Follicular dendritic cells in non-Hodgkin's lymphomas

The essential microenvironmental role of oligomannoses specifically inserted into the antigen-binding sites of lymphoma cells

ABSTRACT

There are 2 mandatory features added sequentially en route to classical follicular lymphoma (FL): first, the t(14;18) translocation, which upregulates BCL2, and second, the introduction of sequence motifs into the antigen-binding sites of the B-cell receptor (BCR), to which oligomannose-type glycan is added. Further processing of the glycan is blocked by complementarity-determining region-specific steric hindrance, leading to exposure of mannosylated immunoglobulin (Ig) to the microenvironment. This allows for interaction with the local lectin, dendritic cell-specific ICAM-3-grabbing nonintegrin (DC-SIGN), expressed by tissue macrophages and follicular dendritic cells. The major function of DC-SIGN is to engage pathogens, but this is subverted by FL cells. DC-SIGN induces tumor-specific low-level BCR signaling in FL cells and promotes membrane changes with increased adhesion to VCAM-1 via proximal kinases and actin regulators but, in contrast to engagement by anti-Ig, avoids endocytosis and apoptosis. These interactions appear mandatory for the early development of FL, before the acquisition of other accelerating mutations. BCR-associated mannosylation can be found in a subset of germinal center B-cell-like diffuse large B-cell lymphoma with t(14;18), tracking these cases back to FL. This category was associated with more aggressive behavior: both FL and transformed cases and, potentially, a significant number of cases of Burkitt lymphoma, which also has sites for N-glycan addition, could benefit from antibody-mediated blockade of the interaction with DC-SIGN.

3D analyses reveal T cells with activated nuclear features in T-cell/histiocyte-rich large B-cell lymphoma

Nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL) can show variable histological growth patterns and present remarkable overlap with T-cell/histiocyte-rich large B-cell lymphoma (THRLBCL). Previous studies suggest that NLPHL histological variants represent progression forms of NLPHL and THRLBCL transformation in aggressive disease. Since molecular studies of both lymphomas are limited due to the low number of tumor cells, the present study aimed to learn if a better understanding of these lymphomas is possible via detailed measurements of nuclear and cell size features in 2D and 3D sections. Whereas no significant differences were visible in 2D analyses, a slightly increased nuclear volume and a significantly enlarged cell size were noted in 3D measurements of the tumor cells of THRLBCL in comparison to typical NLPHL cases. Interestingly, not only was the size of the tumor cells increased in THRLBCL but also the nuclear volume of concomitant T cells in the reactive infiltrate when compared with typical NLPHL. Particularly CD8⁺ T cells had frequent contacts to tumor cells of THRLBCL. However, the nuclear volume of B cells was comparable in all cases. These results clearly demonstrate that 3D tissue analyses are superior to conventional 2D analyses of histological sections. Furthermore, the results point to a strong activation of T cells in THRLBCL, representing a cytotoxic response against the tumor cells with unclear effectiveness, resulting in enhanced swelling of the tumor cell bodies and limiting proliferative potential. Further molecular studies combining 3D tissue analyses and molecular data will help to gain profound insight into these ill-defined cellular processes.

Fibroblasts in Nodular Sclerosing Classical Hodgkin Lymphoma Are Defined by a Specific Phenotype and Protect Tumor Cells from Brentuximab-Vedotin Induced Injury

Classical Hodgkin lymphoma (cHL) is one of the most common malignant lymphomas in Western Europe. The nodular sclerosing subtype of cHL (NS cHL) is characterized by a proliferation of fibroblasts in the tumor microenvironment, leading to fibrotic bands surrounding the lymphoma infiltrate. Several studies have described a crosstalk between the tumour cells of cHL, the Hodgkin- and Reed-Sternberg (HRS) cells, and cancer-associated fibroblasts. However, to date a deep molecular characterization of these fibroblasts is lacking. Thus, the aim of the present study is a comprehensive characterization of these fibroblasts. Gene expression profiling and methylation profiles of fibroblasts isolated from primary lymph node suspensions revealed persistent differences between fibroblasts obtained from NS cHL and lymphadenitis. NS cHL derived fibroblasts exhibit a myofibroblastic phenotype characterized by myocardin (MYOCD) expression. Moreover, TIMP3, an inhibitor of matrix metalloproteinases, was strongly upregulated in NS cHL fibroblasts, likely contributing to the accumulation of collagen in sclerotic bands of NS cHL. As previously shown for other types of cancer-associated fibroblasts, treatment by luteolin could reverse this fibroblast phenotype and decrease TIMP3 secretion. NS cHL fibroblasts showed enhanced proliferation when they were exposed to soluble factors released from HRS cells. For HRS cells, soluble factors from fibroblasts were not sufficient to protect them from Brentuximab-Vedotin induced cell death. However, HRS cells adherent to fibroblasts were protected from Brentuximab-Vedotin induced injury. In summary, we confirm the importance of fibroblasts for HRS cell survival and identify TIMP3 which probably contributes as a major factor to the typical fibrosis observed in NS cHL.

The degree of overlap between the follicular dendritic cell meshwork and tumor cells in mantle cell lymphoma is associated with prognosis

This study concerning mantle cell lymphoma (MCL) investigated retrospectively an association between patient prognosis and the percentage of the total number of lymphoma cells found in the follicular dendritic cell (FDC) meshwork, that is, the degree of overlap of lymphoma cells. Two hundred and nine MCL patients were apportioned to grades I-III, in which the CD21-positive FDC meshwork covered ≤50%, 51%-89%, and ≥90% of the tumor area, respectively. Significant differences among the grades (all, P < 0.01) were found in the following: duration of disease (from onset of clinical manifestation to diagnosis); clinical staging; extranodal involvement (non-lymphoid organs); histological subtype; and Ki-67 proliferation index (PI). After removing the aggressive variants, the overall survival rates of grade I (n = 92) and II (n = 57) patients were similar. The overall survival rates of grade III (n = 46) patients differed from that of grade I + II patients (P < 0.01). The grades negatively correlated with the Ki-67 PI value (r = -0.234, P = 0.001). At each grade the OSR of patients with Ki-67 PI ≤30% was similar to that of patients with Ki-67 >30%. In the Ki-67 PI ≤30% group, the OSRs of the patients differed significantly among the grades. In the Ki-67 >30% group the OSRs of the grades were similar. The results of multivariate Cox regression analysis showed that the degree of overlap, age and Ki-67 PI was the independent prognostic factors of the OSRs of MCL patients. Our data suggests that MCL patients in whom there was a high degree of overlap between the FDC meshwork and tumor area have a better clinical prognosis. The degree of overlap correlates well with the Ki-67 PI, which can be used to predict the prognosis of patients.

Neutrophils protect lymphoma cells against cytotoxic and targeted therapies through CD11b/ICAM-1 binding

Innate immune cells constitute a substantial proportion of the cells within the tumor microenvironment. Besides the contribution of the microenvironment to tumor proliferation and survival, there is direct evidence that interactions between tumor cells and their microenvironment alter sensitivity to anti-cancer agents. Neutrophils, a key player in the innate immune system, have been less studied than many other immune cells regarding their impact on cancer cell response to anti-cancer agents. In our 2D and 3D coculture systems, human neutrophils and differentiated HL60 cells attenuated the sensitivity of various lymphoma cell lines to several anti-cancer agents, including targeted therapies. Neutrophil-induced protection was dependent on cell-cell interaction between CD11b and ICAM-1 expressed by neutrophils and B cells, respectively and was shown to be Mcl-1-dependent. The protective effect of neutrophils was validated in vivo using immune-compromised mice inoculated with human NHL with our without neutrophils then followed by treatment with chemotherapy. Similar findings were made on primary cells purified from patients with chronic lymphocytic leukemia, treated with fludarabine or targeted agents in the presence of autologous neutrophils. In a clinical study, patients with non-Hodgkin's lymphoma with increased neutrophil counts displayed a reduced response rate to therapy. These findings reveal a novel protective mechanism of neoplastic B cells involving innate immune cells which could be pharmacologically targeted to enhance the antitumor effect of therapy.

Expression of multidrug resistance 1 gene in B-cell lymphomas: association with follicular dendritic cells

AIMS

  Multidrug resistance (MDR) in B-cell lymphomas still constitutes a major obstacle to the effectiveness of chemotherapy even in the anti-CD20 antibody therapy era. The aim of this study was to investigate the expression of MDR-associated molecules in reactive lymphadenopathy (RL), follicular lymphoma (FL), and diffuse large B-cell lymphoma (DLBCL).

METHODS AND RESULTS

  The expression of mRNA for ABC-transporter family genes was determined by real-time RT-PCR in lymph nodes from RL, FL, and DLBCL cases. MDR1 exhibited significantly stronger expression in RL, FL, and DLBCL than Raji B-cell lymphoma cells. RL and FL showed significantly higher expression than DLBCL. Immunohistochemically, MDR1 positive cells were localized in the germinal centers of RL and center of the nodular lesions of FL showing associations with CD21 positive follicular dendritic cells (FDCs). Raji cells were co-cultured with FDC sarcoma-derived cells and the expression of MDR1 and drug resistance were analyzed. The co-culture of Raji cells with FDCs induced strong expression of MDR1 and introduced resistance to doxorubicin-induced apoptosis.

CONCLUSIONS

  These results suggest that FDCs induce MDR1 expression in reactive as well as neoplastic B-cells. Inhibition of the interaction of FDCs with B-cells may provide a novel strategy for treating the chemotherapy resistant fraction.

Dendritic cells are significantly reduced in non-Hodgkin's lymphoma and express less CCR7 and CD62L

Despite the lack of tumor control, infiltration of immune cells has been demonstrated for several malignancies including non-Hodgkin's lymphoma. Since dendritic cells play a pivotal role in the initiation and control of the immune response, the frequency and phenotype of recently described sub-types of dendritic cells in non-Hodgkin's lymphoma were characterized. Myeloid and plasmacytoid dendritic cells were analysed in 55 non-Hodgkin's lymphoma and 33 reactive lymph nodes by flow cytometry and immunohistochemistry. Overall frequency of dendritic cells in reactive lymph nodes was higher than in non-Hodgkin's lymphoma while the pDC/mDCs ratio was comparable. The low frequency of dendritic cells in infiltrated lymph nodes was confirmed by immunohistochemistry; however, no significant difference in the distribution within lymphoid and tumor tissue was detected. For further characterization of the dendritic cells in non-Hodgkin's lymphoma, the expressions of adhesion molecules, costimulatory molecules, chemokine receptors and activation markers were assessed. Interestingly, a significantly decreased expression of CD62L and CCR7, receptors necessary for homing to lymph nodes, was identified in dendritic cells in non-Hodgkin's lymphoma, potentially explaining the lack of these cells. Taken together, dendritic cells are phenotypically altered and reduced in number in NHL, potentially contributing to the loss of tumor control in these patients.

Dendritic cells interacting mainly with B cells in the lymphoepithelial symbiosis of the human palatine tonsil

The lymphoepithelial symbiosis (LES) of the human palatine tonsil is composed of spindle- or star-shaped epithelial cells forming a loose meshwork, containing numerous lymphocytes and dendritic cells (DCs). In the present study, we immunohistochemically characterized DCs in the LES (LES-DCs). LES-DCs were phenotypically immature DCs that were S100beta+, fascin-, HLA-DR+, CD1a-, CD80-, CD83-, CD86-, and CD123-. The most characteristic feature of LES-DCs was that they contacted many B cells, which were mostly IgM+ IgD+ resting naive B cells. Langerhans cells (LCs) located in the nonsymbiotic squamous epithelium were immature DCs that were S100beta+, fascin-, and CD1a+ and did not contact lymphocytes. In contrast to LES-DCs, interdigitating dendritic cells (IDCs) in the T zone were mature DCs that were HLA-DR+, CD1a-, fascin+, CD80+, CD83+, and CD86+ and contacted numerous CD4+ T cells. Two subsets of IDC, S100beta+ fascin+ IDC (IDC-1) and S100beta- fascin+ IDC (IDC-2), were identified, and the majority of IDCs are IDC-2. In contrast to IDCs, which were distributed in the T-cell area in groups, LES-DCs were distributed along the crypt as if forming a barrier. These findings suggest that LES-DCs are a novel type of DC playing an important role in the induction of humoral immune response against incoming air- or food-borne pathogenic antigens.

Statins Could Be Used to Control Replication of Some Viruses, Including HIV-1

Statins are mainly known for their plasma cholesterol-lowering properties and are widely used for the prevention of cardiovascular diseases. They however also exert pleiotropic effects through a variety of mechanisms, among which several immunosuppressive effects that are unrelated to their cholesterol-lowering activity. Interestingly, there has been recent evidence of antiviral effects, including preliminary studies on the efficacy of statins against HIV-1. This paper more particularly focuses on the specific inhibition of the binding of leukocyte function-associated antigen-1 (LFA-1) to intercellular adhesion molecule (ICAM-1) by statins, independently of the inhibition of HMGCoA reductase. Targeting the statin-binding site within LFA-1 or regulating LFA-1 affinity by inhibiting prenylation of the small GTPases could prove useful to treat inflammatory, autoimmune diseases and possibly viral infections, including HIV-1.

Growth pattern and distribution of follicular dendritic cells in mantle cell lymphoma: a clinicopathological study of 96 patients

Mantle cell lymphoma (MCL) is an aggressive lymphoma with accepted risk factors such as proliferation markers. To date, the different follicular dendritic cell (FDC) patterns have never been analyzed in comparison with the overall survival time. Lymph node biopsy specimens from 96 patients were analyzed by conventional morphology and immunohistochemistry with antibodies against cluster differentiation (CD)20, CD5, CD23, cyclin D1, and FDC (Ki-M4P). Two groups can be distinguished with different FDC patterns: a nodular pattern in 79 cases and a diffuse pattern in 17 cases. A Kaplan-Meier analysis revealed significantly better survival for the nodular group (p=0.0312). This group was subdivided into a group with a nodular FDC pattern similar to the FDC distribution in primary follicles (PF-nodular in 72 cases) and one with a nodular FDC pattern resembling the colonization of germinal centers (GCs) by tumor cells (GC-nodular in seven cases). A Kaplan-Meier analysis showed that patients with MCL with a PF-nodular FDC pattern had a significantly better clinical outcome than patients with the other two patterns (p=0.0033). If only cases with classical cytology (n=79) were analyzed (blastoid types excluded), patients with a PF-nodular FDC pattern had a better clinical outcome (p=0.0008). The distribution of FDC in MCL is a diagnostic tool for identifying patients with a better clinical prognosis.

Microenvironmental interactions and survival of CLL B-cells

Chronic Lymphocytic Leukemia (CLL) B cells display characteristics consistent with a defect in programmed cell death (apoptosis) and exhibit prolonged survival in vivo. When recovered from peripheral blood or lymphoid tissues from the patient and cultured in vitro, these malignant cells rapidly undergo spontaneous apoptosis. This observation suggests that the selective survival advantage enjoyed by CLL B-cells is not entirely autonomous, raising the possibility of manipulating CLL B-cell survival by iatrogenic means. The extended survival of the neoplastic B-cells creates a permissive soil on which oncogene activation, genetic instability and accumulation of gene mutations favoring disease progression can occur. In addition, such survival-promoting microenvironments can rescue leukemia cells from cytotoxic therapy, giving way to disease relapse. Survival of CLL B-cells is influenced by interactions with non-leukemia cells in the microenvironment of lymph nodes, marrow and other tissues. CLL B-cells have developed many different ways to escape undergoing apoptosis. These include: (a) expression of survival receptor as well as their ligands, giving rise to autocrine survival pathways which are leukemia cell specific; (b) defects in plasma membrane receptor cell signaling, triggered by death receptors such as Fas- and TRAIL; and (c) constitutively active survival signaling pathways such as NFkappaB and PI3K/Akt. Here we discuss some of the molecular mechanisms by which interaction with other cells and factors in the microenvironment provides survival advantages to CLL B-cells in specific in vivo niches, and we suggest some strategies for overcoming these anti-apoptotic mechanisms for improving treatment of CLL.

Disappearance of CD21-positive follicular dendritic cells preceding the transformation of follicular lymphoma: immunohistological study of the transformation using CD21, p53, Ki-67, and P-glycoprotein

Some follicular lymphomas histologically transform into diffuse aggressive lymphomas, the prognosis of which is poor. There are, however, no reliable histological criteria for predicting which cases will later undergo such transformation. In low-grade B-cell lymphomas, follicular dendritic cells form dense mesh-like networks that contain accumulating neoplastic B-cells. These are rare in high-grade lymphomas. We immunohistochemically analyzed CD21-positive follicular dendritic cells in 32 follicular lymphomas, including 3 transformed lymphomas, in addition to immunohistological study using P-glycoprotein, p53, and Ki-67. We found that the mesh-like networks in follicles are more clearly defined in low-grade lymphomas than in high-grade lymphomas (p = 0.015). Neoplastic follicles in 2 transformed lymphomas lost the networks of follicular dendritic cells before transformation despite the existence of morphologically clear follicles. This differed from the non-transformed cases of the same cytological grades. Prognosis was statistically better for patients with low-grade tumor than for those with high-grade tumor (p = 0.026), and there was a trend toward poorer survival among CD21-negative cases (p = 0.186). P-glycoprotein, p53, and Ki-67 expressions did not provide sufficient information to predict the transformation of follicular lymphoma. The presence of CD21-positive follicular dendritic cells in neoplastic follicles might help predict the potential of follicular lymphoma to transform to diffuse large B-cell lymphoma.

FDC-B1: a new monoclonal antibody directed against bovine follicular dendritic cells

Follicular dendritic cells (FDCs) are a unique population of accessory cells located in the light zone of the germinal centres of lymphoid follicles. Their involvement in the generation of humoral immune responses implies a potential role for these cells in many disorders. Indeed, in prion diseases, FDCs seem to be the major sites of extraneuronal cellular prion protein expression and the principal sites of the infectious agent accumulation in lymphoid organs. The identification of FDC is useful for the analysis of their distribution in reactive lymphoid tissue as well as in pathological conditions. The production and characterisation of a new mouse monoclonal antibody directed against bovine follicular dendritic cells (FDC-B1) is reported. The antigen detected by FDC-B1 is expressed exclusively on the surface of FDCs in ruminant lymphoid organs. The antigen has an approximate molecular weight of 28 kDa.

In vivo expression of interleukin-8, and regulated on activation, normal, T-cell expressed, and secreted, by human germinal centre B lymphocytes

T-cell homing within germinal centres (GCs) is required for humoral B-cell responses. However, the mechanisms implicated in the recruitment of T cells into the GC are not completely understood. Here we show, by immunohistology, and Northern and Western blots, that in vivo human GC B lymphocytes can express CxC and CC chemokines. Moreover, B-cell subset-specific experiments reveal that interleukin (IL)-8 and regulated on activation, normal, T-cell expressed, and secreted (RANTES) are predominantly expressed by GC centroblast and centrocytes, suggesting that chemokine expression is essential at stages in which B-lymphocytes engage in active antigen-dependent interactions with T lymphocytes. In keeping with this hypothesis, we show that the T cells recruited into the GC correlatively express the receptors for IL-8 and RANTES. We propose that chemokine expression is a key B-cell function that facilitates T-lymphocyte recruitment into the GCs and supports cognate B-cell : T-cell encounters. Moreover, our data are consistent with the impaired homing of T cells to secondary lymphoid organs in mice that are either deficient in CC and CxC chemokines or their receptors.

Protection of CLL B cells by a follicular dendritic cell line is dependent on induction of Mcl-1

Chronic lymphocytic leukemia (CLL) B cells have defects in apoptosis pathways and therefore accumulate in vivo. However, when removed from the patient and cultured in vitro, these malignant cells rapidly undergo apoptosis. Recent studies suggest that leukemia cell survival is influenced by interactions with nonleukemia cells in the microenvironment of lymph nodes, marrow, and other tissues. To model such cell-cell interactions in vitro, we cultured freshly isolated CLL B cells with a follicular dendritic cell line, HK. CLL B cells cocultured with HK cells were protected from apoptosis, either spontaneous or induced by treatment with anticancer drugs. Protection against spontaneous apoptosis could also be induced by coculturing the CLL B cells with normal dendritic cells (DCs) or with a CD40-ligand (CD154)–expressing fibroblast cell line. Examination of the expression of several apoptosis-regulatory proteins revealed that coculture with HK cells or DCs induced up-regulation of the antiapoptotic Bcl-2 family protein Mcl-1 in CLL B cells, whereas CD40 ligation increased expression of Bcl-XL. Cell-cell contact was required for HK-induced protection, and introducing neutralizing antibodies against various adhesion molecules showed that CD44 was involved in HK-mediated survival, whereas CD40, intercellular adhesion molecule–1 (ICAM-1) and vascular cell adhesion molecule–1 (VCAM-1) were not. Anti-CD44 antibodies also blocked Mcl-1 induction by HK cells. Mcl-1 antisense oligonucleotides reduced leukemia cell expression of Mcl-1, and significantly suppressed HK-induced protection against apoptosis, whereas control oligonucleotides had no effect. Thus, HK cells protect CLL B cells against apoptosis, at least in part through a CD44-dependent mechanism involving up-regulation of Mcl-1, and this mechanism is distinct from that achieved by CD40 ligation. Consequently, the particular antiapoptotic proteins important for CLL survival may vary depending on the microenvironment.

Follicular Dendritic Cells Protect Malignant B Cells from Apoptosis Induced by Anti-Fas and Antineoplastic Agents

The observation that follicular dendritic cells (FDC) reduce apoptosis in B cells prompted the hypothesis that FDC might enhance tumor cell survival by protecting malignant B cells from apoptotic death. To test this notion, apoptosis was induced in B cell lymphomas by anti-Fas or various antineoplastic agents in the presence and absence of FDC. Apoptosis was detected and quantified by TUNEL analysis. Induction of apoptosis with anti-Fas, etoposide, cyclophosphamide, and busulfan was markedly antagonized by FDC at FDC to B cell ratios of ≥1:16. For example, treatment with 10 ng/ml anti-Fas caused 60–90% of A20 cells to undergo apoptosis in 6 h, whereas addition of FDC reduced apoptosis to background levels (3–15%). Similarly, treatment with busulfan induced apoptosis in 55–80% of A20 cells, whereas addition of FDC reduced B cell death to ≤15%; moreover, depletion of FDC abrogated the protective actions. In contrast, the apoptosis-inducing effect of Adriamycin was not reversed by FDC. The ability to block apoptosis induced by anti-Fas or busulfan was not limited to A20 but was observed in four other malignant pre-B cell or B cell lines. The mechanism by which FDC spare malignant B cells from apoptosis did not involve alterations in levels of Bcl-2, Bcl-XL, or Bax. Collectively, these data raise the possibility that FDC may enhance tumor cell survival by protecting malignant B cells against apoptosis induced by anti-Fas and some but not all chemotherapeutic agents.

Characterization of germinal center dendritic cells in follicular lymphoma

A subset of dendritic cells called germinal center dendritic cells (GCDC) has recently been described inside germinal center from reactive lymphoid organs. We investigated this newly recognized population in follicular lymphoma (FL), which is considered to be the pathologic counterpart of germinal center B cells. Immunohistochemistry analysis with a panel of antibodies demonstrated the presence of a cell population with the peculiar GCDC phenotype in FL biopsies and a similar localization of these cells inside tumoral and reactive follicles. Therefore, we analyzed the relationships between GCDC and the other cell subsets of the tumor follicles. Some of CD4+ and CD8+ T lymphocytes present inside the follicle were found to be in close association with GCDC, suggesting a potential implication of GCDC in their activation. In addition, the distribution of GCDC inside FL and reactive follicles did not appear disrupted, in contrast to follicular dendritic cells, the other follicle dendritic cell type. Finally, we demonstrated that GCDC could be detected from FL lymph node cell suspension by flow cytometry. Taken together, these results indicate that FL development is not associated with a disappearance of GCDC or with a lack of physical interactions between GCDC and T cells inside the follicles. In addition, the fact that GCDC can be observed in FL samples by flow cytometry should allow their purification to further study their putative role in FL development and maintenance.

Cytokines in the evolution and treatment of AIDS-lymphoma

AIDS-lymphoma is a heterogeneous disease that most likely results from the complex interaction of several contributing factors, including chronic antigenic activation of B lymphocytes, dysregulated cytokine and co-stimulatory networks, infection with potentially oncogenic viruses (human herpesvirus-8 [HHV-8], Epstein-Barr virus), and accumulation of secondary genetic mutations. Cytokines are believed to play an important role in the immunologic decline that favors opportunistic infection and malignancy in advanced HIV infection. Recent work has provided some evidence that cytokine therapy can partially reverse the immune dysregulation seen in AIDS. This suggests that cytokines are likely to have an important role in both the pathogenesis and treatment or prevention of AIDS-lymphoma.

Practical applications of immunohistochemistry in hematolymphoid neoplasms

Immunohistochemistry plays a key role in the diagnosis and classification of hematolymphoid neoplasms. New cell and lineage markers are constantly being discovered and added to the existing long list of antibodies. In this review article we provide general information and new applications of the commonly used hematolymphoid markers. We also discuss the features and applications of some newly discovered markers, such as ALK, fascin, granzyme/perforin, and tryptase. There is no universal "panel" for the diagnosis of hematolymphoid neoplasms. However, in this review article, we provide suggested panels for a given hematolymphoid neoplasm that is based on our experience and that reported in the literature.

Serum levels of soluble vascular cell adhesion molecule-1 (sVCAM-1) are elevated in advanced stages of non-Hodgkin's lymphomas

The serum levels of soluble vascular cell adhesion molecule-1 (sVCAM-1) were measured in 116 patients with non-Hodgkin's lymphomas (NHL) tested previously for soluble intercellular adhesion molecule-1 (sICAM-1). In contrast to Hodgkin's disease and chronic lymphocytic leukaemia, the sVCAM-1 levels in NHL patients were not significantly different from the levels of healthy controls (n = 31). However, sVCAM-1 was elevated in advanced stage disease, i.e. stages III + IV. Elevated serum levels of sVCAM-1 were associated with significantly poorer disease-free (p = 0.024) and overall (p = 0.02) survival. sVCAM-1 correlated poorly with other known prognostic variables (LDH, sTK and beta 2m) and with sICAM-1. None of the tested markers added prognostic information for disease-free survival independently of Ann Arbor stage and B-symptoms. The expression of VCAM-1 and ICAM-1 in tumour biopsies from 15 patients representing 7 different histologies were examined and compared with the serum levels of the soluble adhesion molecules. No correlation was found between the adhesion molecule expression by vascular endothelium and the corresponding serum levels.

Serum levels of soluble vascular cell adhesion molecule-1 (sVCAM-1) are elevated in advanced stages of non-Hodgkin's lymphomas

The serum levels of soluble vascular cell adhesion molecule-1 (sVCAM-1) were measured in 116 patients with non-Hodgkin's lymphomas (NHL) tested previously for soluble intercellular adhesion molecule-1 (sICAM-1). In contrast to Hodgkin's disease and chronic lymphocytic leukaemia, the sVCAM-1 levels in NHL patients were not significantly different from the levels of healthy controls (n=31). However, sVCAM-1 was elevated in advanced stage disease, i.e. stages III+IV. Elevated serum levels of sVCAM-1 were associated with significantly poorer disease-free (p = 0.024) and overall (p = 0.02) survival. sVCAM-1 correlated poorly with other known prognostic variables (LDH, sTK and beta2m) and with sICAM-1. None of the tested markers added prognostic information for disease-free survival independently of Ann Arbor stage and B-symptoms. The expression of VCAM-1 and ICAM-1 in tumour biopsies from 15 patients representing 7 different histologies were examined and compared with the serum levels of the soluble adhesion molecules. No correlation was found between the adhesion molecule expression by vascular endothelium and the corresponding serum levels.

Prognostic value of follicular dendritic cells in nodular sclerosing Hodgkin's disease

AIMS

In nodular sclerosing Hodgkin's disease (NSHD), the prognostic relevance of the histopathological grading in two subtypes NSI (low-grade) and NSII (high-grade) remains controversial. Analysis of follicular dendritic cells (FDC) may provide new prognostic parameters.

METHODS AND RESULTS

Tumours from 59 patients with NSHD were studied. Mean follow-up time was 8 years. Forty-one cases were classified as NSI and 18 as NSII. FDC were immunostained with the paraffin-resistant monoclonal antibodies CD21 and CNA.42. We distinguished three patterns in the neoplastic tissue: FDC1, the presence of well-defined follicle-like structures (n = 20); FDC2, the presence of largely destroyed FDC networks (n = 25); and FDC3, no or a few isolated FDC (n = 14). The three groups differed clearly regarding the frequency of relapse and the survival. The longest survival was seen in the FDC1 group, the shortest in the FDC3 group, the FDC2 group being intermediate (P = 0.0025). FDC status was a discriminating prognostic factor for all patients, and within various age and stage categories. Combining the FDC status and the NSI-NSII grading defined the best survival group as FDC1-NSI.

CONCLUSIONS

Assessment of FDC pattern, associated with histological subtyping, brings valuable data for predicting survival and outcome in NSHD.

Human T lymphocytes bind to germinal centers of human tonsils via integrin alpha4/VCAM-1 and LFA-1/ICAM-1 and -2

Binding of T lymphocytes within the different compartments of the secondary lymphoid organs is crucial for the function of the cellular and the humoral immune response. It is still not known which adhesion molecules guide T cells to the distinct areas of the lymphoid microenvironment. In the current study an in situ adhesion assay was used to define the receptors for binding of T cells to human tonsils. The T cell lines Jurkat and MOLT-4 and normal, activated T cells were found to bind exclusively to germinal centers. Jurkat cells used the receptor pair integrin-alpha4 (VLA-4alpha)/VCAM-1, whereas activated MOLT-4 cells and normal T cells bound via both adhesion pathways, namely via integrin-alpha4/VCAM-1 and LFA-1/ICAM-1 and -2. It is suggested that these adhesion mechanisms are involved in the migration of T cells into the germinal centers of secondary lymphoid organs and that they influence the selection of B cells by apoptosis.