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Immunophenotype of lymphocytic infiltration in medullary carcinoma of the breast.

Medullary carcinoma (MC) of the breast is characterized by large anaplastic cells and infiltration by benign lymphocytes. Patients with this pattern of breast carcinoma are considered to have a better prognosis than those with other histological subtypes. We reviewed cases of primary breast carcinoma that were surgically resected between 1990 and 2004. Of these, 13 cases of medullary carcinoma of the breast with lymphocyte infiltration were reported. Tests for CD3, CD4, CD8, CD20, CD56, TIA-1, and granzyme B were performed on paraffin sections. We found that the MC contained very few NK cells, as assessed by their reactivity with the CD56 antibodies. However, MC had a significantly greater percentage of CD3, CD8, TIA-1, and granzyme B lymphocytes infiltrating the stroma of the tumor. Furthermore, more CD8-positive than CD4-positive T-cell lymphocytes were present within the tumor cell nests in MC, as opposed to the proportion in usual ductal carcinoma. The infiltrating cytotoxic/suppressor T cells in MC represent host resistance against cancer, and the high grading of the T-cell infiltration could explain, in part, a key mechanism controlling the good prognosis for this type of tumor and solve the pathological paradox of MC.

Breast Neoplasms↗

Organotypic culture of HPV-transformed keratinocytes: a model for testing lymphocyte infiltration of (pre)neoplastic lesions of the uterine cervix.

The aim of our study was to establish the relevance of an in vitro model for analysing the ability of human lymphocytes to infiltrate human papillomavirus (HPV)-associated (pre)neoplastic lesions of the uterine cervix. To mimic these lesions, we have used the organotypic raft culture of HPV-transformed keratinocytes (SiHa). The SiHa organotypic raft culture was co-cultured with resting or prestimulated (IL-2 or IL-2+anti-CD3 mAb) allogeneic peripheral blood mononuclear cells (PBMC) for 24 and 72 h. The majority of infiltrating cells were T lymphocytes. Occasional NK cells were also identified. The stimulation with IL-2+anti-CD3 mAb induced the highest number of infiltrating cells, with the maximum lymphocyte infiltration observed after 24 h of co-culture. The lymphocyte infiltration was associated with an increased number of apoptotic cells in the organotypic cultures. The ability of PBMC and purified T cell and NK cell populations to lyse HPV-transformed keratinocytes was also investigated on monolayer cultures. As expected in an allogenic model, the highest cytotoxicity was mediated by NK cells activated by IL-2 or IL-2+anti-CD3 mAb. The cytotoxic activity of T cells was weak but, interestingly, increased in the presence of phytohaemagglutinin A (PHA), assuming that T cells were able to kill HPV-infected keratinocytes when a bridge between T cells and keratinocytes was provided. In conclusion, the organotypic culture of HPV-transformed keratinocytes may provide an effective in vitro model for investigating novel T cell-based immunotherapy protocols for the treatment of HPV-associated lesions.

Antibodies, Monoclonal↗

Tumor infiltration by myeloid suppressor cells in response to T cell activation in rat gliomas.

We have recently reported that activation of tumor-specific T cells by subcutaneous vaccination with irradiated T9 glioma cells of syngeneic rats with a pre-existing, intracranial (i.c.) T9 glioma (T9+vaccination) promotes the mobilization of myeloid suppressor cells (MSC) which inhibit T cell function resulting in unregulated tumor progression. The current study investigated if this immunological paradigm could be recapitulated in T cell deficient rats, in other rat glioma models or using a dendritic cell (DC) vaccine. When nude rats were used in the T9+vaccination model, the level of MSC tumor infiltration remained low in vaccinated and control groups and there was no significant difference in tumor size between the groups. Increased tumor infiltration by MSC after vaccination with respective irradiated tumor cells was observed in the 9L, F98 and D74 gliomas. RT-2 tumors were markedly infiltrated with MSC regardless of vaccination. Enhanced tumor progression in response to immunization and T cell activation was observed in rats bearing F98 and D74 gliomas, although less pronounced than in the T9 model, and there was a trend for increased tumor size in the 9L glioma model. Increased MSC infiltrate and augmented T9 glioma growth were observed when DC pulsed with T9 cell lysate was used as a vaccine. These results suggest that MSC infiltration and unregulated tumor growth in response to vaccination is T cell-dependent; is not unique to the T9 glioma; and can be recapitulated with an alternate immunization approach.

Animals↗

The course of allergen-induced leukocyte infiltration in human and experimental asthma.

BACKGROUND: Although the timing of allergen-induced bronchoconstriction is well defined, there is little information about the kinetics of allergen-induced leukocyte infiltration in asthma and its comparability between human and animal models of asthma. OBJECTIVE: To investigate systematically allergen-induced leukocyte infiltration into the airway lumen in human and experimental asthma by using bronchoalveolar lavage. METHODS: Patients with allergic asthma were lavaged at different time points as long as 1 week after segmental allergen challenge. Allergen-sensitized mice were lavaged as long as 3 weeks after allergen challenge. Differential cell counts, lymphocyte subsets, and cytokines were assessed in bronchoalveolar lavage fluid. RESULTS: In both models, neutrophil infiltration was a relatively early event (maximum: 18 hours after challenge). In contrast, eosinophil infiltration peaked 42 hours (human model) to 4 days (mouse model) after allergen challenge, paralleled by an IL-5 peak in this period. There were elevated macrophage counts over a period of several days after allergen challenge in both models. Lymphocytes (predominantly CD4+ T cells) peaked 18 hours after challenge in the human model, but not until 2 weeks after challenge in the murine model. CONCLUSION: Early neutrophil accumulation (within hours after challenge) and delayed eosinophil accumulation (within days after challenge) in the airway lumen are common features of allergen-induced airway inflammation, whereas lymphocyte kinetics are dependent on the asthma model. CLINICAL IMPLICATIONS: Similarities in the infiltration kinetics of granulocytes after allergen challenge suggest a common role for these cells in asthma, whereas the presumed orchestration of allergic inflammation by lymphocytes appears to differ between the models.

Adult↗

Tumour lymphocytic infiltrate and recurrence of hepatocellular carcinoma following liver transplantation.

BACKGROUND/AIMS: Liver transplantation is an effective treatment for highly selected patients with hepatocellular carcinoma (HCC), but tumour recurrence remains an important cause of mortality. There are few data on the relation between the recurrence of HCC and lymphocytic infiltration following liver transplantation. METHODS: The tumour CD4+, CD8+, CD25+ and Foxp3+ lymphocyte infiltrate was assessed by immunohistochemistry in explant tissue of 69 patients who underwent liver transplantation for HCC between 1985 and 2001. The data were analysed according to HCC recurrence and factors known to be associated with outcome. RESULTS: Tumour size (Hazard ratio (95% CI: 1.19 (1.02, 1.39), P = 0.03)), vascular invasion (P = 0.02), lymphocyte infiltration (P = 0.02) and CD4:CD8 ratio (P = 0.001) were identified as significant univariate predictors of tumour recurrence. On multivariate analysis CD4:8 ratio (P = 0.001), vascular invasion (P = 0.01), tumour size (P = 0.06) and reduced lymphocyte infiltration (P = 0.03) were significant independent predictors of recurrence. The presence of Foxp3+ T-lymphocytes was not predictive of recurrence, but was associated with vascular invasion (FE = 9.02, P = 0.04). CONCLUSIONS: The data support the hypothesis that immune responses are important in HCC and that the phenotype of infiltrating lymphocytes is informative regarding prognosis.

CD4-CD8 Ratio↗

HLA class I expression and tumor immune infiltration together shape colon cancer immune contexture.

BACKGROUND: The relative contribution of HLA class I molecules-including classical HLA class Ia (HLA-A, -B, -C) and non-classical HLA class Ib (HLA-E, -F, -G)-to shaping the tumor immune microenvironment in colon cancer remains insufficiently defined. We investigated how their expression patterns relate to immune infiltration and clinical outcome. METHODS: In a retrospective cohort of 280 colon cancers, we assessed HLA class Ia and class Ib expression and quantified CD45-positive immune cell infiltration by immunohistochemistry. These features were correlated with clinicopathological variables, microsatellite instability (MSI) status, and previously established genomic immune signatures. RESULTS: High HLA class Ia expression and increased CD45-positive cell infiltration were each associated with improved overall, disease-specific, and progression-free survival. CD45-positive density correlated strongly with Immunologic Constant of Rejection scores. HLA class Ia loss was more frequent in advanced stages and in MSI-H tumors. Among HLA class Ib molecules, only HLA-E expression was associated with favorable disease-specific and progression-free survival. Integrative analysis identified three immune phenotypes with distinct prognostic profiles; tumors characterized by high HLA class Ia expression, low HLA class Ib expression, and high CD45-positive infiltration had the best outcomes. CONCLUSION: Colon cancer immunogenicity is shaped by coordinated patterns of HLA class I expression and immune infiltration. Integrating HLA class Ia/Ib expression with immune cell density provides a refined stratification of tumor immune phenotypes and may support personalized immunotherapeutic decision-making.

Antigen presentation↗

Role of osteopontin in hepatic neutrophil infiltration during alcoholic steatohepatitis.

Alcoholic liver disease (ALD) is a major complication of heavy alcohol (EtOH) drinking and is characterized by three progressive stages of pathology: steatosis, steatohepatitis, and fibrosis/cirrhosis. Alcoholic steatosis (AS) is the initial stage of ALD and consists of fat accumulation in the liver accompanied by minimal liver injury. AS is known to render the hepatocytes increasingly sensitive to toxicants such as bacterial endotoxin (LPS). Alcoholic steatohepatitis (ASH), the second and rate-limiting step in the progression of ALD, is characterized by hepatic fat accumulation, neutrophil infiltration, and neutrophil-mediated parenchymal injury. However, the pathogenesis of ASH is poorly defined. It has been theorized that the pathogenesis of ASH involves interaction of increased circulating levels of LPS with hepatocytes being rendered highly sensitive to LPS due to heavy EtOH consumption. We hypothesize that osteopontin (OPN), a matricellular protein (MCP), plays an important role in the hepatic neutrophil recruitment due to its enhanced expression during the early phase of ALD (AS and ASH). To study the role of OPN in the pathogenesis of ASH, we induced AS in male Sprague-Dawley rats by feeding EtOH-containing Lieber-DeCarli liquid diet for 6 weeks. AS rats experienced extensive fat accumulation and minimal liver injury. Moderate induction in OPN was observed in AS group. ASH was induced by feeding male Sprague-Dawley rats EtOH-containing Lieber-DeCarli liquid diet for 6 weeks followed by LPS injection. The ASH rats had substantial neutrophil infiltration, coagulative oncotic necrosis, and developed higher liver injury. Significant increases in the hepatic and circulating levels of OPN was observed in the ASH rats. Higher levels of the active, thrombin-cleaved form of OPN in the liver in ASH group correlated remarkably with hepatic neutrophil infiltration. Finally, correlative studies between OPN and hepatic neutrophil infiltration was corroborated in a simple rat peritoneal model where enhanced peritoneal fluid neutrophil infiltration was noted in rats injected OPN intraperitoneally. Taken together these data indicate that OPN expression induced during ASH may play a significant role in the pathogenesis of ASH by stimulating neutrophil transmigration.

Animals↗

Infiltration of neutrophils is required for acquisition of metastatic phenotype of benign murine fibrosarcoma cells: implication of inflammation-associated carcinogenesis and tumor progression.

QR-32 tumor cells, a clone derived from a murine fibrosarcoma, are poorly tumorigenic and nonmetastatic when injected into syngeneic C57BL/6 mice. However, they are converted to highly malignant ones once they have grown in vivo after being co-implanted in a subcutaneous site with a foreign body, a gelatin sponge. Early phase of inflammation induced by the gelatin sponge participates in the conversion and histological analysis shows predominant infiltration of neutrophils. The objective of this study was to determine whether the depletion of the infiltrating neutrophils has any effect on the tumor progression. Intraperitoneal administration of a monoclonal anti-granulocyte antibody, RB6-8C5 (RB6), depleted neutrophils from both the peripheral blood circulation and the local inflamed site in mice with co-implantation of QR-32 tumor cells and gelatin sponge. The RB6 administration did not inhibit either tumor development or growth of QR-32 tumor cells. In contrast, tumor cell lines established from RB6-administered mice showed a significant decrease in metastatic incidence as compared with the tumor cell lines obtained from the mice with administration of control rat IgG or saline. Metastatic ability was significantly suppressed when RB6 had been administered in the early phase (from day -2 to day 6 after implantation); however, the administration in the middle (from day 6 to day 14) or late (from day 14 to day 22) phase did not affect the metastatic ability. We confirmed the phenomena by using integrin beta(2) knockout mice that had impaired neutrophil infiltration into inflamed sites. In the knockout mice, neutrophils hardly infiltrated into the gelatin sponge and the tumors showed dramatically suppressed metastatic phenotype as compared with those in wild-type mice or nude mice. Immunohistochemical analysis demonstrated that expressions of 8-hydroxy-2'-deoxyguanosine and nitrotyrosine were parallel to those in the presence of neutrophils. These results suggested that inflammation, especially when neutrophils infiltrate into tumor tissue, is primarily important for benign tumor cells to acquire metastatic phenotype.

8-Hydroxy-2'-Deoxyguanosine↗

A minor E-selectin ligand, CD65, is critical for extravascular infiltration of acute myeloid leukemia cells.

Adhesive ligands on acute myeloid leukemic (AML) blasts may mediate transmigration and extravascular infiltration. In this study, 30 AML samples were examined for expression and density of adhesion antigens. By univariate analysis, four patients with extravascular infiltration showed significantly higher expression of CD2, CD11a, CD11b, CD11c, CD15, CD65, CD86, and HLA-DR as compared with patients without infiltration. These four patients also showed significantly higher density of CD11a, CD11b, CD11c, CD15 and CD65 expression. By multivariate analysis, CD65 expression was the only significant independent risk factor for infiltration, suggesting that this is a critical adhesion molecule for extravascular AML infiltration.

Acute Disease↗

Mechanisms and roles of neutrophil infiltration in stress-induced gastric injury in rats.

Water-immersion and restraint stress is associated with an increase in neutrophil infiltration into the gastric mucosa, but the mechanism responsible for this infiltration is unclear. We investigated the involvement of intercellular adhesion molecule-1 (ICAM-1) and tumor necrosis factor-alpha (TNF-alpha) in neutrophil infiltration in stress-induced gastric injury in rats. Rats were administered neutralizing antibody against ICAM-1 or TNF-alpha and were subjected to induction of gastric injury by 6-hr water-immersion and restraint stress. To evaluate the relationship between gastric acid and neutrophil infiltration, some rats were given cimetidine before administration of stress. Neutralizing antibodies inhibited both the lesion formation and the increase in myeloperoxidase activity induced by stress. Expression of ICAM-1 on endothelial cells was increased by stress, accompanied by an increase of TNF-alpha-positive cells. Antibody against TNF-alpha inhibited this increase in ICAM-1 expression. Cimetidine almost completely inhibited gastric lesions, but did not affect myeloperoxidase activity. In conclusion, neutrophil infiltration in stress-induced gastric injury may be mediated by ICAM-1 and TNF-alpha, but not gastric acid, and may play crucial roles in the progression of gastric injury.

Animals↗

Involvement of MIP-2 and CXCR2 in neutrophil infiltration following injection of late apoptotic cells into the peritoneal cavity.

Apoptotic cells are cleared by phagocytes, such as macrophages, as soon as they appear in vivo. If apoptosis occurs acutely, however, macrophages may be outnumbered by apoptotic cells, which causes late apoptosis. We previously showed that injection of late apoptotic cells into the peritoneal cavity led to transient infiltration of neutrophils. In this study, we examined the involvement of MIP-2 and CXCR2 in the neutrophil infiltration. We first produced a recombinant MIP-2 protein, and a fusion protein between CXCR2 and GST in E. coli, and then generated anti-MIP-2 antibodies and anti-CXCR2 antibodies in rabbits. We then confirmed their specificity by Western blotting analysis and flow cytometry. Injection of late apoptotic cells, such as P388 cells treated with etoposide for 24 hours and CTLL-2 cells cultured in IL-2-free medium for 28 hours, induced neutrophil infiltration into the peritoneal cavity, as expected. The antibodies, but not control antibodies against GST, suppressed the neutrophil infiltration to the level caused by injection of normal (viable) cells, suggesting that MIP-2 and CXCR2 are mainly involved in the neutrophil infiltration caused by late apoptotic cells.

Animals↗

Automated kappa and lambda light chain mRNA expression for the assessment of B-cell clonality in cutaneous B-cell infiltrates: its utility and diagnostic application.

INTRODUCTION: Primary cutaneous B-cell lymphoma (1 degrees CBCL) accounts for 25% of all lymphomas. The difficulty in distinction of reactive from neoplastic B-cell infiltrates prompts the use of molecular diagnostic adjuncts. While T-cell clonality can be seen in various reactive states, clonal B-cell infiltrates are often neoplastic; standard assays employed include polymerase chain reaction (PCR) or Southern blot analysis to assess heavy chain rearrangement. We sought to assess the utility of kappa (kappa) and lambda (lambda) mRNA expression using the Ventana automated assay (Ventana Medical Systems, Tucson, AZ, USA) in the analysis of atypical cutaneous B-cell lymphoid infiltrates. MATERIALS AND METHODS: Multiple 4 micro m sections of paraffin-embedded, formalin-fixed skin biopsies from 31 patients with CBCL were placed on silane-coated slides, deparaffinized, then digested in pepsin (5 mg/ml) for 30 min at 37 degrees C. Fluorescein-tagged oligoprobes and tissue mRNA were denatured at 80 degrees C for 5 min, hybridized for 2 h at 37 degrees C, and incubated with antifluorescein alkaline phosphatase conjugates. Detection of the probe target complex employed nitroblue tetrazolium and bromochloroindolyl phosphate conjugates with a nuclear fast red counterstain. A kappa : lambda ratio > 3 : 1 was held to represent kappa light chain restriction and a kappa : lambda ratio </= 1 : 1 to indicate lambda light chain restriction. RESULTS: The diagnosis in each case was determined by careful integration of clinical, histologic, and phenotypic data. The diagnoses included: pseudolymphoma (PL), marginal zone lymphoma (MZL), 1 degrees CBCL of the trunk, scalp or leg, 2 degrees lymphoma, and plasma cell dyscrasia. All but one case of lymphoma were light chain restricted. All cases of PL were proven to be polyclonal by this methodology. In non-plasmacytic small cell lymphomas, only 5-10% of the infiltrate expressed kappa or lambda, with clonality established through the abnormal kappa : lambda ratio. Interpretations were most difficult in the 2 degrees small cell-dominant follicular center cell lymphomas and easiest in cases with significant plasmacytic differentiation (i.e. MZL, immunocytomas, or plasma cell dyscrasias). CONCLUSION: The Ventana kappa/lambda assay is a reliable, quick, and inexpensive way to determine B-cell clonality in cutaneous lymphoid infiltrates in paraffin-embedded formalin-fixed tissue.

B-Lymphocytes↗

Heterogeneity of T-cell clones infiltrating primary malignant melanomas.

It is established that primary malignant melanomas (pMM) can be infiltrated by T-cell populations with predominantly one T-cell clone. As pMM generally express multiple tumor-associated antigens (TAA), here we used laser-capture microdissection (LCM) to isolate different tumor-infiltrating lymphocyte (TIL) clusters in order to determine whether pMM are infiltrated only by one single clone or whether the TAA may attract various T-cell populations. As T-cell receptor (TCR) clonality is a useful tool for the demonstration of specific T-cell clones, we analyzed 56 pMM, three cutaneous melanoma metastases, and 15 pairs of pMM with a sentinel lymph node (SLN) for clonal rearrangements of the (TCR) gamma chain gene. We detected the clonality of TCR gamma chain gene in 25 of 56 pMM, and in 10 of 17 SLN studied. In four of the 15 pairs of primary tumor and SLN, we found clonal TCR gamma in both the melanoma and the SLN, with two pairs harboring the identical clone. As we detected different clones in pMM and the corresponding SLN, we subsequently performed LCM in 21 malignant melanomas with multiple lymphocytic clusters for the presence of focal clonal T cells in different regions of the melanoma. In seven melanomas, both clusters of TILs showed the same rearranged TCR gamma chain gene and in five of the seven biopsies the clonal rearrangement occurred in different variable (V) regions of the TCR gamma chain gene. These tumors showed infiltration by more than one clone. In 10 biopsies TCR clonality was restricted to one cluster, while the second microdissected sample of the infiltrate was polyclonal. In conclusion, within one primary malignant melanoma several T-cell clones with different rearrangements may occur. The balance between these clones may decide on the progress of melanoma.

Clone Cells↗

High expression of the chemokine receptor CXCR4 predicts extramedullary organ infiltration in childhood acute lymphoblastic leukaemia.

Childhood acute lymphoblastic leukaemia (ALL) is a malignancy with the potential to infiltrate the liver, spleen, lymph nodes and brain. Such extramedullary presentation is important for understanding the biology of childhood ALL and also for developing new prognostic parameters. A potential mechanism in the trafficking of leukaemia cells is the interaction of the chemokine receptor CXCR4, which is expressed on ALL cells, and its ligand stromal cell-derived factor-1 (SDF-1), produced by stromal cells in bone marrow and extramedullary organs. Functionality of CXCR4 was demonstrated by a high correlation between cell surface density of CXCR4 and transendothelial migration of leukaemia blasts towards a gradient of SDF-1 (r = 0.73, P = 0.001). Inhibition of SDF-1-induced migration by an anti-CXCR4 monoclonal antibody (78.33 +/- 23.86% inhibition) evidenced the specificity of CXCR4 to SDF-1. In order to evaluate clinical significance of CXCR4 expression, lymphoblasts from the bone marrow of 73 patients with and without extramedullary organ infiltration were compared. Multiparameter flow cytometry revealed that lymphoblasts from patients with high extramedullary organ infiltration, defined as ultrasonographically measured enlargement of liver or spleen, expressed the CXCR4 receptor at higher fluorescence intensity (median 66.12 +/- 66.17) than patients without extramedullary organ infiltration (median 17.56 +/- 19.29; P < 0.001). Consequently, high expression of CXCR4 was strongly predictive for extramedullary organ involvement, independently of the peripheral lymphoblast count. Highest CXCR4 expression was seen in mature B ALL (median 102.74 +/- 92.13; P < 0.003), a disease characterized by a high incidence of extramedullary bulky disease. As high expression of the chemokine receptor CXCR4 predicts extramedullary organ infiltration in childhood ALL, we suggest that CXCR4 and its ligand play an essential role in extramedullary invasion.

Antibodies, Monoclonal↗

Leukaemic pulmonary infiltrates in adult acute myeloid leukaemia: a high-resolution computerized tomography study.

Leukaemic infiltration of the lungs may occur in acute myeloid leukaemia (AML). Pulmonary infiltrates are usually microscopic and invariably associated with hyperleucocytosis. Four AML patients with respiratory symptoms and low leucocyte counts underwent standard chest radiography, bronchoscopy with bronchoalveolar lavage and high-resolution computerized tomography (HRCT) of the lungs. HRCT scans showed pulmonary infiltrates with alveolar, interstitial, mixed and peribronchial/perivascular patterns in all patients, including one with negative standard radiographic findings. Infectious agents were excluded. Histology of the lung biopsy/autopsy specimens showed leukaemic infiltrates. Pulmonary leukaemia may be the cause of pulmonary infiltrates, even in non-hyperleucocytosic AML patients with low blast counts.

Acute Disease↗

Assessment of invasive growth pattern and lymphocytic infiltration in colorectal cancer.

A total of 122 specimens of colorectal cancer were re-assessed in relation to the reporting of invasive growth pattern (expanding vs. infiltrating) and presence or absence of peritumoral lymphocytic infiltrate as used in the Jass prognostic classification. Jass agreed with 69% of cases reported as infiltrating and 90% of reported as expanding. This parameter was distributed similarly amongst Dukes B and C cases in the original assessment (P = 0.27), whereas in the reviewed data infiltrating cases were more likely to be staged as Dukes C (P = 0.04). Jass agreed with 44% of lymphocyte present and 94% of lymphocyte absent assessments. The original lymphocyte assessments showed no significant differences in distribution between Dukes A and B cases (P = 0.12) or B and C cases (P = 0.75), whereas the reviewed data showed significant differences for A vs. B (P = 0.015) and B vs. C cases (P = 0.0025). Criteria for assessment were circulated to eight observers who revisited 20 of the cases in which there was disagreement. Consensus agreement with Jass was achieved in nine of 10 cases for invasive growth pattern and seven of 10 cases for lymphocyte infiltration (with two being evenly split). Most observers showed at least fair levels of agreement with Jass and some achieved excellent levels of agreement. This study indicates that assessment of criteria used in the Jass prognostic system for colorectal cancer is less than optimal in routine practice, but is improved through the provision of simple guidelines.

Colorectal Neoplasms↗

Characterization of cellular infiltration in choroidal melanoma.

An immunohistochemical double staining technique was used to examine the characteristics of cellular infiltration in choroidal melanoma. Seven of 16 melanomas examined demonstrated high levels of cellular infiltration, mainly with T-cells and macrophages, and little infiltration with B-cells and NK cells. The majority of T-cells were of the CD8+ type and were activated, as shown by the expression of histocompatibility antigens, HLA-DR and IL2-R. Most of the infiltrating macrophages also expressed HLA-DR antigen. We also detected malignant melanocytes expressing the HLA-DR antigen. This technique could be used to study in detail cellular infiltration in a large number of archival choroidal melanomas with known clinical history, which would enable detection of markers that correlate with the prognosis of the disease.

B-Lymphocyte Subsets↗

Dendritic cell density and activation status of tumour-infiltrating lymphocytes in metastatic human melanoma: possible implications for sentinel node metastases.

Nodal deposits of melanoma may present many years after resection of the primary tumour, implying initial suppression of tumour growth with subsequent immune escape. Using immunocytochemical techniques on frozen sections, the cellular types and activation status of infiltrating cells within a series of 19 clinically apparent nodal metastases of melanoma were studied. Infiltrating cells were assessed using a semiquantitative grading system. Macrophages (CD68+) and T-lymphocytes (CD3+) (including both CD8+ and probably also CD4+ T-cells) were the predominant cells infiltrating the tumours. B-lymphocytes (CD20+) were generally present in low numbers. CD1a+ putative dendritic cell density and expression of the early lymphocyte activation markers interleukin-2 receptor alpha (IL2Ralpha) and CD69 was low. However, greater evidence of intermediate lymphocyte activation (CD38) was identified. Expression of interleukin-2 (IL2) by tumour-infiltrating cells was not detected. The paucity of staining for IL2 and IL2Ralpha, with greater expression of CD38 by infiltrating cells, suggests that the usual pathways of lymphocyte activation via IL2 were bypassed or impaired within the lymph node metastases. Low numbers of CD1a+ putative dendritic cells may result in reduced effector cell activation. These findings provide evidence to support the hypothesis that antitumour immune responses within clinically involved lymph nodes are reduced in metastatic melanoma. This also has possible implications for micrometastases to the sentinel lymph node.

Dendritic Cells↗