Mechanisms of human lymphocyte migration and their role in the pathogenesis of disease

Cutaneous Lymphoma and Antibody-Directed Therapies

The introduction of monoclonal antibodies such as rituximab to the treatment of cancer has greatly advanced the treatment scenario in onco-hematology. However, the response to these agents may be limited by insufficient efficacy or resistance. Antibody–drug conjugates are an attractive strategy to deliver payloads of toxicity or radiation with high selectivity toward malignant targets and limited unwanted effects. Primary cutaneous lymphomas are a heterogeneous group of disorders and a current area of unmet need in dermato-oncology due to the limited options available for advanced cases. This review briefly summarizes our current understanding of T and B cell lymphomagenesis, with a focus on recognized molecular alterations that may provide investigative therapeutic targets. The authors reviewed antibody-directed therapies investigated in the setting of lymphoma: this term includes a broad spectrum of approaches, from antibody–drug conjugates such as brentuximab vedotin, to bi-specific antibodies, antibody combinations, antibody-conjugated nanotherapeutics, radioimmunotherapy and, finally, photoimmunotherapy with specific antibody–photoadsorber conjugates, as an attractive strategy in development for the future management of cutaneous lymphoma.

Pure abscopal effect of radiotherapy in a salivary gland carcinoma: Case report, literature review, and a search for new approaches

We report the case of an 84-year-old woman with poorly differentiated non-small cell carcinoma of the right parotid who presented with headache, was found to have a primary right parotid gland cancer as well as metastatic disease, and underwent palliative radiotherapy to the primary site. The patient received no chemotherapy or immunotherapy, but both the primary site and several non-irradiated foci in the lungs regressed or completely resolved. The patient remained free of disease for about one year before progression. The case is a rare instance of abscopal regression of metastatic disease in the absence of pharmacologic immunomodulation. A literature review surveys the history of the abscopal effect of radiation therapy, attempts to understand the mechanisms of its successes and failures, and points to new approaches that can inform and improve the outcomes of radioimmunotherapy.

Mechanisms of LtxA (Leukotoxin), a Potent New Anti-Inflammatory Agent for the Treatment of Alopecia Areata

Alopecia areata is an autoimmune condition where activated, pro-inflammatory white blood cells (WBCs) attack the hair follicles, resulting in hair loss. Migration of these activated WBCs from the blood stream and into the follicle tissue requires interaction between the integrin, lymphocyte function-associated antigen-1 (LFA-1) on WBCs, and ICAM-1 on vascular endothelial cells. High levels of active LFA-1 are uniquely expressed on WBCs that are involved in autoimmune and inflammatory conditions. The natural biologic agent LtxA (Leukothera) preferentially targets and depletes disease activated and malignant WBCs by binding to active LFA-1. The experimental drug has demonstrated significant therapeutic efficacy against autoimmune/inflammatory conditions such as psoriasis and allergic asthma in mouse models for these diseases. In addition, when injected into rodents, rhesus macaques, and dogs, LtxA was demonstrated to be physiologically active, biologically specific, and extremely well-tolerated. LFA-1 is an attractive target for therapy because it is only normally present on WBCs and has been shown to be activated and overexpressed on WBCs that are responsible for autoimmune/inflammatory conditions.

Differential expression of cell adhesion molecules in the functional compartments of lymph nodes and tonsils

Aims-To analyse the topographical distribution of adhesion molecules involved in lymphocyte recirculation in human lymph nodes and tonsils. The study focused on the expression of LECAM-1 (CD62L), VLA-alpha4 (CD49d), VLA-beta1 (CD29), LFA-1 alphaL (CD11a), LFA-beta2 (CD18), VCAM-1 (CD106), ICAM-1 (CD54), and H-CAM (CD44).Methods-Reactive lymph nodes and palatine tonsils were studied using immunofluorescence methods with fluorescein isothiocyanate (FITC) labelled monoclonal antibodies directed against cell adhesion molecules. To investigate the expression patterns of these molecules in the T and B cell populations, double labelling experiments were performed using Texas Red labelled antibodies against CD2 or CD19, respectively. The images from each fluorochrome were then simultaneously analysed using a laser scanning confocal microscope.Results-LECAM-1, VLA-alpha4 and H-CAM were predominantly expressed by mantle zone B cells, VCAM-1 and ICAM-1 by germinal centre cells, most of which exhibited a reticular staining pattern suggestive of follicular dendritic cells, whereas LFA-1 alphaL and LFA-beta2 were mainly found in extrafollicular and germinal centre T cells. All high endothelial venules expressed VLA-beta1 and ICAM-1, whereas VCAM-1 was present in only a few, with variable intensity.Conclusions-The data show that all of these adhesion molecules are differentially distributed within the distinct functional microenvironments of both organs. The differences observed in the expression patterns among the B and T cells belonging to different compartments probably depend on the momentum of cell traffic, the stage of maturation/activation, as well as on their functional role in the immune response.

Lymphoma dissemination: the other face of lymphocyte homing

The orchestration of systemic immune responses is critically dependent on coordinated lymphocyte migration and recirculation. This "homing" guides lymphocytes to the microenvironments that control their differentiation and survival, disperses the immunologic repertoire, and targets effector lymphocytes to sites of antigenic insult. Lymphocyte homing is a multistep process that requires chemotaxis and cell adhesion coupled with strategies to overcome physical barriers. At the molecular level, it is regulated by adhesion molecules and chemokines, and facilitated by intrinsic molecular programs that allow "ameboid" shape change, allowing highly effective lymphocyte traffic between different tissue compartments. In case of malignant transformation, however, the fact that lymphocytes are "licensed to move" forms a serious threat to the organism, because it permits rapid tumor dissemination irrespective of the conventional anatomic boundaries limiting early spread in most types of cancer. Thus, unlike the metastatic spread of other cancers, lymphoma dissemination generally is not a reflection of tumor progression but of conserved physiological behavior. The dissemination patterns often reflect basic rules of lymphocyte homing, explaining the strikingly tissue-specific dissemination of, for example, mucosal lymphomas, cutaneous lymphomas, and multiple myeloma. Understanding the molecular mechanisms underlying this behavior may provide novel targets for treatment of lymphoma patients.

Gastrointestinal lymphoproliferative disorders

Malignant lymphomas can be first detected in some patients in endoscopic biopsies of the gastrointestinal (GI) tract. However, their recognition and accurate classification often pose problems for the pathologist for several reasons. First, the small sampling size limits pattern recognition and the number of ancillary studies which can be performed. Second, the immune system of the GI tract is capable of intense hyperplastic responses which may mimic lymphoma. Third, in a fashion similar to cutaneous lesions, those in the alimentary tract may be visualized and biopsied at a very early phase in their development when differentiation into neoplasia may be incomplete. Some forms of immune response actually pass through a poorly defined transition into lymphoma. Examples of such 'dysplasia' of the gut immune system include Helicobacter gastritis, coeliac disease and multicentric lymphoid hyperplasia associated with underlying immunodeficiency. With ever increasing endoscopic scrutiny of the gut by gastroenterologists, it is not surprising that the frequency of these indeterminate cases seems to be growing. In combination with careful clinical correlation and conventional microscopic analysis, selective immunohistochemical studies currently constitute the most powerful ancillary method in the pathologist's effort to recognize and classify GI lymphomas accurately.

Adhesion of B cell lines to endothelial cells from human lymphoid tissue modulates tyrosine phosphorylation and endothelial cell activation

Through the production of cytokines and growth factors the endothelium of secondary lymphoid organs plays a crucial role in controlling lymphocyte migration to the lymphoid microenvironment, an essential step in the initiation of the immune response. Here we demonstrate that direct contact of B cell lines with tonsil-derived human endothelial cells resulted in changes in the phosphorylation state of endothelial cells, causing their functional activation. We found a rapid (<15-s) and transient dephosphorylation, followed by a rapid rephosphorylation of tyrosine residues of the focal adhesion kinase, paxillin, and ERK2. Maximal rephosphorylation occurred after 15-30 min of B cell contact. Preincubation of lymphoid B cells with an adhesion-blocking Ab directed against alpha(4)beta(1) integrin abrogated adhesion-mediated changes of endothelial cell tyrosine phosphorylation, suggesting that cell contact was essential. Similar patterns of tyrosine phosphorylation, but with slightly different kinetics were induced after cross-linking of beta(1) integrin or CD40 on endothelial cells. Functional activation of endothelial cells by B cell adhesion was confirmed by the production of IL-6, IL-8, monocyte chemoattractant protein-1, M-CSF, and macrophage inflammatory protein-1beta mRNA. However, direct cross-linking of beta(1) integrin and CD40 failed to accomplish the same functional activation. These data indicate that direct contact of lymphoid B cells with the endothelium from lymphoid tissue induce endothelial cell signaling, resulting in chemokine and cytokine production. This phenomenon may provide a mechanism for the remodeling of the endothelium from lymphoid tissues, thus contributing to the free migration of lymphocytes and other cells into the lymphoid organs.

Monoclonal antibody against beta7 integrins, but not beta7 deficiency, attenuates intestinal allograft rejection in mice

BACKGROUND

beta7 integrins mediate homing and retention of lymphocytes to the normal and inflamed small bowel in a tissue-selective fashion. In the present study, we investigated the expression of beta7 integrins after small bowel transplantation (SBT) and tested the effects of blocking beta7-mediated pathways by using monoclonal antibody (mAb) or knockout mice.

METHODS

Heterotopic SBT from BALB/c to C57BL/6 (B6) was used as a surgical model. Expression of beta7 integrins was measured on recipient lymphocytes (CD4 and CD8 ) in spleen, blood, and mesenteric lymph nodes (MLN) using flow cytometry. To analyze the effects of blocking beta7 integrins on graft survival, either beta7-deficient B6 or wild-type B6 mice that were treated with mAb against beta7 were studied.

RESULTS

After allogeneic SBT, there were markedly increased levels of alpha4beta7 recipient CD8 lymphocytes in MLN, blood, and spleen as early as 3 days postoperatively. In contrast, alpha4beta7 integrin levels in isograft recipients were similar to those of normal mice. Mean survival time of intestinal allografts was not affected by beta7 deficiency (7.3+/-1 days) compared with wild-type mice (7.5+/-0.8 days). However, mAb against beta7 integrins significantly prolonged graft survival (12.8+/-1 days) compared with treatment with control mAb (7.3+/-1 days, <0.001). Histologic changes of SBT rejection were significantly attenuated when mice were given mAb against beta7.

CONCLUSION

As indicated by the increased levels of alpha4beta7 CD8 lymphocytes, activation of this integrin contributes to the immune response in SBT rejection. Furthermore, blocking beta7 integrins with mAb provides a suitable target for immunosuppressive therapy. The discrepancy in survival data obtained by mAb and beta7 deficiency may be a result of the more rapid activation of compensatory mechanisms in the knockout mice.

Cell adhesion receptors in lymphoma dissemination

Regulated lymphocyte trafficking is essential for the control and integration of systemic immune responses. This homing process disperses the immunologic repertoire, guides lymphocyte subsets to the specialized microenvironments that control their differentiation and survival, and targets immune effector cells to sites of antigenic insult. This review discusses data indicating that the adhesion receptors regulating the trafficking of normal lymphocytes are also expressed and functionally active in their malignant counterparts, the non-Hodgkin lymphomas. These “homing receptors” appear to mediate the highly tissue-specific dissemination of specific lymphoma subtypes, such as lymphomas of the mucosa-associated lymphoid tissues and lymphomas of the skin. Furthermore, as a result of their capability to enhance lymphoma dissemination and to transduce signals into the cell, promoting cell growth and survival, adhesion receptors may contribute to lymphoma aggressiveness. Taken together, the data offer a framework for understanding the dissemination routes of non-Hodgkin lymphomas and suggest that adhesion receptors, specifically those of the CD44 family, may present useful tools to predict prognosis in patients with lymphomas.

Ocular adnexal lymphoma-comparison of MALT lymphoma with other histological types

AIMS

To correlate histological features of ocular adnexal lymphoma using the revised European American lymphoma classification (REAL), with stage of disease at presentation, treatment modalities, and patient outcome. MALT lymphoma defines an extranodal marginal zone B cell lymphoma as outlined in the REAL classification. Comparison groups of patients included those with primary ocular adnexal MALT lymphoma versus primary ocular adnexal lymphomas of other types, MALT lymphoma versus non-MALT lymphomas (primary and secondary), and primary ocular adnexal lymphoma (MALT lymphomas and other types) versus secondary ocular adnexal lymphomas.

METHODS

A retrospective review of the National Ophthalmic Pathology Laboratory records identified 20 cases of ocular adnexal lymphoma over a 10 year period which were reclassified using appropriate immunohistochemical stains. Patients' medical records were examined for data including stage of the disease at presentation, mode of treatment, and patient outcome.

RESULTS

Among the 20 cases identified 14 had primary ocular adnexal lymphomas. 10 of the primary lymphomas had histological features of MALT lymphoma. One case was a primary ocular adnexal T cell lymphoma, one a follicular centre, follicular B cell lymphoma, and two were large cell B cell lymphomas. Six cases had systemic disease, four large B cell, one follicular centre, follicular B cell, and one mantle cell. A significantly higher proportion of patients with MALT lymphomas had early disease (p = 0.005), initially required local treatment (p = 0.005) and were alive at last follow up (p = 0.001) than those without. Two patients with MALT lymphoma had recurrence of lymphoma which responded to further treatment.

CONCLUSIONS

Patients with primary ocular adnexal MALT lymphomas present with localised disease requiring local treatment and have a better outcome compared with patients with other types. As a small percentage of these tumours recur, patients should be followed up indefinitely.

Radiological appearances of lymphomas arising from mucosa-associated lymphoid tissue (MALT) in the lung

We review the radiological findings in 13 patients with histologically proven (n = 10) or clinically diagnosed (n = 3) lymphomas arising in mucosa-associated lymphoid tissue (MALT) of the lung. These rare B-cell lymphomas typically follow an indolent course, and many cases are still being incorrectly described in current radiological literature under the term pseudolymphoma. The patients frequently give a history of autoimmune disease involving the affected organ, and involvement of another mucosal site as part of a disseminated MALT lymphoma, is common. The radiographic patterns of pulmonary parenchymal involvement in lung MALT lymphomas have been reviewed, and correlation made with their clinical behaviour.

Altered Tumor Growth and Metastasis of a T-Cell Lymphoma in Timp-1 Transgenic Mice

The concept of tumor suppression by tissue inhibitor of metalloproteinases (TIMPs) has evolved primarily from studies of genetically modulated tumor cells. The next step is to focus on the host and assess the protective potential of host TIMP-1 on primary tumor growth and metastasis. We generated two transgenic mouse lines with altered Timp-1 expression in skin and liver: one overexpressed Timp-1 (Timp-1high), and the other had antisense RNA–mediated Timp-1 reduction (Timp-1low). ESbL-lacZ T-lymphoma cells provided the tumor challenge, as they form primary tumors upon intradermal injection with spontaneous metastasis to liver. Metastases were examined in X-Gal–stained whole-organ mounts. Timp-1 overexpression inhibited intradermal tumor growth and spontaneous metastasis, leading to prolonged survival of the mice. The opposite effects occurred in Timp-1low mice, leading to shorter host survival. Experimental metastasis assays showed that Timp-1–compromised livers in Timp-1low mice showed at least a doubling of metastatic foci and numerous additional micrometastases, indicative of increased host susceptibility. However, Timp-1high mouse livers showed an unaltered metastatic load in the experimental metastasis assay. In conclusion, these data demonstrate that Timp-1 levels within a tissue predetermine the development and progression of T-cell lymphoma.

Metastatic potential of lymphoma/leukemia cell lines in SCID mice is closely related to expression of CD44

To investigate whether the lymphocyte homing receptors, adhesion molecules regulating normal lymphocyte traffic, influence the dissemination of lymphoma cells, 24 lymphoma/leukemia cell lines were inoculated into SCID mice subcutaneously, and the correlation between the expression of the adhesion molecules and the metastatic potential of the cell lines was examined. Among the six adhesion molecules examined (LFA-1, ICAM-1, CLA, VLA-4, L-selectin and CD44), L-selectin increased the incidence of lymph node metastasis, and CD44 expression was related to both lymph node and organ (hematogenous) metastasis. A monoclonal antibody to the standard form of CD44 (CD44s), Hermes-3, inhibited the local growth and remote metastasis of CD44+ cell lines. Thus, it is concluded that at least CD44s expression is important in both lymphatic and hematogenous metastasis.

Progression in gastric carcinoma relative to the ratio of CD44 epithelial variant transcript to CD44 hematopoietic variant transcript

BACKGROUND

It has been suggested that CD44 splice variants play a role in the progression of certain epithelial cancers and non-Hodgkin's lymphoma. In this study, we investigated the epithelial variant/hematopoietic variant (E/H) ratio (the amount of the CD44 epithelial variant transcript relative to the CD44 hematopoietic variant transcript) in human gastric carcinoma compared with normal gastric mucosa.

METHODS

The ratio was determined for tumors and adjacent noncancerous mucosa from 30 gastric carcinoma patients using reverse transcription-polymerase chain reaction and Southern blotting. We also determined the tumor (T)E/H--noncancerous mucosa (N)E/H (the difference between E/H ratios of tumor tissue and adjacent noncancerous mucosa) and examined these measurements for correlations with the pathologic features of gastric carcinoma, as well as for their usefulness as an indicator of tumor progression.

RESULTS

The E/H ratio in tumor tissue was significantly higher than in adjacent noncancerous mucosa (P < 0.01). The TE/H--NE/H in patients with lymph node metastases was 0.16 +/- 0.11, compared with 0.07 +/- 0.08 in cases without lymph node metastases (P < 0.05). Significant correlations also were observed between the TE/H--NE/H and the depth of invasion, blood vessel invasion, and lymphatic vessel invasion (P < 0.03, P < 0.03, and P < 0.01, respectively).

CONCLUSIONS

Our results suggest that increases in the E/H ratio may be a useful indicator of progression in gastric carcinoma.

Lymphoma in Sjögren's syndrome. From histopathology to molecular pathology

A number of autoimmune diseases predispose to the development of neoplasia. A particularly well-recognized association is the development of lymphoma in Sjögren's syndrome. Although this risk has been estimated to be 44 times that of the general population, few reliable prognostic indexes exist for individual patients. Recent advances in molecular biology have improved our understanding of Sjögren's syndrome and permitted better characterization of the generalized lymphoproliferation associated with the condition. This article reviews the histopathology of the major and minor salivary gland lesions of Sjögren's syndrome and discusses advances in molecular biology that have permitted more accurate prediction of lymphoma development in this group of patients.

Progression in gastric carcinoma relative to the ratio of CD44 epithelial variant transcript to CD44 hematopoietic variant transcript

BACKGROUND

It has been suggested that CD44 splice variants play a role in the progression of certain epithelial cancers and non-Hodgkin's lymphoma. In this study, we investigated the epithelial variant/hematopoietic variant (E/H) ratio (the amount of the CD44 epithelial variant transcript relative to the CD44 hematopoietic variant transcript) in human gastric carcinoma compared with normal gastric mucosa.

METHODS

The ratio was determined for tumors and adjacent noncancerous mucosa from 30 gastric carcinoma patients using reverse transcription-polymerase chain reaction and Southern blotting. We also determined the tumor (T)E/H--noncancerous mucosa (N)E/H (the difference between E/H ratios of tumor tissue and adjacent noncancerous mucosa) and examined these measurements for correlations with the pathologic features of gastric carcinoma, as well as for their usefulness as an indicator of tumor progression.

RESULTS

The E/H ratio in tumor tissue was significantly higher than in adjacent noncancerous mucosa (P < 0.01). The TE/H--NE/H in patients with lymph node metastases was 0.16 +/- 0.11, compared with 0.07 +/- 0.08 in cases without lymph node metastases (P < 0.05). Significant correlations also were observed between the TE/H--NE/H and the depth of invasion, blood vessel invasion, and lymphatic vessel invasion (P < 0.03, P < 0.03, and P < 0.01, respectively).

CONCLUSIONS

Our results suggest that increases in the E/H ratio may be a useful indicator of progression in gastric carcinoma.

Nasal T-cell lymphoma: a clinicopathological and immunophenotypic analysis of 13 cases

Thirteen cases of nasal lymphomas with T-cell or natural killer (NK)-cell phenotype were studied, with attention to clinical presentation and follow-up, the presence of Epstein-Barr virus (EBV) using in situ hybridization (EBER), the immunophenotype, and the presence of cytotoxic granules. All but two patients presented with stage I disease. In three cases local progression resulted in involvement of the central nervous system. When dissemination occurred, this was predominantly to extranodal localizations, in two cases to the skin. Response to therapy was highly variable, but patients treated with radiotherapy with or without additional chemotherapy had a better prognosis than patients treated with initial chemotherapy alone. All lymphomas were associated with EBV, and most cases showed cytotoxic features, ten of which were CD56 positive. In eight cases a T-cell origin was proven, but in five cases a possible NK-cell origin could not be excluded. No clinical differences were seen between true T-cell lymphomas and possible NK-cell neoplasms. Nasal T-cell lymphomas should be considered as a distinct clinicopathological entity, strongly associated with EBV, and with cytotoxic features in most cases. No prognostic parameters were detected to predict dissemination and response to therapy.

Expression on leukemic cells and serum circulating levels of intercellular adhesion molecule-1 (ICAM-1) in B-cell chronic lymphocytic leukemia: implications for prognosis

Expression of intercellular adhesion molecule-1 (ICAM-1) has been correlated clinical and laboratory characteristics of 62 patients with untreated CD5+ chronic lymphocytic leukemia (CLL). ICAM-1 was detected on B-CLL cells from 19 out of 62 patients (30.6%) and its expression did not correlate with the majority of immunological markers. An important finding of this study was the association between ICAM-1 expression and mean fluorescence intensity (MFI) of Slg (r = 0.507; P < 0.001). As far as correlation with clinical parameters is concerned, a statistically significant association between Binet clinical stages and ICAM-1 expression was found (P < 0.05). Furthermore, an atypical CLL morphology was more frequently encountered among patients who expressed ICAM-1 (P < 0.005). To obtain more information on the role of ICAM-1 in CLL we measured serum levels with a sandwich enzyme immunoassay. In 47 B-cell CLL patients studied, the mean value of circulating ICAM-1 levels was significantly higher (561 +/- 201 ng/ml) than that observed in 25 normal controls (353 +/- 162 ng/ml; P < 0.005); a clear correlation being found with Binet clinical stages (P = 0.026) and bone marrow (BM) histology (P < 0.005). We conclude that circulating ICAM-1 is elevated in CLL and such an increase reflects tumor mass as defined by clinical stages and BM histology, rather than peripheral blood lymphocytosis (r = 0.240). Even if soluble ICAM-1 appears to be less specifically increased that soluble CD23 serum levels, these circulating molecules were not completely independent of each other (r = 0.512; P < 0.001).

Epstein-Barr virus (EBV) in extranodal T-cell non-Hodgkin's lymphomas (T-NHL). Identification of nasal T-NHL as a distinct clinicopathological entity associated with EBV

T-cell Non-Hodgkin's lymphomas (T-NHL) can be defined as clonal malignant proliferations related phenotypically and functionally to normal T-cell populations of the lymphoid tissue. There is increasing evidence that T-NHL with similar morphology but originating from different sites differ in their clinical behaviour, immunophenotypic features, oncogene expression and relation with oncogenic viruses such as HTLV-I and EBV. Indeed, it has been shown that the prevalence of EBV in T-NHL is related to the site of origin. Thus, EBV was found in nearly all nasal T-NHL but only in a proportion of primary nodal, lung, gastrointestinal and Waldeyer's ring T-NHL while it was undetectable in most primary cutaneous T-NHL. Besides their constant association with EBV, nasal T-NHL display peculiar clinical, histological, immunophenotypic and genotypic features. They present clinically as lethal midline granuloma and histologically as pleomorphic malignant tumours variably associated with angiocentricity, angioinvasion and necrosis. Moreover, they frequently exhibit extensive loss of T-cell antigens, including CD3 and TCR alpha beta and gamma delta proteins, usually express the Natural Killer (NK)-related CD56 antigen and frequently show absence of clonal rearrangements of TCR beta, gamma and delta loci. Therefore, among T-NHL, nasal T-NHL can be regarded as a distinct clinicopathologic entity associated with EBV, which could be derived either from immature T-cells or from NK cells.

In vivo dynamic MRI tracking of rat T-cells labeled with superparamagnetic iron-oxide particles

Dynamic MRI tracking of rat T-cells in vivo is performed in rat testicles after labeling isolated rat T-cells in vitro with superparamagnetic dextran-coated iron-oxide particles, BMS180549. Tissue inflammation induced by the local injection of the calcium ionophore, A23187, is used to attract labeled T-cells. Gradient-echo MR images of rat testicles show a statistically significant decrease (4%) of the signal intensity in areas of injection of A23187 as early as 30 min after intravenous infusion of 2 x 10(8) labeled T-cells. The signal change reaches its maximum (6-7% decrease) at about 60-120 min after cell infusion. T2-mapping also shows a decrease of T2 in the areas with A23187. Image quantitation, which includes a chemical-shift effect, significantly enhances the sensitivity for detection of superparamagnetically labeled T-cells. Localization of labeled T-cells in rat testicles has been verified by fluorescence microscopy studies of T-cells co-labeled with a lipophilic fluorescent carbocyanine dye, 1,1-dioctadecyl-3,3,3',3'-tetramethyl-lindocarbocyanine perchlorate. These results represent the first successful demonstration of dynamic tracking of specific cells in vivo using MRI.

Peripheral B lymphocyte repertoire to mitochondrial antigen in primary biliary cirrhosis--positive correlation between the disease activity and the frequency of circulating B lymphocytes specific for pyruvate dehydrogenase complex

B lymphocytes committed to the production of IgG antibodies (Abs) to mitochondrial antigen such as pyruvate dehydrogenase complex(PDC) were quantitated in the peripheral blood of patients with primary biliary cirrhosis(PBC) using Epstein-Barr virus as a polyclonal activator of human B lymphocytes. B lymphocytes committed to the production of IgG Abs to PDC were found in high frequency in patients with PBC(0.54 +/- 0.16%, mean value +/- SE, of total IgG-producing B lymphocytes) in contrast to type C chronic hepatitis and healthy subjects in which they were less than 0.01%. The frequency of these B lymphocytes specific for PDC increased in parallel to the progression of the Scheuer's stage from I to II (stage I: 0.35 +/- 0.23%, stage II: 1.04 +/- 0.32%), but decreased with further progression to stage IV (stage III: 0.39 +/- 0.21%, stage IV: 0.07 +/- 0.06%). In addition, B lymphocytes specific for PDC decreased in the peripheral blood during the administration of cyclosporin A; this was accompanied by an improvement of lymphocyte infiltration severity in the liver. These data indicate that B lymphocytes specific for PDC are present in the peripheral blood of patients with PBC and their frequency reflects the degree of the lymphocyte infiltration in the liver.

The binding of acute myeloid leukemia blast cells to human endothelium

AML blast cell adhesion to endothelium is in all likelihood a prerequisite for blast cell migration across the vascular wall in the periphery and the subsequent establishment of leukemic extravascular disease. A general feature of malignant cells is their acquisition of altered or aberrant adhesive capabilities which appear to be associated with their ability to metastasize. Aberrant expression of integrin adhesion molecules and of membrane oligosaccharide structures is found in AML and various solid tumors. With respect to AML, these alterations in adhesive phenotype may confer a proliferative advantage on the malignant cells in the marrow, may facilitate egress from the bone marrow into the peripheral vasculature and may enable AML blast cells to traverse the vessel wall and so establish extravascular disease. Oncogenes may be directly involved in the acquisition of such aberrant adhesive phenotypes. Neutrophil extravasation is described as a model for leukocyte migration across the vessel wall and brief summaries of experimental work involving aspects of AML blast cell and normal CD34+ bone marrow cell adhesion to endothelium in vitro are described.

Expression of the mucosal homing receptor alpha 4 beta 7 in malignant lymphomatous polyposis of the intestine

Recent studies have identified the integrin alpha 4 beta 7 as a mucosal homing receptor that mediates lymphocyte migration to the intestinal mucosa by binding to MAd-CAM-1, which is a vascular recognition molecule (adressin) selectively expressed on mucosal endothelium. The expression of the alpha 4 beta 7 mucosal homing receptor was studied in eight cases of malignant lymphomatous polyposis (MLP). This unusual presentation of non-Hodgkin's lymphoma of mantle cell type is characterized by multifocal lymphomatous involvement of the gastrointestinal tract. Unlike nodal mantle cell lymphomas, cases of MLP showed expression of alpha 4 beta 7, suggesting that this homing receptor plays an important role in determining the characteristic mucosal dissemination pattern of MLP.

Classification of primary cutaneous T-cell lymphomas

The term cutaneous T-cell lymphoma designates a group of neoplasms of skin homing T-cells that show considerable variation in clinical presentation, histological appearances, immunophenotype and prognosis. The disadvantages of currently available histological classification schemes are discussed and a new classification is presented. This is based on a combination of clinical, histological and immunophenotypic criteria and it recognizes distinct clinico-pathological entities within this group of diseases.

The migration of bone marrow cells to thymic culture supernatants is inhibited by stress

The effect of immobilization stress on precursor cell migration from bone marrow to the thymus was studied in C57BL/6 mice. The in vitro migration assays, using Nucleopore chambers, showed that precursor cell migration to thymus supernatants was strongly inhibited in stressed animals. This inhibition of migration seemed to be cell-associated what can explain the thymic involution observed in mice under stress conditions. The migration of precursor cells from bone marrow may be one of the mechanisms by which the thymus gland is involuted by stress.

Disseminated growth of Hodgkin's-derived cell lines L540 and L540cy in immune-deficient SCID mice

Local tumor growth has been reported after subcutaneous and intraperitoneal injection of Hodgkin's disease (HD) derived cell lines into different immunodeficient mouse strains. An animal model with disseminated growth of tumor cells would be useful for studying the in vivo biology of HD cells as well as for preclinical testing of new therapeutic regimens. For this purpose the HD-derived cell lines L540, L540cy, L428, and KM-H2 were injected intravenously into SCID mice. In contrast to L428 and KM-H2, widespread neoplasia occurred after a period of four to six weeks following injection of L540 and the subline L540cy. Lymph nodes were found to be the preferred site of tumor growth. CD30 surface antigen expression on Hodgkin cells and the karyotype of the tumor cells were preserved in the animal host. Thus, to a large extent, the SCID mouse model mimics the dissemination pattern of Hodgkin's disease in man. To evaluate the role of adhesion molecule expression in the dissemination of HD-derived cell lines, CD44 and members of the immunoglobulin, integrin, selectin, and Fc receptor families were quantified by flow cytometry. CD30 expression was also measured. Although CD44 expression has been correlated with dissemination in non-Hodgkin's lymphoma (NHL), this was not the case in the Hodgkin's SCID mouse model. CD44 was not expressed on the disseminating cell lines L540 and L540cy but was expressed in the nondisseminating lines L428 and KM-H2.

Distribution of saccharides in pig lymph-node high-endothelial venules and associated lymphocytes visualized using fluorescent lectins and confocal microscopy

The distribution of saccharides in pig lymph nodes, particularly on high-endothelial venule (HEV) endothelium and on lymphocytes in these vessels, was studied by examining the binding of fluorescent conjugates of 18 different lectins. Eight of the lectins, particularly with glycan specificity restricted to mannose and polyacetyllactosamine determinants, were found to bind with a high affinity to these structures. Competitive inhibition experiments revealed that polylactosamine-containing glycans were present on endothelia and lymphocytes using lectins from Lycopersicon esculentum and Solanum tuberosum, the latter lectin reacting with lymphocytes only when apparently adherent to the luminal endothelium. The The absence on pig endothelium of the Ulex europaeus binding, shown by human endothelia due to the presence of certain fucose epitopes, was confirmed. Pig lymph-node endothelium, however, bound the fucose-specific lectin of Tetragonolobus purpureas, indicating the presence of fucose on pig endothelia in a different conformation to that seen on human endothelia. The results suggested that pig lymph-node HEV endothelium expressed a core fucosylated tri- or tetra-antennary complex glycan with polylactosamine extensions and expressing an Ley determinant.

CD44 splice variants: metastases meet lymphocytes

Recent discoveries of surface proteins involved in tumor metastasis formation have revived an old hypothesis that tumor cells may acquire, and use for their metastatic spreading, properties which lymphoid cells had developed to defend the organism against foreign antigens. Splice variants of CD44 and integrins are expressed on metastasizing tumor cells and also on leukocytes at defined stages of their differentiation. Expression and function appear to be essential not only for the generation of an immune response but also for the establishment of metastatic tumor colonies.

Lymphocyte-endothelial interactions in inflamed synovia: involvement of several adhesion molecules and integrin epitopes

The role of several adhesion molecules for lymphocyte-endothelial interactions in the synovia of rheumatoid arthritis patients was studied using the frozen section assay. Partial inhibition of lymphocyte binding to endothelium of synovial sections could be observed with antibodies against CD44, L-selectin, and beta 1- and beta 2-integrins, pointing to the participation of several adhesion molecules in the regulation of lymphocyte immigration into inflamed synovia rather than the presence of a unique homing receptor. Different degrees of inhibition were found within a series of antibodies against alpha 4- and beta 1-integrins known to have functional effects in other interaction systems. In addition, increased binding to endothelial cells was induced when lymphocytes were pretreated with TS2/16 anti-beta 1 IgG, whereas binding to non-endothelial components of synovia was increased after treatment with HP 2/4 (anti-alpha 4) Fab. The data suggest a multifunctional role of alpha 4/beta 1-integrins in directly mediating adhesion as well as regulating adhesive interactions in the rheumatoid synovia.

Differential expression of cell adhesion molecules in B-zone small lymphocytic lymphoma and other well-differentiated lymphocytic disorders

BACKGROUND

Cell adhesion molecules (CAM) may determine the patterns of growth and dissemination of lymphoproliferative disorders.

METHODS

The authors have studied, by flow cytometric and immunohistochemical examination, the expression of several CAM, mediating cell-cell and cell-microenvironment interactions, on B-zone small lymphocytic lymphoma (BZSLL) and other B-cell low-grade non-Hodgkin lymphomas (NHL), including intermediate lymphocytic/mantle zone lymphoma (ILL/MZL), small lymphocytic lymphoma (SLL), and chronic lymphocytic leukemia (CLL).

RESULTS

Relevant differences in the "adhesion phenotype" of BZSLL compared with other low-grade NHL examined were evidenced. Cells from BZSLL displayed a higher rate of expression and/or a stronger intensity of LFA-1, LFA-3, ICAM-1, and BL-CAM and a lower density of H-CAM and LAM-1 homing receptors, as opposed to SLL or CLL. A lower intensity of H-CAM along with a stronger expression of LFA-1, LFA-3, ICAM-1, and BL-CAM were also detected by comparing BZSLL with ILL/MZL: Malignant cells from BZSLL expressed Leu-CAMb determinants in three cases. BZSLL cells lacked VLA-alpha 5-integrins as opposed to CLL lymphocytes and displayed a stronger reactivity with anti-VLA-alpha 4 antibodies with respect to ILL/MZL and CLL. beta 1-integrins were consistently detected on BZSLL lymphocytes as opposed to ILL/MZL:

CONCLUSIONS

These data suggest that the adhesion phenotype of BZSLL, by favoring homotypic and heterotypic adhesive interactions of tumor cells, might account at least in part for the peculiar intranodal compartmentalization leading to a deceptively benign (reactive) histologic appearance, and for the smoldering clinical course of this lymphoma. The pattern of CAM expression detected by the authors on malignant lymphocytes also is suggestive for a cellular origin of BZSLL from a rare subset of interfollicular or external mantle B-lymphocytes.

Binding of an SJL T cell clone specific for myelin basic protein to SJL brain microvessel endothelial cells is inhibited by anti-VLA-4 or its ligand, anti-vascular cell adhesion molecule 1 antibody

Adhesion molecules probably are required for the migration of T lymphocytes to inflamed tissues, but the roles of these molecules have yet to be understood in the pathogenesis of inflammatory diseases such as multiple sclerosis. The adhesion of an SJL murine T cell clone specific for myelin basic protein (MBP) to endothelial cells (ECs) from SJL newborn brain microvessels was examined. Sixty percent of the 2 x 10(4) T cell clones stimulated once every 2 weeks with MBP were bound to ECs, whereas less than 5% of the same number of lymphocytes from peripheral lymph nodes were bound. However, binding was not central nervous system (CNS)-specific. Monoclonal antibody to VLA-4 or VCAM-1 partially inhibited the binding of the T cell clone to ECs. Binding of the T cell clone to ECs increased when the latter were incubated with IL-1 or TNF, but was not inhibited by anti-VLA-4 or VCAM-1. We suggest that the VLA-4/VCAM-1 pathway functions in the binding of the T cell clone specific for MBP to brain ECs but that adhesion molecules other than VLA-4/VCAM-1 are involved because anti-VLA-4 and anti-VCAM-1 did not produce complete inhibition.

Monoclonal antibody 4C7 recognizes an endothelial basement membrane component that is selectively expressed in capillaries of lymphoid follicles

In order to define compartment-related structures within the extracellular matrix of human lymphoid organs, monoclonal antibodies (MAbs) were generated by immunizing mice with stromal fragments of human tonsils. One MAb (4C7) was selected which recognized an endothelial basal membrane component that is selectively expressed in capillaries of lymphoid follicles. The epitope was also present in follicles within chronically inflamed synovial membrane and in a hyperplastic thymus of a patient with myasthenia gravis. B-cell non-Hodgkin's lymphomas with a follicular growth pattern expressed the antigen in neoplastic follicles, whereas diffuse growing lymphomas lacked the antigen. The restricted distribution pattern suggests involvement of the 4C7-defined antigen in the organization of the follicular compartment within human lymphoid tissue.

Skin-homing T lymphocytes: detection of cutaneous lymphocyte-associated antigen (CLA) by HECA-452 in normal human skin

The immigration of circulating T cells into specific tissues is directed by the interaction between adhesion molecules on lymphocyte subpopulations and their ligands on vascular endothelium. Of these, endothelial leucocyte adhesion molecule (ELAM-1), weakly expressed in normal human skin (NHS), seems to be the counter-structure for cutaneous lymphocyte-associated antigen (CLA). CLA is a 200 kDa cell-surface glycoprotein of which the sugar moieties sialyl Le(a) and sialyl Le(x) are the possible epitopes recognized by the monoclonal antibody HECA-452. HECA-452 was originally described as a marker for lymphoid organ high endothelial cells, but 16% of peripheral-blood-derived T cells react with this antibody. We studied the expression of CLA on the cellular constituents of the skin immune system (SIS). By applying immunohistochemical double staining, 41% of CD3+ T cells, 44% of CD4+ T cells and 31% of CD8+ T cells were found to express CLA. Keratinocytes, CD1a+ Langerhans cells (LC) and endothelial cells did not express HECA-452 in significant numbers in NHS. Monocytes were found to express HECA-452 in 14% of CD68+ cells. CLA expression was present on a relatively low percentage of T cells and subsets localized distant from NHS vessels, suggesting loss of the molecule during further migration after transendothelial passage. However, intraepidermal T cells expressed CLA in similar percentages to T cells localized directly perivascularly. Our findings support the notion that CLA expression by T cells is associated with their homing into cutaneous structures.

Identical expression of ELAM-1, VCAM-1, and ICAM-1 in sarcoidosis and usual interstitial pneumonitis

Extravasation of leucocytes in tissues is mediated by leucocyte-endothelial cell interactions in which adhesion molecules play an important role. Until now, two pathways have been unravelled, i.e., the LFA-1/ICAM-1 and the VLA-4/VCAM-1 pathways. ELAM-1 has been shown to be involved in granulocyte accumulation and recently also in lymphocyte migration. The role of HECA-452 is under investigation. In this study we have investigated the expression of the above-mentioned adhesion molecules in lung tissue of patients with pulmonary sarcoidosis and usual interstitial pneumonitis (UIP), and in mediastinal lymph nodes of patients with sarcoidosis. ICAM-1 (CD54) was broadly distributed on the endothelium of all the vessels found in sarcoidosis and UIP. VCAM-1 was present on the endothelium of the venules, capillaries, and arterioles in both sarcoidosis and UIP. ELAM-1 reacted with endothelial cells lining venules and capillaries in chronic progressive sarcoidosis and in the active phase of UIP but not in the stationary phases of both diseases. HECA-452 activity could be detected only on high endothelial venules within sarcoid lymph nodes. In lung tissues, macrophages bearing the ICAM-1 antigen were present in sarcoid tissue but not in the interstitium and alveolar space of UIP. LFA-1 (CD11a/CD18) and VLA-4 (CD49d/CD29) were present on all leucocytes found but seemed to be more highly expressed on lymphocytes in sarcoidosis. These findings suggest that the LFA-1/ICAM-1 and VLA-4/VCAM-1 pathways are involved in leucocyte migration in both types of lung disease, while in the active phases of sarcoidosis and UIP, ELAM-1 is also involved.

Splanchnic nerve stimulation increases the lymphocyte output in mesenteric efferent lymph

Mesenteric efferent lymph was collected from anaesthetized sheep. Lymph flow rate and leucocyte content (> 95% lymphocytes) were measured under control conditions and during stimulation of the left greater splanchnic nerve. During the first 5 min of nerve stimulation at 4 Hz lymph flow was increased by 128 +/- 57% and lymph white cell count by 44 +/- 15% (P < 0.05, n = 8 in both cases). This produced an overall increase in the white cell output of 228 +/- 151% (P < 0.05, n = 8). The response was repeatable but short lived, with no significant differences from control being observed after the first 5 min of stimulation. There was a rise in the red cell count in arterial blood during nerve stimulation (from 3.21 +/- 0.24 x 10(12) l-1 to 4.48 +/- 0.22 x 10(12) l-1, P < 0.05, n = 9) but no statistically significant changes in the white cell count or percentage of lymphocytes. The increase in lymph white cell output could be mimicked by intravenous injection of noradrenaline while phentolamine blocked the nerve-induced increases in both lymph flow and white cell concentration. The possible mechanisms and immunological consequences of this alpha-adrenoceptor-mediated increase in lymphocyte traffic are discussed.

Lymphocyte subsets recirculate from blood to lymph at different rates in conscious sheep

Lymphocytes migrate and recirculate continuously between blood and lymph. The current study compared the migratory properties of lymphocyte subsets by labelling lymphocyte surface antigens and analysing simultaneous samples of mesenteric lymph, systemic arterial blood and mesenteric venous blood from conscious sheep. The lymphocyte output in lymph averaged 5.33 +/- 0.89 x 10(6) min-1 (lymph flow rate of 92 +/- 13 microliters min-1, lymphocyte count 61.9 +/- 10.7 x 10(9) l-1, n = 10) and the proportion of cells which carried the CD4 antigen (CD4+) was considerably higher in lymph (46 +/- 3%) than in arterial blood (23 +/- 2%; p < 0.01, n = 9). This increase was paralleled by a small but statistically significant decrease in the percentage of CD4+ cells in mesenteric venous blood (20 +/- 2%), as compared with systemic arterial blood (26 +/- 2%; p < 0.05, n = 6), which is consistent with the hypothesis that CD4+ cells migrate out of the blood vessels, and recirculate through the lymphatics, more readily than other lymphocyte subsets.

Expression of cell adhesion molecules in the salivary and lacrimal glands of Sjogren's syndrome

We attempted to determine whether cell adhesion molecules, including vascular cell adhesion molecule-1 (VCAM-1), intercellular adhesion molecule-1 (ICAM-1), and E-selectin (endothelial-leukocyte adhesion molecule-1; ELAM-1), are involved in the lymphoid cell infiltration of the salivary and lacrimal glands in Sjogren's syndrome (SS) patients. Both immunohistochemical analysis and the reverse-transcripts polymerase chain reaction (RT-PCR) were used to analyze the expression of VCAM-1, ICAM-1, ELAM-1, very late antigen 4 (VLA-4 [alpha 4,beta 1]), lymphocyte function-associated antigen-1 (LFA-1), interferon-gamma (IFN-gamma), tumor necrosis factor (TNF), and interleukin-1 beta (IL-1 beta). Immunohistochemical analysis of salivary gland biopsies from SS patients showed a marked expression of VCAM-1 and ICAM-1 in the venules surrounded by infiltrated CD4+ CD45RO+ T cells. E-selectin was expressed on vascular endothelium with weak intensity. Increased levels of VCAM-1, ICAM-1, IFN-gamma, and IL-1 beta mRNA were demonstrated by RT-PCR, whereas E-selectin mRNA were weakly expressed in SS lacrimal and salivary gland tissues. This is in contrast with strong expression of ELAM-1 in IL-1 beta-stimulated human umbilical vascular endothelial cells (HUVEC) in vitro. Cytokine-mediated up-regulation of VCAM-1 and ICAM-1 that facilitates the recruitment of VLA-4 and LFA-1 expressing T cells might contribute to lymphoid cell infiltration in the salivary and lacrimal glands in SS.

Establishment and characteristics of a T-cell acute lymphoblastic leukemia cell line, JK-T1, with a chromosomal translocation between 8q24 and 14q13

A human leukemia cell line, JK-T1, was established from the bone marrow of a 10-year-old boy with T-cell acute lymphoblastic leukemia. The origin of the leukemic cell line, JK-T1, was demonstrated by its chromosomal and immunologic similarity to the patient's fresh leukemic cells. Karyotypic analysis revealed 46,XY,del(6)(q?),t(8;14)(q24;q13),der(9)t(9;?)(q34;?). In JK-T1, neither rearrangement nor amplification of the c-myc gene was observed apparently because the breakpoint of chromosome 14 was not q11 but q13. JK-T1 was independent of interleukin 2 (IL-2) because of little production of IL-2, little IL-2 receptor (CD25) on the surface, and no response to exogenous IL-2. JK-T1 had lymphocyte function associated antigen-1 (LFA-1) (CD11a, CD18) on its surface and could adhere to the hematologic stromal layer. These characteristics of JK-T1 cell line are considered to be useful not only for evaluating the role of t(8;14) but also in studying the adhesion molecules of leukemia.

Differential expression of the HECA-452 antigen (cutaneous lymphocyte associated antigen, CLA) in cutaneous and non-cutaneous T-cell lymphomas

The monoclonal antibody HECA-452 identifies an antigen that is primarily expressed on high endothelial venules, the preferred site of lymphocyte extravasation in lymphoid tissues, and also on a subpopulation of myelomonocytic cells and some T-cells. We investigated the expression of the HECA-452 antigen, also called the cutaneous lymphocyte associated antigen, in primary cutaneous and primary non-cutaneous T-cell non-Hodgkin's lymphomas. The tumour cells of cutaneous T-cell non-Hodgkin's lymphomas were positive in 53% of cases, while only 5% of the non-cutaneous lymphomas were positive. These differences were also present in morphologically identical tumours. Thus, the tumour cells in six out of 10 primary cutaneous anaplastic large cell T-cell lymphomas were positive, while they were positive in none of 24 primary non-cutaneous anaplastic large cell T-cell lymphomas. In general, primary cutaneous and primary nasal T-cell non-Hodgkin's lymphomas were devoid of HECA-452 positive high endothelial venules, whereas most nodal T-cell non-Hodgkin's lymphomas contained HECA-452 positive high endothelial venules. These observations suggest that the HECA-452 antigen might be related to a skin-associated type of lymphoid tissue and to lymphomas originating in the skin. However, the results of HECA-452 expression in secondary sites, and the clinical data of the primary cutaneous large cell lymphomas did not support the concept that HECA-452 is functionally involved in homing to the skin, or that loss of the HECA-452 antigen is related to tumour progression of primary cutaneous T-cell lymphomas.(ABSTRACT TRUNCATED AT 250 WORDS)

Lymphocyte migration to tumors after hyperthermia and immunotherapy

We have previously shown that the combination of immunotherapy with interleukin 2 (IL-2) and local hyperthermia (LHT) abrogates the growth of murine subcutaneous tumors significantly more than either modality alone. This study was undertaken to investigate whether the beneficial effect of combined modality therapy could be attributed to increased trafficking of effector cells to the tumor. After inducing MCA-105 sarcomas in the hindlimbs of C57BL/6 mice, animals were given no therapy, LHT, IL-2, or IL-2 + LHT followed by an iv injection of 51Cr-labeled syngeneic splenocytes or LAK cells. Select organs and the tumor-bearing extremity were counted in a gamma counter. IL-2 or LHT alone did not affect lymphocyte migration, while IL-2 + LHT significantly decreased trafficking (P less than 0.001) to the tumor. LAK cells showed increased migration to the tumor site compared to splenocytes in all treatment groups (P less than 0.02). IL-2 caused increased migration of LAK cells but not splenocytes to the lung; this was not affected by LHT. LAK cell trafficking to the spleen was decreased by IL-2 and IL-2 + LHT, while splenocyte migration was decreased in the LHT and combined treatment groups. LHT and IL-2 had no effect on trafficking of either effector cell type to liver or kidney. These results show that the beneficial effect of combined modality therapy may not be due to increased trafficking of lymphocytes to the tumor area. In addition, LAK cells traffic more to subcutaneous tumors than splenocytes, and this cannot be explained by the differential trafficking to other organs. The results of this study will be important in the planning of future experiments with combined adoptive immunotherapy and hyperthermia.