Interfollicular Zone Research Articles

Abstract 1355: Suppressors of cytokine signaling (SOCS) proteins are elevated in the melanoma microenvironment

Abstract Immunosuppressive cytokines (IL-6, IL-10, TGF-β) act to promote tumor growth and suppress immune function. Conversely, the interferons (IFNs) are critical for cancer immunosurveillance by host immune cells. The precise mechanisms in which effector functions of immune cells are regulated by these cytokines deserve further investigation. Signal transduction in response to IFNs can be negatively regulated by the Suppressors of Cytokine Signaling or SOCS proteins. Our laboratory has demonstrated that SOCS1 and SOCS3 negatively regulate the anti-tumor activity of exogenously administered IFN-α by reducing intracellular signaling responses. In fact, SOCS1-deficient mice were cured of lethal melanoma tumors, and this effect was dependent on CD8+ T cells (Zimmerer et al., J. Immunol., 2007). Therefore, we hypothesized that cytokines present in the tumor microenvironment exert their immunosuppressive actions via the up-regulation of SOCS proteins in immune cells, making them less responsive to the cytokines that mediate immune surveillance. Treatment of peripheral blood mononuclear cells with IL-6, IL-10 or TGB-β led to increased expression of SOCS1 or SOCS3 proteins and pre-treatment with these cytokines inhibited subsequent IFN-α induced signal transduction and gene expression as measured by Real Time PCR. Since expression of IL-6, IL-10 and TGF-β has been observed at the tumor site, we postulated that increased expression of SOCS1 or SOCS3 proteins might also be present and serve as an initial barrier to the actions of IFNs on immune effector cells located in the tumor microenvironment. Lymphatic tissue from sentinel node biopsies represents a unique opportunity to study the interactions between melanoma cells and immune cells in the microenvironment. We therefore characterized the expression of SOCS proteins in formalin-fixed paraffin-embedded specimens from melanoma-positive or melanoma-negative lymph node (LN) biopsies. In melanoma negative LN, SOCS1 protein showed a characteristic histologic pattern of expression as it was strongly expressed in sinusoidal or perivascular lymphatic vessels, with a small number of scattered SOCS1 positive cells in the interfollicular zones. SOCS3 protein was primarily expressed within sinusoidal cells. Little or no SOCS1 or SOCS3 proteins were expressed in germinal centers. Evaluation of melanoma-positive LN revealed the presence of SOCS1 and SOCS3 positive cells that localized to the lymphoid or monocytic cells, rather than the tumor cells themselves. Of note, immune cells in close proximity to the tumor (200µM) displayed prominent SOCS1 and SOCS3 staining. These data indicate that the presence of melanoma tumors in lymphatic tissue is associated with elevated SOCS1 and SOCS3 protein expression in immune effector cells. Together these data suggest that SOCS proteins may play a role in the immune modulation within the tumor microenvironment. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1355.

An approach to distinction between reactive and malignant lymphoid proliferation

Distinction between reactive and malignant lymphoid proliferation ranges from easy to difficult. Familiarity with the normal architecture and cell types is important. The following features would support a diagnosis of lymphoma, although no single feature is pathognomonic. Abnormal architecture : Morphologic: Effacement of architecture; expansile mass lesion within lymphoid proliferation; back-to-back arrangement of lymphoid follicles; abnormal appearance of follicles; coalescence of broad marginal zones. Immunohistochemical : Diffuse sheets of B cells or excessive B cells in interfollicular zone. Evidence of invasion : Morphologic: Invasion of epithelium/ gland; permeation of interstitial tissues or between glands; invasion of blood vessel walls; atypical lymphoid cells in interfollicular zone; destruction of mantles of lymphoid follicles; colonisation of lymphoid follicles. Immunohistochemical : Interfollicular zone rich in CD20 + B cells; interfollicular zone rich in CD10 + lymphoid cells. Cytologic atypia : Morphologic: Very large cells (>3 times diameter of small lymphocyte nuclei); most cells with irregular nuclei; granular chromatin; clear cells; many unexplained medium-sized cells. Immunohistochemical : Expression of precursor cell marker TdT; abnormal immunophenotype (aberrant pan-B or pan-T markers; light chain restriction); abnormal subset marker expression (e.g., CD4 + CD8 +double-positive or CD4–CD8–); expression of markers not normally expressed or expressed only in minority of the cell type.

Stroma-rich variant of hyaline-vascular Castleman's disease: a clinicopathologic and histogenetic study

To study the histologic features and immunohistochemical findings of interfollicular stromal cells in hyaline-vascular Castleman's disease (HVCD), and to explore the role of these stromal cells in the pathogenesis of this disease. The clinical findings and microscopic features of 23 cases of HVCD cases were reviewed. Immunohistochemical study for CCL21, MSA, CD21, CD35, S-100 and CD34 was carried out. According to the criteria proposed by Danon et al., stroma-rich variant of HVCD contained prominent interfollicular zone which occupied at least 50% of the lymph node area. In the current study, there were 14 cases of stroma-rich HVCD and 9 cases of conventional HVCD. Eleven of the stroma-rich HVCD had paraneoplastic pemphigus and contrastly, no pemphigus lesion obtained in all the 9 cases of conventional HVCD. The association between stromal cell hyperplasia and paraneoplastic pemphigus was statistically significant (P < 0.01).In all the conventional HVCD cases studied, CCL21 and MSA were positive in the stromal cells.The stromal cells in 13 of the 14 cases of the stroma-rich HVCD were also positive for CCL21 and MSA, however, staining for CD21, CD35, S-100 and CD34 was negative in both groups. There was no statistical significance obtained (P > 0.05) between the differences of the staining results. Stroma-rich HVCD and conventional HVCD represent two distinctive histologic variants and have a different association with paraneoplastic pemphigus. Most of the stromal cells locating in the interfollicular areas are fibroblastic reticular cells in origin, with the immunophenotype as CCL21(+)/MSA(+)/CD34⁻/CD21⁻/S-100⁻. The stromal cells proliferation correlate with the occurrence of paraneoplastic pemphigus, nevertheless, more cases are expected for a further study of the underlying pathogenesis.

Differences in transcriptomic profile and IgA repertoire between jejunal and ileal Peyer's patches

In many species such as sheep and pig, there are two types of Peyer's patches (PP): several discrete patches in the jejunum and a long and continuous patch in the ileum. Most of the immunoglobulin A in the gut is generated by B-cells in the PP germinal centers. Moreover, swine like ovine ileal PP might be important for antigen independent B-cell repertoire diversification. We examined, by quantitative real-time PCR, the expression of 36 transcripts of antimicrobial peptides, chemokines, interleukines, Toll-like receptors and transcription factors from both PP and we highlighted the differences by a principal component analysis. Ileal PP was characterized by a higher mRNA expression of CCL28, IL5, IL10, TLR2 and TLR4 while jejunal PP showed higher mRNA expression of antimicrobial peptides, CCL25, FOXP3, IL4, T-Bet, TSLP and SOCS2. Then, we analyzed some VDJ rearrangements to assess immunoglobulin repertoire diversity in jejunal and ileal PP from weaned piglets. The IgA and IgM repertoires were more diverse in ileal than in jejunal piglet PP. All these results could be related to the rarefaction of interfollicular T-cell zone and the presence in ileal versus jejunal lumen of a more diversified microflora. These findings shed a light on the functional differences between both PP.

Increased dimeric IgA-producing B cells in tonsils in IgA nephropathy determined by in situ hybridization for J chain mRNA.

The origin of mesangial IgA deposits in IgA nephropathy (IgAN) remains obscure. A significant proportion of deposited immunoglobulin is dimeric (J chain-positive). Previous studies of J chain expression within lymphoid tissue in IgAN have utilized antibodies which other investigators have found to be non-specific. To address this problem, we have developed and in situ hybridization (ISH) method for the detection of J chain mRNA within IgA plasma cells. Tonsils from 12 patients with IgAN and 12 controls were studied using (i) non-isotopic ISH for J chain mRNA, and (ii) combined immunofluorescence (IF) and fluorescent ISH. J chain mRNA-positive cells were identified in germinal centres, and within the subepithelial and interfollicular zones. A greater number of J chain mRNA-positive cells were found in the germinal centres of patients (mean 57.7 +/- 4.6 cells/10(5) micron2) compared with controls (mean 36.9 +/- 3.5 cells/10(5) micron2) (P < 0.001). Combined IF and fluorescent ISH showed a greater proportion of J chain mRNA-positive interfollicular IgA cells in patient tonsils (32 +/- 3.4%) compared with controls (21 +/- 2.3%; P < 0.02). These results indicate a shift towards dimeric IgA production in the tonsils in IgAN. In addition, the finding of excess numbers of J chain-positive Iga-negative cells within germinal centres suggests that an abnormality may be present at the B cell differentiation stage before IgA switching. These results further highlight immune abnormalities within the tonsil as a central feature of abnormal polymeric IgA biology in this common form of glomerulonephritis.

4. Gastrointestinal mucosal immunity

Mucosal surfaces constitute a large host-environmental interface that must be protected from pathogenic organisms. The mucosal immune system has evolved as a distinct immune organ functioning independently from its systemic counterpart. The mucosal immune system has the difficult task of mounting protective responses to invading microorganisms while maintaining a state of nonresponsiveness to commensal bacteria and food antigens. The system has unique cellular components and functional aspects that permit it to carry out this dual role.

Prediction of Nonsentinel Lymph Node Involvement in Patients with a Positive Sentinel Lymph Node in Malignant Melanoma

Completion lymph node dissection (CLND) is routinely performed after metastatic melanoma is detected at sentinel lymph node (SLN) biopsy. Nonsentinel lymph node (NSLN) involvement is found in less than one-third of the cases. Possible predictors of NSLN involvement are examined. A retrospective review of 70 patients with a positive SLN biopsy for melanoma and drainage to one lymphatic basin was performed. The size of metastatic deposits was defined as macrometastases (>2 mm), micrometastases (< or =2 mm), a cluster of cells (10-30 grouped cells) in the subcapsular space or interfollicular zone, or isolated melanoma cells (1-20 or more individual cells) in subcapsular sinuses. Tumor stage, ulceration, SLN tumor burden, mitoses, number of positive SLNs, and total number of lymph nodes removed were examined as predictors of NSLN involvement after CLND. Two additional models based on SLN tumor burden and the number of nodes biopsied were designed. Nineteen patients (24.3%) were found to have NSLN metastases after CLND. Tumor stage, ulceration, SLN tumor burden, mitoses, number of positive SLN, and number of lymph nodes removed were not statistically significant. Residual disease at CLND stratified by SLN tumor burden was: isolated melanoma cells, 0; cluster of cells, 8 (38.1%); < or =2 mm, 5 (20.8%); and >2 mm, 6 (27.3%). A comparison of the means for the models was not predictive of NSLN involvement. None of the risk factors or models examined could predict nonsentinel lymph node involvement with melanoma. The SLN sample and minimal SLN metastatic disease when defined as isolated clusters of cells warrant further study as a potential indicator against CLND after positive SLN.

BAFF-R, the major B cell–activating factor receptor, is expressed on most mature B cells and B-cell lymphoproliferative disorders

B cell-activating factor receptor (BAFF-R) is one of three known receptors for BAFF, a critical regulator of B- and T-cell function. In mice, BAFF-R is required for B-cell maturation and survival, and in mice and humans, the overproduction of BAFF is associated with autoimmune disease. We sought to determine the normal pattern of BAFF-R expression at specific stages of B- and T-cell development and whether this pattern of expression corresponds with related B- and T-cell neoplasms. Most circulating human B cells and a small subset of T cells are BAFF-R-positive. In reactive lymphoid tissues, BAFF-R is expressed by B cells colonizing the mantle zones, by a subset of cells within germinal centers, and rare cells in the interfollicular T-cell zone. BAFF-R is also expressed by B cells colonizing the splenic marginal zone. Seventy-seven (78%) of 116 cases of B-cell lymphoproliferative disorders were BAFF-R-positive by immunohistochemical and/or flow cytometric immunophenotypic analysis, including most cases of mantle cell lymphoma, follicular lymphoma, marginal zone lymphoma, chronic lymphocytic leukemia, hairy cell leukemia, and diffuse large B-cell lymphoma. In contrast, cases of precursor B lymphoblastic lymphoma, Burkitt lymphoma, and nodular lymphocyte-predominant Hodgkin lymphoma exhibit weak to negative staining for BAFF-R. All cases of classical Hodgkin lymphoma and T-cell lymphomas were BAFF-R-negative, including all cases of anaplastic large cell lymphoma, adult T-cell leukemia/lymphoma, angioimmunoblastic T-cell lymphoma, and peripheral T-cell lymphoma, unspecified. These findings highlight BAFF-R as a marker of both normal and neoplastic B cells and raise the possibility that BAFF-R expression is necessary for the survival of a subset of neoplastic B lymphocytes analogous to its known role in promoting normal B-cell maturation and survival.

Correlates of Immune Protection in Chickens Vaccinated with Mycoplasma gallisepticum Strain GT5 following Challenge with Pathogenic M. gallisepticum Strain R low

Colonization of the avian respiratory tract with Mycoplasma gallisepticum results in a profound inflammatory response in the trachea, air sacs, conjunctiva, and lungs. A live attenuated M. gallisepticum vaccine strain, GT5, was previously shown to be protective in chickens upon challenge; however, the mechanisms by which this vaccine and others confer protection remain largely unknown. The current study evaluated several potential correlates of GT5 vaccine-mediated immune protection following challenge with the pathogenic M. gallisepticum strain R(low). GT5-vaccinated chickens developed mild tracheal lesions, consisting of few and scattered, discrete, lymphofollicular aggregates in the lamina propria. In addition, low numbers of aggregated B, CD4(+), and CD8(+) cells were observed to infiltrate the trachea, in stark contrast to the large numbers infiltrating the tracheas of sham-vaccinated chickens challenged with R(low). Lymphofollicular aggregates were rarely observed prior to day 12 postchallenge in sham-vaccinated chickens. Instead, they contained an increasingly more cellular inflammatory response characterized by expansion of the lamina propria by lymphoplasmacytic and histiocytic infiltrates. This was due in part to expansion of interfollicular zones by large numbers of infiltrating CD4(+) and CD8(+) cells and a sizeable population of immunoglobulin A (IgA)- and IgG-secreting plasma cells. GT5-vaccinated chickens also had higher serum IgG concentrations, and significantly higher numbers of M. gallisepticum-specific IgG- and IgA-secreting plasma/B cells within the trachea, than did sham-vaccinated chickens. These responses were observed as early as day 4 postchallenge, indicating the importance of antibody-mediated clearance of mycoplasma in GT5-vaccinated chickens.

Distribution and phenotype of Epstein–Barr virus-infected cells in human pharyngeal tonsils

Although Epstein–Barr virus (EBV) is often found in human tonsils, it remains to be precisely determined in what cells and microenvironment the virus is present. Although generally regarded as a B lymphotropic virus, EBV is associated with non-B-cell tumors, for example, NK/T-cell lymphoma, carcinoma, and leiomyosarcoma. To provide a basis for understanding the origin and biology of EBV-infected non-B cells, the immunophenotype of all EBV-infected cells in reactive human tonsils was determined by subjecting tonsil sections to dual/triple EBER in situ hybridization and immunohistochemistry with monoclonal antibodies to T cells (CD3, CD4, CD8, CCR3), B cells (CD20), plasma cells (CD138), natural killer (NK) cells (PEN5), and epithelial cells (cytokeratin), as well as frozen section immunostaining with antibodies to EBV latent proteins EBNA1, EBNA2, LMP1, and EBV early protein BZLF1. Most tonsils contained nearly equal numbers of EBNA1- and LMP1-positive cells (latency program) while only a few contained EBNA2-positive cells (growth program). More than 1000 EBER-positive cells from six tonsils were detected in the interfollicular zone (59%), tonsillar crypts (26%), and follicles (15%). Most (82%) EBER-positive cells are CD20-positive B cells, 7% are CD3-positive T cells, and 11% are cells of indeterminate lineage, often with plasmacytoid morphology. However, no EBER-positive plasma cells were identified. Rare EBER-positive NK cells and EBER/BZLF1-positive epithelial cells were identified. The direct demonstration of EBV within rare T cells, NK cells, and epithelial cells in reactive human tonsils provide a basis for further understanding of the origin of EBV-associated tumors of non-B-cell type.

Angiofollicular lymph node hyperplasia (castleman's disease)—A case report

A 55 year's old female presented with a painless swelling on the left side of the neck of 20 year's duration. She had history of t rauma over" that region following which she noticed the swelling. It increased in size g radua l ly . It was p y r i f o r m in shape and f i rm in consistency. It occupied the entire left anterior triangle and part of the posterior triangle of the neck. She had no dysphagia, voice changes, weight loss or fever. No significant lymphadenopathy in other areas of the body could be detected. Liver and spleen were not palpable. Previous haematological tests, X rays neck and chests, thyroid scan, serum T3, T4 and TSH were within normal limits. Rheumatoid factor was negative. Her bleeding time and clotting time were 1 rain. 15 seconds and 4 rain. 20 seconds respectively. Fine needle Aspiration Cytology (FNAC) revealed non specific lymphadenitis. Excision biopsy revealed an oval firm encapsulated mass, externally covered with greyish white membrane, wi th prominent blood vessels and areas of shaggy looking fibrous adhesions. The specimen was 7.0 cm x 4.5 c m x 1.0 cm in size. Cut surface was irregular, lobulated and soft yellowish in colour. On microscopic examination, multiple sections revealed structure of a l y m p h node wi th cel lular infi l t rates. There were irregular bands of connective tissues, containing a large number of hyalinised blood vessels running fi'om the capsules to the interior, dividing the lymph node into lobules. Through out the specimen there were lymphoid follicles of varying sizes having both prominent and inconspicuous germinal centres, with hyalinised blood vessels in many of them and having a thick mantle zone of lymphocytes . The interfoll icular zone contained

Histological, histochemical and immunohistochemical study of the haemal nodes of the dromedary camel.

Haemal nodes are lymphoid organs found in various mammals and some birds. The structure of haemal nodes has been described in a number of species but not yet in the camel. Therefore, haemal nodes from 10 camels were studied histologically and tested for CD3, CD22, major histocompatibility complex (MHC) class II/DR, alpha-smooth muscle actin and for the demonstration of acid and alkaline phosphatases. The haemal nodes were of spherical or kidney shape with one or two hili and had a capsule and trabeculae of connective tissue and smooth muscles. The main parenchyma was composed of a cortex and a medulla. The cortex was formed from lymphoid follicles and diffuse interfollicular lymphocytes. The medulla consisted of lymphoid cords separated by medullary sinuses. The interfollicular lymphocytes and those in the medullary cord were CD3-positive. The lymphoid follicles showed CD22-positive cells. MHC class II/DR was expressed by most cells of the parenchyma. There were also subcapsular, peritrabecular and medullary blood sinuses. Afferent and efferent lymphatics and lymphatic sinuses were also found. Acid phosphatase-positive cells were localized mainly in the marginal, the interfollicular zone and in the medullary cord. Alkaline phosphatase positivity was observed in the endothelium of the sinuses and in the lymphoid follicles. The morphology of these organs in the camel allows a classification as haemolymph nodes and suggests involvement in blood and lymph filtration.

The amount of metastatic melanoma in a sentinel lymph node: does it have prognostic significance?

The amount of metastatic disease in the sentinel lymph node (SLN) is examined as a prognostic factor in malignant melanoma. SLN mapping was performed on 592 patients with stage I and II malignant melanoma from March 1, 1994, through December 31, 1999. One hundred four patients were found to have 134 sentinel SLNs containing metastatic melanoma. The slides were reviewed, and the size of the metastatic melanoma in each SLN was measured. The size of the metastatic deposit was defined as macrometastasis (>2 mm), micrometastasis (< or =2 mm), a cluster of cells (10-30 grouped cells) in the subcapsular space or interfollicular zone, or isolated melanoma cells (1 to > or =20 individual cells) in subcapsular sinuses. The number of metastases in each SLN was isolated melanoma cells, n = 5 (3.7%); cluster of cells, n = 35 (26.1%); < or =2 mm, n = 45 (33.6%); and >2 mm, n = 49 (36.7%). Seventy-nine patients (76%) had a single positive SLN. The size of the largest nodal metastasis was used to stratify patients with multiple positive SLNs. The overall 3-year survival for patients with SLN micrometastases was 90%, versus 58% for patients with SLN macrometastases (P =.004). The amount of metastatic melanoma in an SLN is an independent predictor of survival. Patients with SLN metastatic deposits >2 mm in diameter have significantly decreased survival.

Microbial colonization drives lymphocyte accumulation and differentiation in the follicle-associated epithelium of Peyer's patches.

Peyer's patches (PPs) are lined by follicle-associated epithelium (FAE) with Ag-transporting M cells. To investigate the spatial relationships of B cells, T cells, and dendritic cells (DCs) in PPs during microbial colonization, their in situ redistribution was examined in germfree (GF) rats exposed to a conventional pathogen-free microflora (conventionalized, CV). Although occasional B and T cells occurred in the FAE of GF rats, it contained mainly immature DCs (CD4(+)CD86(-)), whereas mature DCs (CD86(high)) were seen in the interfollicular zones even under GF conditions. In CV rats, DCs had disappeared from the FAE, which instead contained clusters by B and T cells associated with induction of putative M cell pockets. CD86 was seen neither in the FAE nor in the follicles under GF conditions, but it became apparent on intraepithelial B cells 5 wk after colonization. The level of CD86 on these B cells was comparable to that on germinal center B cells, although the B cell follicles did not show direct contact with the M cell areas. B cells in the follicular mantles acquired Bcl-2 after 12 wk in CV rats, whereas B cells in the FAE did not express Bcl-2 at a substantial level throughout the experimental period. The cellular redistribution patterns and phenotypic characteristics observed after colonization suggested that immature DCs, but not B cells, are involved in Ag presentation during primary immune responses against intestinal bacteria. However, the spatial cellular relationships sequentially being established among DCs, B cells, and T cells in PPs, are most likely important for the induction of post-germinal center B cells subsequently residing within the M cell pockets.

CD8 T cells are required for the formation of ectopic germinal centers in rheumatoid synovitis.

The assembly of inflammatory lesions in rheumatoid arthritis is highly regulated and typically leads to the formation of lymphoid follicles with germinal center (GC) reactions. We used microdissection of such extranodal follicles to analyze the colonizing T cells. Although the repertoire of follicular T cells was diverse, a subset of T cell receptor (TCR) sequences was detected in multiple independent follicles and not in interfollicular zones, suggesting recognition of a common antigen. Unexpectedly, the majority of shared TCR sequences were from CD8 T cells that were highly enriched in the synovium and present in low numbers in the periphery. To examine their role in extranodal GC reactions, CD8 T cells were depleted in human synovium-SCID mouse chimeras. Depletion of synovial CD8 T cells caused disintegration of the GC-containing follicles. In the absence of CD8 T cells, follicular dendritic cells disappeared, production of lymphotoxin-α1β2 markedly decreased, and immunoglobulin (Ig) secretion ceased. Immunohistochemical studies demonstrated that these CD8 T cells accumulated at the edge of the mantle zone. Besides their unique localization, they were characterized by the production of interferon (IFN)-γ, lack of the pore-forming enzyme perforin, and expression of CD40 ligand. Perifollicular IFN-γ+ CD8 T cells were rare in secondary lymphoid tissues but accounted for the majority of IFN-γ+ cells in synovial infiltrates. We propose that CD8+ T cells regulate the structural integrity and functional activity of GCs in ectopic lymphoid follicles.

Mantle Cell Lymphoma, “Blastoid” Variant (WHO Classification), Producing Distinctive Morphologic Patterns

Mantle cell lymphoma (MCL) comprises 7% of non-Hodgkin lymphomas. It can grow in several different architectural patterns including mantle zone, mantle cell nodular, follicular colonization, and diffuse. Cytologically, the mantle cell nuclei can range from round to slight to markedly irregular (classic), to blastoid, and to pleomorphic. They rarely have moderate amounts of cytoplasm and mimic marginal zone B cells. We present a most unusual case of MCL that displays mantle zone, mantle cell nodular, follicular colonization, marginal, inverse follicular, and interfollicular patterns. In the areas showing mantle zone, nodular, and follicular colonization, the mantle cells have round to slightly irregular nuclear contours, and show a high mitotic rate. In the areas displaying an interfollicular, inverse follicular, and marginal zone patterns, the mantle cells show selective transformation to large blastoid cells resembling lymphoblasts. The mitotic rate in these areas is exceedingly high. Immunophenotypically, both cytologic components are positive for CD20, CD5, CD43, and cyclin D1, confirming the MCL diagnosis.

Up-regulation of the chemokine receptor CCR7 in classical but not in lymphocyte-predominant Hodgkin disease correlates with distinct dissemination of neoplastic cells in lymphoid organs

Chemokines and chemokine receptors are key mediators for regulating cell traffic and positioning in both homeostatic and inflammatory conditions. It is also presumed that chemokines and their receptors are likely to play a critical role in the localization of malignant hematopoietic cells in their target organs. This study analyzed chemokine and chemokine receptor expression in several Hodgkin disease (HD)-derived cell lines and in HD tumors. All HD-derived cell lines expressed functional CCR7 and CXCR4 receptors. CCR7 up-regulation was mediated by constitutive NF-kappaB activity. Lymphoid tissues in HD revealed differential expression levels of CCR7, CXCR4, and CXCR5, depending on the distinct subtypes of HD. HD of the classical subtypes, predominantly located in the interfollicular zone, showed strong CCR7 and CXCR4 expression and moderate CXCR5 expression. In contrast, the nodular lymphocyte-predominant HD (NLP) subtype, regularly associated with follicular structures, exhibited no CCR7 reactivity but abundant CXCR4 staining. Their respective chemokine ligands showed marked expression by reactive cells within the tumors of classical HD and outside of the tumor nodules in NLPHD. Functionally, such differential chemokine receptor expression might contribute to specific localization and confinement of neoplastic cells within the target organs in the distinct HD entities.

Reduction of Hematopoietic Cell-Specific Tyrosine Phosphatase SHP-1 Gene Expression in Natural Killer Cell Lymphoma and Various Types of Lymphomas/Leukemias: Combination Analysis with cDNA Expression Array and Tissue Microarray

To investigate the lymphomagenesis of NK/T lymphoma, we comprehensively and systematically analyzed the expression pattern of the human NK/T cell line (NK-YS) genome by cDNA expression array and tissue microarray. We detected significant changes in the gene expression of NK-YS cell line: an increase in 18 and a decrease in 20 genes compared to normal NK cells or peripheral blood mononuclear cells. Among these genes, we found a strong decrease in hematopoietic cell specific protein-tyrosine-phosphatase SH-PTP1 (SHP1) mRNA by cDNA expression array and reverse transcriptase-polymerase chain reaction. Further analysis with standard immunohistochemistry and tissue microarray, which used 207 paraffin-embedded specimens of various kinds of malignant lymphomas, showed that 100% of NK/T lymphoma specimens and more than 95% of various types of malignant lymphoma were negative for SHP1 protein expression. On the other hand, SHP1 protein was strongly expressed in the mantle zone and interfollicular zone lymphocytes in reactive lymphoid hyperplasia specimens. In addition, various kinds of hematopoietic cell lines, particularly the highly aggressive lymphoma/leukemia lines, lacked SHP1 expression in vitro, suggesting that loss of SHP1 expression may be related to not only malignant transformation, but also tumor cell aggressiveness. SHP1 expression could not be induced in either of two NK/T cell lines by phorbol ester, suggesting that genetic impairment or modification with methylation of SHP1 DNA could be one of the critical events in the pathogenesis of NK/T lymphoma. This evidence strongly suggests that loss of SHP1 gene expression plays an important role in multistep tumorigenesis, possibly as an anti-oncogene in the wide range of lymphomas/leukemias as well as NK/T lymphomas.

A clinicopathologic series of 22 cases of tonsillar granulomas.

Tonsils are uncommonly affected by granulomatous inflammation, often with an obscure cause. This study attempts to elucidate the nature of tonsillar granulomatous inflammation. Retrospective clinicopathologic review. Twenty-two cases of tonsillar granulomas diagnosed between 1940 and 1999 were retrieved from the files of the Armed Forces Institute of Pathology. H&E slides and a series of histochemical stains were reviewed, and patient follow-up was obtained. There were 11 males and 11 females, aged 7 to 64 years (mean, 29.9 y). Most of the cases presented bilaterally (n = 19) with sore throat, dysphagia, and/or nasal obstruction. The clinical differential included chronic tonsillitis, tuberculosis, nonspecific infection, sarcoidosis, and a neoplasm. Histologically, the granulomas were focal and scattered, or diffuse, identified in the interfollicular zones (n = 16) and/or the germinal centers (n = 13), and occasionally associated with necrosis (n = 6). Based on histochemical and clinical follow-up information, the etiology of the granulomas included sarcoidosis (n = 8), tuberculosis (n = 3), Hodgkin's lymphoma (n = 2), toxoplasmosis (n = 1), squamous cell carcinoma (n = 1), and no specific known cause (n = 7). Twelve patients were either alive at last follow-up or had died with no evidence of disease (mean, 12.4 y), and 9 were either alive at last follow-up or had died with disease (mean, 24.9 y). One patient was alive with unknown disease status (lost to follow-up after 13.3 y). Although a cause for tonsillar granulomas is frequently identified, a number may not develop an identifiable etiology, with the granulomas probably representing an exaggerated immune response to chronic tonsillitis. However, a careful work-up must be conducted to exclude specific causes and avoid clinical mismanagement.

TCL1 oncogene expression in AIDS-related lymphomas and lymphoid tissues.

AIDS-related non-Hodgkin's lymphoma (AIDS NHL) comprises a diverse and heterogeneous group of high-grade B cell tumors. Certain classes of AIDS NHL are associated with alterations in oncogenes or tumor-suppressor genes or infections by oncogenic herpesviruses. However, the clinically significant class of AIDS NHL designated immunoblastic lymphoma plasmacytoid (AIDS IBLP) lacks any consistent genetic alterations. We identified the TCL1 oncogene from a set of AIDS IBLP-associated cDNA fragments generated by subtractive hybridization with non-AIDS IBLP. Aberrant TCL1 expression has been implicated in T cell leukemia/lymphoma development, and its expression also has been seen in many established B cell tumor lines. However, TCL1 expression has not been reported in AIDS NHL. We find that TCL1 is expressed in the majority of AIDS IBLP tumors examined. TCL1 protein expression is restricted to tumor cells in AIDS IBLP tissue samples analyzed with immunohistochemical staining. Hyperplastic lymph node and tonsil also exhibit strong TCL1 protein expression in mantle zone B cells and in rare interfollicular zone cells, whereas follicle-center B cells (centroblasts and centrocytes) show weaker expression. These results establish TCL1 as the most prevalent of all of the surveyed oncogenes associated with AIDS IBLP. They also indicate that abundant TCL1 expression in quiescent mantle zone B cells is down-regulated in activated germinal center follicular B cells in parallel to the known expression pattern of BCL-2. High-level expression in nonproliferating B cells suggests that TCL1 may function in protecting naïve preactivated B cells from apoptosis.