period of time. In vitro FDC and neoplastic lymphocytes spontaneously form small cellular aggregates. This adhesion is mediated by the LFA-1-alpha/beta = ICAM-1, the VLA-4 = VCAM-1, and the ICAM-1 = C3bi- receptor ligand pathways on B-cells and on FDC, respectively. The loss of LFA-1- alpha/beta and ICAM-1 molecules may enable neoplastic lymphocytes to detach from FDC. The monoclonal B-cells now invade new compartments. In vitro, FDC have the capacity to activate resting B-cells and to save them from dying by apoptosis. Signals involved in this activation include cell-surface immunoglobulin and CD40. Immunocytochemistry and autoradiography with single cell suspensions of neoplastic B cells suggest that FDC also provide signals leading to the continued stimulation of lymphoma lymphocytes. During the early stage of HIV infection lymph nodes show an immense follicular hyperplasia, with a massive increase of the dendritic network of FDC. In the later stage of the disease, the continuous involution of the germinal centers is associated with a progressive destruction of FDC.

[NHL-BFM 90 therapy study in treatment of malignant non-Hodgkin's lymphomas in children and adolescents. Part 1: Classification and allocation to strategic therapy groups. BIF study group]

One of the goals of the study NHL-BFM 90 was to investigate the distribution and prognosis of the different subtypes of Non-Hodgkin's Lymphoma (NHL) in children and adolescents according to histological, cytomorphological and immunological characteristics. From 4/1990 to 12/1992, 346 patients (pts) (84 females, 262 males) were enrolled (median age: 9.1 years; range: 0.8-17.9 years). Histology was available from 290 pts (84%), cytomorphology from 155 (44%), and immunophenotyping from 245 (70%). Cases with L1 oder L2 cytomorphology according to the French-American-British Classification were classified as lymphoblastic lymphoma and those with L3 cytomorphology as Burkitt-Type lymphoma or acute B-cell leukemia (B-ALL) if a histological classification was not available. By means of the combined analysis of all three diagnostic criterias the classification of the NHL according to the updated Kiel-classification was possible in 312 cases: 49% were classified as Burkitt-type-lymphoma (incl. B-ALL), 22% als lymphoblastic lymphoma, 10% as large cell anaplastic lymphoma (LCAL), 6% as centroblastic lymphoma, only few cases were classified as NHL of other subtypes, 3 pts (1%) suffered from low grade malignant lymphomas, and in 34 pts (10%) the NHL was not further classified. Patients were stratified according to NHL-subentities in 3 branches (Non-B-NHL, B-NHL, LCAL) of different treatment modalities. The estimated probability of a 3-year event free survival (pEFS) was 88 +/- 2% for the whole group (follow up 7 to 40 months, median 23 months) while pEFS of different subtypes was: lymphoblastic lymphoma: 91 +/- 4%; Burkitt-type-lymphoma/B-ALL: 90 +/- 2%; centroblastic lymphoma: 94 +/- 6%, LCAL: 88 +/- 6%. We conclude that the stratification of treatment modalities in study NHL-BFM 90 according to biological entities provided patients of different NHL-subtypes an equal chance to survive event free. The efficacy of the treatment strategy for rare subtypes, however, is not evaluable yet.

[Intensification of sensitivity of monoclonality determination of B-cells in autoimmune thyroiditis and low malignancy B-NHL of the MALT type using temperature gradient gel electrophoresis (TGGE)]

Malignant non-Hodgkins lymphoma with primary involvement of the thyroid is a rare disease. Nearly all these lymphomas are of B-cell phenotype, and they represent a broad morphological spectrum of high and low grade entities. We investigated 18 cases of Hashimotos disease and 95 cases of thyroid non-Hodgkins lymphoma including 16 cases of MALT-lymphoma. This type of lymphoma is often hardly distinguishable from reactive lesions, even by immunohistochemistry. Therefore, we introduced a new molecular genetic technique based on the polymerase chain reaction (PCR) combined with temperature-gradient gel electrophoresis to demonstrate monoclonal populations of B cells in a polyclonal background of reactive B lymphocytes. With this approach we found monoclonality in 4 of 18 cases of Hashimotos disease. In our opinion, these 4 cases demonstrate clearly the transition from autoimmune disease into non-Hodgkins lymphoma.

DNA content and the proliferation marker Ki-67 as prognostic indicators in renal cell carcinoma

Patients suffering from renal cell carcinoma have a generally poor prognosis. Even cases that are clinically in comparable stages can, however, take quite different courses. The basic prognostic factors, histological grade and TNM stage do not do justice to the heterogeneous biological behavior of this tumor entity. In this study, the possible prognostic indicators, DNA content and proliferation rate, assessed with Ki-67, were compared with the histological grade and the TNM stage. Though there was no correlation between the proliferation rate (Ki-67) and the two, there was a significant correlation between DNA content and both histological grade and TNM stage.