Mononuclear cell infiltration in central portions of human astrocytomas

TREM-1 and TREM-2 Expression on Blood Monocytes Could Help Predict Survival in High-Grade Glioma Patients

Objective

In recent years, the role of the modern inflammatory markers TREM-1 (triggering receptors expressed on myeloid cells) and HMGB1 (high mobility group box 1 protein) in tumorigenesis has begun to be studied. Their role in gliomas is not clear. The aim of our study was to find the role of inflammation in gliomas. Patients and Methods. In 63 adult patients with gliomas and 31 healthy controls, the expressions of TREM-1 and TREM-2 on CD14⁺ blood cells (method: flow cytometry) and the levels of soluble sTREM-1, HMGB1, IL-6, and IL-10 (Elisa tests) were analyzed.

Results

Cox proportional hazard analysis showed that a TREM-1/TREM-2 ratio was associated with reduced overall survival (HR = 1.001, P = 0.023). Patients with a TREM-1/TREM-2 ratio above 125 survived significantly shorter than patients with a TREM-1/TREM-2 ratio below 125. The percentage of CD14⁺ TREM-1⁺ cells was strongly associated with a plasma IL-6/IL-10 ratio (positively) and with IL-10 (negatively). Conversely, we found a higher percentage of CD14⁺ TREM-2⁺ monocytes in better surviving patients; these cells could downregulate the exaggerated inflammation and potentiate the phagocytosis in the tumor. The serum levels of HMGB1 negatively correlated with the percentage of CD14⁺ TREM-1⁺ cells and with the TREM-1/TREM-2 ratio. The positive correlation between the serum levels of a late proinflammatory cytokine HMGB1 with the percentage of TREM2⁺ CD14⁺ monocytes can be explained as an effort for suppression of systemic inflammation by anti-inflammatory acting CD14⁺ TREM-2⁺ cells.

Conclusion

We showed that the TREM-1/TREM-2 ratio (expression on the surface of blood monocytes) could help predict prognosis in patients with gliomas, especially in high-grade gliomas, and that systemic inflammation has an impact on the patient's overall survival. This is the first study that showed that TREM expression on monocytes in peripheral blood could help predict prognosis in patients with gliomas.

Distribution of tumor-infiltrating immune cells in glioblastoma

Aim:

Evaluation of features related to infiltrating immune cell level in glioblastoma.

Methods:

Tumor-infiltrating lymphocytes (TILs) through H&E staining, and TILs (CD3, CD4, CD8 and CD20) and macrophage (CD68 and CD163) levels through immunohistochemistry were evaluated through digital analysis.

Results:

CD68 (9.1%), CD163 (2.2%), CD3 (1.6%) and CD8 (1.6%) had the highest density. Higher CD4⁺ was associated with unmethylated MGMT (p = 0.016). Higher CD8⁺ was associated with larger tumoral size (p = 0.027). Higher CD163⁺ was associated with higher age (p = 0.044) and recursive partitioning analysis = 4. Women (p < 0.05), total resection (p < 0.05), MGMT-methylation (p < 0.001), radiotherapy (p < 0.001), chemotherapy (p < 0.001) and lower CD4⁺ (p < 0.05) were associated with longer overall survival.

Conclusion:

Macrophages are more frequent than TILs. Some subsets are associated with clinical features.

Prognostic role of tumour-infiltrating inflammatory cells in brain tumours: literature review

PURPOSE OF REVIEW

Both primary and metastatic brain tumours pose a significant and unmet clinical need. Immune cells infiltrating the tumour have been shown to affect the clinical course of various extracranial tumour types, but there is little knowledge on the role of tumour-infiltrating immune cells in brain tumours. Thus, the aim of this review was to recapitulate the reports on immune infiltrates in brain tumours and their prognostic significance.

RECENT FINDINGS

Immune infiltrates composed of various lymphocyte subsets and microglia/macrophages are frequently observed in brain tumours; however, their density and prognostic role seem to differ between tumour types. Central nervous system (CNS) metastases, particularly of melanoma, lung cancer and renal cell cancer, commonly show high amounts of tumour-infiltrating lymphocytes and tumour-infiltrating lymphocytes density strongly correlate with patient's overall survival times in patients with CNS metastases. In gliomas and primary CNS lymphomas, some studies also suggest a prognostic role of immune cell infiltration; however, methodological issues such as low sample size and retrospective study designs with heterogeneous patient populations preclude definite conclusions. Meningiomas typically harbour inflammatory infiltrates, but their correlation with the clinical course is unclear because of the lack of studies correlating immune cell infiltrates with outcome parameters.

SUMMARY

The available literature suggests a relevant role of immune infiltrates in the clinical course of some brain tumour types; however, further studies are required to better understand the interaction of the immune system and CNS neoplasms and to explore therapeutic opportunities with immunotherapies such as vaccines or immune checkpoint modulators.

Genomic Analysis of Immune Cell Infiltrates Across 11 Tumor Types

BACKGROUND

Immune infiltration of the tumor microenvironment has been associated with improved survival for some patients with solid tumors. The precise makeup and prognostic relevance of immune infiltrates across a broad spectrum of tumors remain unclear.

METHODS

Using mRNA sequencing data from The Cancer Genome Atlas (TCGA) from 11 tumor types representing 3485 tumors, we evaluated lymphocyte and macrophage gene expression by tissue type and by genomic subtypes defined within and across tumor tissue of origin (Cox proportional hazards, Pearson correlation). We investigated clonal diversity of B-cell infiltrates through calculating B-cell receptor (BCR) repertoire sequence diversity. All statistical tests were two-sided.

RESULTS

High expression of T-cell and B-cell signatures predicted improved overall survival across many tumor types including breast, lung, and melanoma (breast CD8_T_Cells hazard ratio [HR] = 0.36, 95% confidence interval [CI] = 0.16 to 0.81, P = .01; lung adenocarcinoma B_Cell_60gene HR = 0.71, 95% CI = 0.58 to 0.87, P = 7.80E-04; melanoma LCK HR = 0.86, 95% CI = 0.79 to 0.94, P = 6.75E-04). Macrophage signatures predicted worse survival in GBM, as did B-cell signatures in renal tumors (Glioblastoma Multiforme [GBM]: macrophages HR = 1.62, 95% CI = 1.17 to 2.26, P = .004; renal: B_Cell_60gene HR = 1.17, 95% CI = 1.04 to 1.32, P = .009). BCR diversity was associated with survival beyond gene segment expression in melanoma (HR = 2.67, 95% CI = 1.32 to 5.40, P = .02) and renal cell carcinoma (HR = 0.36, 95% CI = 0.15 to 0.87, P = .006).

CONCLUSIONS

These data support existing studies suggesting that in diverse tissue types, heterogeneous immune infiltrates are present and typically portend an improved prognosis. In some tumor types, BCR diversity was also associated with survival. Quantitative genomic signatures of immune cells warrant further testing as prognostic markers and potential biomarkers of response to cancer immunotherapy.

Diversity and divergence of the glioma-infiltrating T-cell receptor repertoire

Although immune signaling has emerged as a defining feature of the glioma microenvironment, how the underlying structure of the glioma-infiltrating T-cell population differs from that of the blood from which it originates has been difficult to measure directly in patients. High-throughput sequencing of T-cell receptor (TCR) repertoires (TCRseq) provides a population-wide statistical description of how T cells respond to disease. We have defined immunophenotypes of whole repertoires based on TCRseq of the α- and β-chains from glioma tissue, nonneoplastic brain tissue, and peripheral blood from patients. Using information theory, we partitioned the diversity of these TCR repertoires into that from the distribution of VJ cassette combinations and diversity due to VJ-independent factors, such as selection due to antigen binding. Tumor-infiltrating lymphocytes (TILs) possessed higher VJ-independent diversity than nonneoplastic tissue, stratifying patients according to tumor grade. We found that the VJ-independent components of tumor-associated repertoires diverge more from their corresponding peripheral repertoires than T-cell populations in nonneoplastic brain tissue, particularly for low-grade gliomas. Finally, we identified a "signature" set of TCRs whose use in peripheral blood is associated with patients exhibiting low TIL divergence and is depleted in patients with highly divergent TIL repertoires. This signature is detectable in peripheral blood, and therefore accessible noninvasively. We anticipate that these immunophenotypes will be foundational to monitoring and predicting response to antiglioma vaccines and immunotherapy.

Reciprocal Supportive Interplay between Glioblastoma and Tumor-Associated Macrophages

Glioblastoma multiforme (GBM) is the most lethal and aggressive type of primary brain malignancy. Failures of the traditional therapies in treating GBMs raise the urgent requirement to develop new approaches with more responsive targets. The phenomenon of the high infiltration of tumor-associated macrophages (TAMs) into GBMs has been observed for a long time. Regardless of the limited knowledge about TAMs, the high percentage of supportive TAM in GBM tumor mass makes it possible to be a good target for GBM treatment. In this review, we discussed the unique features of TAMs in GBMs, including their origin, the tumor-supportive properties, the secreted cytokines, and the relevant mechanisms. In addition, we tried to interpret the current understandings about the interplay between GBM cancer cells and TAMs. Finally, the translational studies of targeting TAMs were also described.

Immune cell infiltrate differences in pilocytic astrocytoma and glioblastoma: evidence of distinct immunological microenvironments that reflect tumor biology

OBJECT

The tumor microenvironment in astrocytomas is composed of a variety of cell types, including infiltrative inflammatory cells that are dynamic in nature, potentially reflecting tumor biology. In this paper the authors demonstrate that characterization of the intratumoral inflammatory infiltrate can distinguish high-grade glioblastoma from low-grade pilocytic astrocytoma.

METHODS

Tumor specimens from ninety-one patients with either glioblastoma or pilocytic astrocytoma were analyzed at the University of California, San Francisco. A systematic neuropathology analysis was performed. All tissue was collected at the time of the initial surgery prior to adjuvant treatment. Immune cell infiltrate not associated with necrosis or hemorrhage was analyzed on serial 4-μm sections. Analysis was performed for 10 consecutive hpfs and in 3 separate regions (total 30 × 0.237 mm(2)). Using immunohistochemistry for markers of infiltrating cytotoxic T cells (CD8), natural killer cells (CD56), and macrophages (CD68), the inflammatory infiltrates in these tumors were graded quantitatively and classified based on microanatomical location (perivascular vs intratumoral). Control markers included CD3, CD20, and human leukocyte antigen.

RESULTS

Glioblastomas exhibited significantly higher perivascular (CD8) T-cell infiltration than pilocytic astrocytomas (62% vs 29%, p = 0.0005). Perivascular (49%) and intratumoral (89%; p = 0.004) CD56-positive cells were more commonly associated with glioblastoma. The CD68-positive cells also were more prevalent in the perivascular and intratumoral space in glioblastoma. In the intratumoral space, all glioblastomas exhibited CD68-positive cells compared with 86% of pilocytic astrocytomas (p = 0.0014). Perivascularly, CD68-positive infiltrate was also more prevalent in glioblastoma when compared with pilocytic astrocytoma (97% vs 86%, respectively; p = 0.0003). The CD3-positive, CD20-positive, and human leukocyte antigen-positive infiltrates did not differ between glioblastoma and pilocytic astrocytoma.

CONCLUSIONS

This analysis suggests a significantly distinct immune profile in the microenvironment of high-grade glioblastoma versus low-grade pilocytic astrocytoma. This difference in tumor microenvironment may reflect an important difference in the tumor biology of glioblastoma.

CD8+ T-cell infiltrate in newly diagnosed glioblastoma is associated with long-term survival

A growing body of evidence supports the significant interplay between the immune system and glioma pathogenesis. Here we investigate whether the extent of local glioma-associated CD8+ T-cell infiltrate at initial presentation correlates with long-term survival in patients with glioblastoma multiforme (GBM). The study was conducted by the University of California San Francisco Brain Tumor Research Center as part of the San Francisco Bay Area Adult Glioma Study, which included over 519 patients with GBM. A central neuropathology review was performed and populations of infiltrating CD8+ T-cells were quantified histologically. Of 108 patients studied, 43 patients had poor survival (<95days) and 65 patients had extended long-term survival of >403days. Tumors from long-term survivors were more likely than short-term survivors to have intermediate or extensive T-cell infiltrates compared to focal or rare infiltrates, and this association appears to be most significant in Caucasian women (p < 0.006). Thus, CD8+ T-cell infiltrate is associated with prolonged survival. Our data provide the impetus for more sophisticated studies to further elucidate prospectively the specific T-cell subtypes associated with long-term survival.

CC-chemokine ligand 18/pulmonary activation-regulated chemokine expression in the CNS with special reference to traumatic brain injuries and neoplastic disorders

Pulmonary activation-regulated chemokine (PARC) now designated CC-chemokine ligand 18 (CCL18) has been shown to play a significant role in the pathogenesis of various tissue injuries and diseases in a proinflammatory or immune suppressive way to limit or support the inflammation or disease. While much is known about the roles of CCL18/PARC in non-neural tissues, its expression in the CNS has remained largely unexplored and controversial. Using reverse transcription polymerase chain reaction (RT-PCR) and double immunohistochemical staining, we analyzed the expression of CCL18/PARC in the human brain with special reference to traumatic brain injuries and tumors. The RT-PCR analysis revealed the expression of CCL18/PARC mRNA both in the traumatic brain and glioma tissues examined. Immunoexpression of CCL18/PARC protein was consistently detected in all cases of traumatic brain injuries examined by immunohistochemical staining. Double immunofluorescence labeling has extended the study that CCL18/PARC positive cells were macrophages/microglia, astrocytes or neurons. The CCL18/PARC expression was localized in macrophage-like cells in two of eight glioblastoma tissues whose cancer cells were CCL18/PARC negative. Unexpectedly, CCL18/PARC mRNA weakly and constitutively expressed by glioblastoma cell line was upregulated after endotoxin stimulation. The present results indicated a significant production of CCL18/PARC in different CNS traumatic and neoplasm tissues by specific cellular elements expressing the chemokine. An anti-inflammatory mechanism jointly exerted by these cells via CCL18/PARC may be involved in the CNS immunity after traumatic injury and tumorigenesis.

Gemistocytic astrocytomas: histomorphology, proliferative potential and genetic alterations – a study of 32 cases

Gemistocytic astrocytomas (GAs) are a distinct variant of astrocytomas, generally classified as WHO grade II, and are associated with an aggressive biological behavior. This study was undertaken to determine the histomorphological spectrum, and correlate these with their proliferative potential and genetic alterations, in order to establish a biological basis for their unfavorable prognosis.A total of 32 GAs diagnosed during an 11-year period (1993-2003) were included in the study. Immunoreactivity for CD3 (T-cells), CD20 (B-cells) and CD68 (macrophages) were evaluated to characterize the perivascular inflammatory infiltrates, while p53, epidermal growth factor receptor (EGFR), cyclin D1 and p27-immunolabeling were studied to analyze the tumor biology.Overall, the mean gemistocytic index in the study was 39.6% (range, 12.2-80.8%), with multinucleation in gemistocytes and mitosis being present in 56.2% and 15.6% respectively. Perivascular mononuclear cell cuffing was seen in 56.2% cases, which was immunopositive for CD3 and CD68 in 14 cases each, with 13 cases being immunopositive for both. Similar type of inflammatory infiltrates was also present within the tumor parenchyma. Proliferation index depicted by MIB-1 LI was low (mean: 3.7%; range: 0.5-10.5%), with 70% cases having LI of <5%. MIB-1 labeling was restricted to the small astrocytic cells, similar to p27 and cyclin D1 immunoreactivity, both of which were present in 71.5% cases. In contrast, p53 protein expression was present in 75% cases, and was strongly positive in both gemistocytes and small cells, denoting neoplastic population. However, EGFR protein expression was consistently negative in all cases. Gemistocytes lack proliferative activity possibly indicating terminal differentiation, while small cells are the proliferating cells and their overall percentage may reflect the biological aggressiveness of these tumors and help to identify GAs of higher grade undergoing malignant progression. Therefore it appears that GAs should not be uniformly graded as grade II but should be subdivided into grades II and III neoplasms based on histological features and MIB-1 LI. The poor prognosis in GAs could be attributed both to the high frequency of p53 mutations and low p27 LI.

Current and Future Gene Therapy for Malignant Gliomas

Malignant gliomas are the most common neoplasm in the central nervous system. When treated with conventional treatments including surgery, irradiation, and chemotherapy, the average life expectancy of the most malignant type, glioblastoma multiforme is usually less than 1 year. Therefore, gene therapy is expected to be an effective and possibly curative treatment. Many gene therapeutic approaches have demonstrated efficacy in experimental animal models. However, the current clinical trials are disappointing. This review focuses on current therapeutic genes/vectors/delivery systems/targeting strategies in order to introduce updated trends and hopefully indicate prospective gene therapy for malignant gliomas.

Malignant glioma cells use MHC class II transactivator (CIITA) promoters III and IV to direct IFN-gamma-inducible CIITA expression and can function as nonprofessional antigen presenting cells in endocytic processing and CD4(+) T-cell activation

Malignant gliomas (MGs), lethal human central nervous system (CNS) neoplasms, contain tumor infiltrating lymphocytes (TIL). Although MHC class II molecules are frequently detected on MG cells, suggesting that they may be capable of antigen (Ag) presentation to CD4(+) T cells, deficiencies in CD4(+) T-cell activation are associated with these nonimmunogenic tumors. We evaluated regulation of the MHC class II transactivator (CIITA), the key intermediate that controls class II expression, in MG cells and tested whether MG cells could process native Ag. After interferon-gamma (IFN-gamma) stimulation, MG cells upregulated CIITA and class II molecules. IFN-gamma-inducible CIITA expression in MG cells, as well as primary human astrocytes, was directed by two CIITA promoters, pIV, the promoter for IFN-gamma-inducible CIITA expression in nonprofessional antigen-presenting cells (APC), and pIII, the promoter that directs constitutive CIITA expression in B cells. Both pIII and pIV directed CIITA transcription in vivo in MGs and ex vivo in IFN-gamma-activated primary MG cultures. We also demonstrate for the first time that MG cells can process native Ag for presentation to CD4(+) MHC class II-restricted Th1 cells, indicating that MG cells can serve as nonprofessional APC. CIITA may be a key target to modulate MHC class II expression, which could augment immunogenicity, Ag presentation, and CD4(+) T-cell activation in MG therapy.

Ham56-immunoreactive macrophages in untreated infiltrating gliomas

CONTEXT

Classic diagnostic neuropathologic teachings have cautioned against making the diagnosis of neoplasia in the presence of a macrophage population. The knowledge of macrophage distribution should prove useful when confronted with an infiltrating glioma containing macrophages.

OBJECTIVE

To identify macrophages in untreated, infiltrating gliomas using the monoclonal antibody HAM56, and to confirm their presence in an untreated glioblastoma multiforme (GBM) with the serial analysis of gene expression (SAGE) method.

METHODS

We evaluated the presence of macrophages in 16 cases of untreated, supratentorial infiltrating gliomas with the macrophage monoclonal antibody HAM56. We performed SAGE for one case of GBM and for normal brain tissue.

RESULTS

In World Health Organization (WHO) grade II well-differentiated astrocytoma and oligodendroglioma, HAM56 reactivity was noted only in endothelial cells, and unequivocal macrophages were not identified. In WHO grade III anaplastic astrocytoma and anaplastic oligodendroglioma, rare HAM56-positive macrophages were noted in solid areas of tumor. In WHO grade IV GBM, HAM56-positive macrophages were identified in areas of solid tumor (mean labeling index, 8.6%). In all cases of GBM, nonquantitated HAM56-positive macrophages were identified in foci of pseudopalisading cells abutting necrosis and in foci of microvascular proliferations. In none of the cases were granulomas or microglial nodules found, and there was no prior history of surgical intervention, radiation therapy, chemotherapy, or head trauma in these cases. By SAGE, the macrophage-related proteins osteopontin and macrophage-capping protein were overexpressed 12-fold and eightfold, respectively, in one untreated GBM compared with normal brain tissue. In this case, numerous HAM56-positive macrophages (labeling index, 24.5%) were present in the solid portion of tumor, and abundant nonquantified macrophages were identified in foci of pseudopalisading cells abutting necrosis and in foci of microvascular proliferations.

CONCLUSIONS

This study confirms the utility of the monoclonal antibody HAM56 in identifying macrophages within untreated infiltrating gliomas. The overexpression of macrophage-related proteins in one case of GBM as detected by SAGE signifies that macrophages may be present in untreated GBMs.

Expression of the SART3 tumor-rejection antigen in brain tumors and induction of cytotoxic T lymphocytes by its peptides

The authors recently reported on the SART3 tumor-rejection antigen, which possesses epitopes that can induce cytotoxic T lymphocytes (CTLs) in patients with epithelial cancer. To explore a new modality for treatment of patients with brain tumors, this study investigated the expression of the SART3 antigen in patients with brain tumors and the ability of SART3 peptides to induce CTLs from peripheral blood mononuclear cells (PBMCs) of these patients. The SART3 antigen was detected in the cytoplasmic fraction of all 18 glioma cell lines examined and in the majority (31 of 34; 91%) of brain tumor tissues irrespective of their histologies. It was also expressed in the nuclear fraction of all 18 glioma cell lines and in the majority (26 of 34; 76%) of brain tumor tissues. In contrast, the SART3 was not expressed in nontumorous brain tissues. Cytotoxic T lymphocytes were induced in patients with glioma by stimulation with two epitope peptides of SART3. These CTLs could eliminate glioma cells in a HLA-A24-restricted manner. Therefore, the SART3 peptides may be appropriate molecules for use in peptide-based specific immunotherapy of HLA-A24+ patients with brain tumors.

Tenascin expression patterns and cells of monocyte lineage: relationship in human gliomas

Stromal extracellular matrix (ECM) components are thought to play an important role in regulating invasion of human gliomas. Macrophages and microglial cells may heavily influence the integrity of the extracellular compartment of gliomas, and the affected ECM may play a key role in regulating migratory activity of both tumor cells and macrophages/microglia. The aim of this investigation was to study immunohistochemically the expression patterns of four ECM components: fibronectin, laminin, collagen IV, and tenascin (TN) in human gliomas, with special attention to TN. Our main goal was to study the possible correlation between TN expression and macrophagic/microglial infiltration in gliomas. Altogether, 90 gliomas were studied. Tumors included 46 glioblastomas, 19 anaplastic gliomas, 22 low grade gliomas, and 3 pilocytic astrocytomas. Vascular TN prevailed in perinecrotic areas of glioblastomas, whereas interstitial TN was more often expressed distant from necrosis and in the ECM of anaplastic and low grade gliomas. Double staining with CD68 and anti-TN antibodies showed that macrophagic/microglial density was significantly higher in TN-positive areas of most of the glioblastomas and anaplastic gliomas, whereas microglial percentage from total number of CD68-positive cells was in most of the cases significantly higher in TN-negative areas. In addition, we saw a morphologically spatial correlation between higher densities of macrophagic/microglial infiltration and TN expression in perinecrotic areas in glioblastomas. Attachment of macrophages to TN-positive basement membrane zones of newly formed stromal blood vessels was evident. On the basis of our results, we conclude that TN may play a crucial role in regulating trafficking of cells of monocyte lineage in human gliomas.

Fluorescence automatic cell sorter and immunohistochemical investigation of CD68-positive cells in meningioma

Infiltration of brain neoplasms by mononuclear cells including monocytes/macrophages has attracted little attention since they have marked morphological heterogeneity. Twenty-seven meningiomas were studied by anti-CD68 antibody-gated flow cytometry and by immunohistochemical analysis using the anti-CD68 antibodies. Flow cytometric analysis divided cells contained within tumor tissues into CD68-positive and -negative cells. In addition, eight gliomas, eight metastatic brain tumor, and 12 pituitary adenomas were investigated in the same way to compare meningiomas. The mean contents of CD68-positive cells were 24.0 +/- 3.7% in meningiomas, 4.4 +/- 1.4% in gliomas, 9.5 +/- 3.9% in metastatic brain tumors, and 4.5 +/- 1.8% in pituitary adenomas. Immunohistochemically, CD68-positive cells showed significant heterogeneity and were detected as round, rod-shaped, ameboid and ramified cells in meningiomas. Although the infiltrated mononuclear cells in gliomas have been investigated to some degree and showed that they express cytokines and/or growth factors, these infiltrated cells in meningioma have barely been studied. The CD68-positive cells detected in this study are likely to be monocytes, macrophages and microglias, and are presumed to be in various functional stages and to play important roles in growth regulation in meningioma.

Astrocytoma infiltrating lymphocytes include major T cell clonal expansions confined to the CD8 subset

Anaplastic astrocytoma and glioblastoma are frequent and malignant brain tumors that are infiltrated by T lymphocytes. Whether these cells result from non-specific inflammation following blood-brain barrier disruption or an antigen-driven specific immune response is unknown. In this study, an in-depth characterization of TCR diversity in tumor and blood RNA biopsies was performed in a series of 16 patients with malignant astrocytoma. Whilst there was no obvious restriction of the AV and BV gene segment usage, complementarity-determining region 3 size analysis and sequencing of amplified TCR transcripts revealed multiple T cell oligoclonal expansions in all astrocytomas analyzed. Unique T cell clones were present in different adjacent areas of a given tumor, but never detected in the blood. Quantification of the number of TCR clonal transcripts per microg of tumor RNA indicated that certain T cell clonal expansions may represent at least 300 cells/10(6) tumor cells. Furthermore, we demonstrated that the in vivo expanded clones were almost exclusively confined to the CD8(+) subset. Overall, these data suggest that spontaneous antigen-driven immune responses may be elicited against human astrocytoma despite the immunosuppressive microenvironment generated by the brain and the tumor itself. However, the ultimate failure of the immune system to control tumor growth could be the consequence of a deficient CD4 T(h) component of the response. This observation could have important consequences for the development of immunotherapies for astrocytoma patients.

Human retinoblastoma: a morphological study of apoptotic, leukocytic, and vascular elements

Retinoblastoma (Rb), derived from retinal neuroepithelial progenitor cells, is the most common intraocular malignancy of childhood. This study examined 10 human Rb biopsy specimens with light and electron microscopy for histopathological features not previously described in detail, including cell death, leukocytic infiltration, and the tumor vasculature. Rb is a solid well-vascularized tumor with regions of viable tumor cells surrounding vessels, interspersed with zones of necrosis; apoptotic cells were seen in all specimens. Mononuclear phagocyte series (MPS) cells and lymphocytes often colocalized, adjacent to tumor vessels, and MPS cells frequently invested the perivascular space. Lymphocytes were rarely seen within areas of viable tumor. Tumor vessels at early stages of formation resembled normal developing retinal vessels. While junctions were often seen between endothelial calls, disruption of these junctions and endothelial fenestrae was sometimes evident. Müller cells and astrocytes extended processes around tumor cells and blood vessels, and contributed to the formation of the vascular glia limitans, which in some mature vessels was disrupted and discontinuous. Overall, this study provides further morphological details of cell death within Rb, particularly apoptotic involution, and describes the presence of a vascular-associated leukocytic infiltration in Rb. Evidence of compromise of the normal blood-retinal barrier (BRB) within the Rb tumor vessels is presented.

Immune infiltrates and cytokines in gliomas

Frozen sections of 21 gliomas were analysed to characterize inflammatory infiltrating cells, HLA-DR antigen expression and cytokine secretion. Mononuclear cells infiltrating the tumours were mostly macrophages, which were detected in 100% of cases, and expressed HLA-DR antigens. Lymphocytes were less frequently seen and expressed the CD8 phenotype. Interleukin-1 beta (IL-1 beta) and Interleukin-6 (IL-6), two cytokines mainly produced by activated cells of the macrophage lineage, were demonstrated especially in neoplastic astrocytes. IL-1 beta immunoreactivity was detected in all tumours, and was prevalent in more anaplastic gliomas; IL-6 was found in anaplastic gliomas and in glioblastomas. IL-1 receptors were expressed by both infiltrating macrophages and neoplastic astrocytes in the gliomas analysed. These findings suggest that cytokine production in gliomas seems not related to immune reactions against the tumour and their synthesis by anaplastic astrocytes could follow an unregulated activation of many metabolic processes after neoplastic transformation.

The role of chemotherapy in recurrent malignant gliomas: an overview

First-line treatment of malignant gliomas invariably includes surgery when feasible, and often adjuvant radiotherapy with or without chemotherapy; at progression or recurrence, the only remaining possibility is chemotherapy. While the role of first-line treatment has been established by many randomized studies, second-line treatment is not as well defined. To analyze the difficulties encountered with cytotoxic drugs in relation to both the blood-brain barrier and drug resistance, we examined the results obtained by single-agent chemotherapy, drug combinations, and biological response modifiers. Our findings confirmed that the nitrosoureas are the most active substances at the time of recurrence; these agents give an approximately 30% global response rate, with about 20 weeks' survival. Although no comparative randomized studies regarding single- versus multiple-agent chemotherapy are available, the latter approach, including nitrosourea, can obtain an up to 40% rate of response, with survival ranging from 30 to 50 weeks. The role of interferons has been very controversial; individually, alpha- and beta-interferons seem to give a 20% response rate, with 20 weeks' survival. To date, they have never been used in combination with cytotoxic drugs, but they may prove synergistic without increasing toxicity. Studies addressing the quality of life of these patients are not available, and it is clear that we need more basic research in this field.

Extracellular matrix-degrading proteinases in the nervous system

The proteolytic activities of matrix metalloproteinases and plasminogen activators as well as their inhibitors are important in maintaining the integrity of the extracellular matrix (ECM). Cell-ECM interactions influence cell proliferation, differentiation, adhesion and migration. In the nervous system, proteolysis of the ECM is involved in neuronal cell migration in the developing cerebellum and in neurite outgrowth. Likewise, in pathological conditions such as brain tumour growth and invasion, leukocyte infiltration into brain tumours, leukocyte trafficking in the central nervous system in inflammatory diseases such as multiple sclerosis and viral encephalitis, and in nerve demyelination, matrix-degrading proteinases and their inhibitors have been implicated. An understanding of cell-ECM interactions and ECM degradation in diseases of the nervous system would provide new insight for drug design and other forms of therapy.

Antitumor effects of human recombinant macrophage colony-stimulating factor against rat brain tumors

The tumoricidal effects of M-CSF were examined using two subcutaneously-transplanted rat brain tumor cell lines, 9L and T9 gliomas. In rats treated with high-dose M-CSF (16 million U/kg administered for 4 days a week for 3 weeks), 9L glioma growth was inhibited by 81.9% following subcutaneous (s.c.) injection and by 70.5% after intraperitoneal (i.p.) injection and T9 glioma growth was inhibited by 69.2% after i.p. injection. After short-term treatment with high-dose M-CSF (32 million U/kg administered s.c. for 6 consecutive days, 9L glioma growth was inhibited by 82.1%. All these inhibitory effects differed significantly compared with the respective untreated control groups. However, treatment with low-dose M-CSF (1.6 million U/kg administered s.c. for 4 days a week for 3 weeks) showed no significant effects against 9L and T9 glioma growth compared with the untreated controls. No significant effects of M-CSF against cell proliferation, measured as PCNA expression, were observed in any group. Significant hematopoietic effects on the leukocyte counts were observed only in the groups treated with high dose M-CSF. These results suggest that M-CSF at a high dose which produces hematopoietic effects on peripheral leukocytes inhibits the growth of gliomas. This inhibitory effect may have been due to a tumoricidal mechanism of M-CSF that depended on the production or release of some hematopoietic soluble factors, but was independent of PCNA expression by the tumors.

An immunohistochemical study of mononuclear cells in meningiomas

A consecutive series of 34 meningiomas were re-examined as to subtype and presence of nuclear atypia, mitotic figures, areas of high cellularity and necrosis. Meningioma cells were epithelial membrane antigen (EMA) positive in 31 out of the 34 tumours. The presence of mononuclear cells and macrophages was assessed by immunohistochemistry using the monoclonal antibodies L26 (CD20, B cell marker), DF-T1 (CD43, T cell marker), KP1 (CD68, macrophage marker) and MAC387 (monocytes). L26 positive B cells were observed infrequently. CD43 positive mononuclear cells were infiltrating the parenchyma as individual cells and as groups of cells in 29 (87% of the tumours). CD68 positive macrophages were seen in 19 (59% of the tumours), as scattered single cells or groups of cells. There was a statistically significant association between the number of CD68 positive cells (necrotic areas excluded) and microscopic features of aggressiveness, i.e. high cellularity as well as the combination of nuclear atypia and frequent mitotic figures. MAC387 stained only a few cells; the immunopositive cells were present mainly within and around vessels. Meningioma cells displayed a diffuse immunopositivity for L26 (CD20) in 29 out of 34 meningiomas, but did not stain with macrophage markers. Mast cells were found in 9 out of 32 tumours; when present they were significantly more prevalent in the syncytial subtype. Thus, mononuclear cell infiltrates in meningiomas are mainly composed of T cells and macrophages, indicating an immune system surveillance and response to the tumour cells. The functional and prognostic significance of the presence of CD68 positive cells, macrophages, deserve further study in the search for more reliable histological criteria to predict recurrence and biological aggressiveness in meningiomas.

Cytokines and immunoregulatory molecules in malignant glial neoplasms

Cytokines are important regulatory proteins controlling growth and differentiation of normal and malignant glial cells. Astrocytes and microglial cells produce and respond to many of the same cytokines employed by cells of the immune system. The authors have analyzed 15 histologically confirmed malignant glial neoplasms for the presence of infiltrating lymphocytes, macrophages, cytokines, and other immunoregulatory molecules using a panel of specific monoclonal and polyclonal antibodies on frozen-tissue sections. All neoplasms showed focal T-cell infiltration with CD8 cells predominating. Infiltration of activated macrophages (positive for CD11c, class II, and interleukin-2 receptor) was marked in all tumors. Within the neoplasm, tumor necrosis factor-alpha (TNF-alpha)- and interleukin (IL)-6-positive macrophages were prominent in five cases, while the tumor cells themselves were only weakly positive. In the other 10 cases, the numerous infiltrating macrophages were only rarely immunoreactive for TNF-alpha or IL-6. Transforming growth factor-beta (TGF-beta) immunoreactivity was most prominent in those tumors with little TNF-alpha-positive macrophage infiltration, although intratumoral variability was present. This study suggests that, in malignant gliomas, the cytokines TNF-alpha and IL-6, although weakly present in neoplastic cells, are most prominent in infiltrating macrophages and in those regions of the tumors that show little immunoreactivity for TGF-beta. The important interactions among neoplastic, reactive glial, and inflammatory cells, which regulate tumor growth, are likely to be in part mediated through these molecules.

Sensitivity of human glioma and brain cells to natural killer cell lysis. Effects of serum concentration, epidermal growth factor, and time in culture

Using an in vitro monolayer natural killer (NK) cytolysis assay, the authors examined the effects of serum concentration and epidermal growth factor (EGF) on sensitivity to NK cytolysis. It was found that target cells cultured in high concentrations of serum (10% fetal bovine serum (FBS)) had higher cytotoxicity levels than those in low serum concentrations (0% to 0.5% FBS). Exposure of target cells to EGF had no effect on their sensitivity to NK cytolysis. Both glioma cell lines showed decreased NK cell sensitivity with longer times in culture. The results of cytofluorometric studies on these cell lines indicate that the differences in NK cell sensitivity may reflect the growth fraction of the target population and that a population with a higher proportion of cycling cells is more susceptible to lysis by NK cells. Whether it is possible to separate the proliferative rate of these cells from their NK cell sensitivity is unknown, but worthy of consideration.

Inflammatory cell infiltrates vary in experimental primary and metastatic brain tumors

We have studied the cellular immune response that accompanies primary and metastatic brain cancers induced experimentally in rats by inoculation of RG-2 glioma and Walker 256 (W256) carcinoma cells, respectively. The inflammatory cell infiltrates were characterized with lectin histochemistry to visualize microglial cells and macrophages and with immunohistochemistry, using a panel of monoclonal antibodies, to detect major histocompatibility complex (MHC), lymphocytic, and macrophage antigens. The metastatic tumor was composed of a loose stroma with multiple, often large, necrotic areas, whereas the RG-2 glioma was composed of a dense collection of tumor cells showing only rare necrotic foci. Both tumor types were heavily infiltrated with microglia and/or macrophages, and these were positive for MHC Class II (Ia) antigens. Expression of MHC Class I antigens was absent from RG-2 glioma cells, but it was present in W256 metastatic carcinoma cells. The metastatic tumor was also characterized by a much heavier infiltrate of lymphocytes, as shown by the presence of cells positive for CD4, CD8, and leukocyte common antigens. These lymphocytic markers were absent from reactive microglia in the W256 carcinoma, whereas they were present in the RG-2 glioma. Polymorphonuclear leukocytes were seen only in the metastatic tumor. Our study delineates differences between the inflammatory cell infiltrates found in metastatic brain tumors and those found in primary brain tumors. The differences in cell composition and immunophenotype may indicate a more effective antitumor response in the metastatic tumor that could account for the observed tissue destruction.

Immunophenotypic analysis of infiltrating leukocytes and microglia in an experimental rat glioma

The appearance and cellular distribution of major histocompatibility complex (MHC), as well as lymphocytic and macrophage antigens has been studied in a fully developed experimental rat forebrain glioma. Activated microglial cells and microglia-derived macrophages expressing CR3 complement receptor molecules and MHC class II (Ia) antigen were found throughout the tumor, and with increased density along the tumor's periphery. MHC class I antigen expression was entirely absent from tumor cells, and found only occasionally on microglia. The expression of leukocyte common antigen, and CD4 and CD8 antigens was conspicuous throughout the tumor, and associated with lymphocytes, perivascular cells, and microglia. Cells expressing the ED2 macrophage epitope were almost exclusively of the perivascular type and revealed a distribution dissimilar to that of cells positive for Ia antigen. The ED2 epitope was found sporadically on ramified microglial cells. The results show that despite heavy infiltration with blood mononuclear and CNS microglial cells, the tumor showed no evidence of destruction caused by inflammatory cells. Possible mechanisms of tumor immunosuppressive activity preventing the full immunological activation of microglia and blood mononuclear cells are discussed.

Response of microglial cells to experimental rat glioma

The response of indigenous CNS microglia to an experimentally induced glioma has been studied in rat brain using lectin histochemistry with the Griffonia simplicifolia B4-isolectin. The study was undertaken 2 weeks after tumor cell injection when tumor size was near maximal. Reactive microglial cells formed a dense band that surrounded most of the well-circumscribed tumor mass, and extended along the corpus callosum into the contralateral cerebral hemisphere. From the periphery inward, reactive microglia extended into the tumor tissue, where large numbers of them were found to be present as microglia-derived macrophages. The lectin stain, which also labels endothelial cells, revealed a highly vascularized tumor with ongoing neovascularization apparent as vascular sprouts. Moderate numbers of lectin-stained blood monocytes were localized primarily inside the vessel lumina. Our results show that microglial cells react to brain tumors; however, it remains to be determined whether the microglial response represents an active antitumor defense mechanism that could be manipulated during immunotherapeutic approaches.

Immunocytochemical study of macrophages and microglial cells and extracellular matrix components in human CNS disease. 1. Gliomas

We have used an immunocytochemical approach to investigate the inter-relationships between astrocytes, macrophages and microglia and the extracellular matrix components fibronectin and laminin, in 27 gliomas. Using recently available markers to macrophages and microglia (monoclonals Mac387, KP1 and the lectin RCA-1) and antisera to GFAP, fibronectin and laminin, we have described the reactions of these cells and the extracellular matrix. We found RCA-1 to be the superior marker for detecting most macrophages and microglia. There were more macrophages and microglia in high-grade gliomas than in low-grade. RCA-1 also reacted with endothelial cells in normal and reactive brain but showed markedly less affinity for endothelium in an close to gliomas. A possible role for the extracellular matrix in the astrocyte, macrophage and microglial reactions is discussed in the broader context of their role in the immune response.

Monocyte subpopulations in human gliomas: expression of Fc and complement receptors and correlation with tumor proliferation

Cryostat sections of 12 gliomas and of 3 peritumoral brain tissue samples were investigated for mononuclear cell infiltration by immunohistochemistry, concentrating on cells expressing monocyte/macrophage markers. Only low numbers of T cells were detected in the tumors, whereas in average 20%-30% of all cells present in the samples were recognized by various macrophage markers. These cells carried surface epitopes with known function, like Fc-gamma (Fcg) and complement receptors. Microglial cells, in comparison to typical debris laden macrophages, were only recognized by a restricted panel of macrophages markers (anti-Fcg receptors 1, 2, 3, complement receptor CR3, HLA DR, common leucocyte antigen CD45 and the monocyte marker RM3/1). In peritumoral tissue mainly dendritic, microglia-like cells were present, which revealed decreased expression of antigens CD4, RM3/1 and Fcg receptors in comparison to those in gliomas. A significant positive correlation was found between the number of RM3/1 or CR3 (CD11b)-positive cells and the proliferation rate of the tumors as documented by the number of bromodeoxyuridine-positive or Ki-67+ cells.

Immunohistochemical study of natural killer cells in tumor-infiltrating lymphocytes of primary intracranial germinomas

A monoclonal antibody against the surface marker IOT-10 of natural killer (NK) cells was used to investigate the presence and distribution of these cells in a series of nine primary intracranial germinomas. In all of these tumors, IOT-10-positive NK cells were found in small numbers, mainly distributed among the tumor cells. The data obtained in the present study suggest that the presence of NK cells in primary intracranial germinomas can be influenced by factors other than the mere quantity of tumor-infiltrating lymphocytes.

Immunohistochemical study of IOT-10 natural killer cells in brain metastases

The presence of NK-cells in a series of 40 metastatic brain tumours has been studied by means of the monoclonal antibody IOT-10. There appeared IOT-10 NK-cells in all tumours studied, but in most cases these cells represented less than 10% of the tumour infiltrating lymphocytes (TIL). In the present series, the obtained data suggest that the number of NK-cells in brain metastases can be influenced by other factors than the mere quantity of TIL.

Immunobiology of brain tumors

In summary, many actual interactions between tumors in the CNS and the immune system have been demonstrated. The normal brain does not possess a lymphatic system and is partially hidden from the systemic immune system by the BBB, furthermore brain cells do not express MHC antigens which are necessary for the initiation of an immune response. In pathological conditions however, immunocompetent cells may find their way through transformed endothelial cells. Microglia and astrocytes may function as antigen presenting cells. Glioma cells when stimulated by cytokines such as IFN gamma can be induced to express MHC class I and class II antigens, thus making them more susceptible to an immune attack. In addition glioma cells are capable of secreting several cytokines including IL 1, IL 3 and IL 6 also involved in the generation of an immune response. Indeed, a functional analysis of lymphocytes infiltrating gliomas has revealed the accumulation at the tumor site of cytotoxic T lymphocytes as well as NK cells. However host-immune responses against gliomas seem to be weak in comparison to other cancers. Glioma cells are known to secrete TGF beta 2 and PGE 2 which may in part be responsible for this lack of immune response, thus shielding themselves from immune attack. In order to be recognized by the immune system the tumor cells must express TAA in addition to MHC antigens, and such TAA have been identified by MAbs. These MAbs can be used for "targeted" therapy when coupled to toxic agents or radionuclides. Preclinical studies have shown that, after intravenous or intracarotid injection, there is specific accumulation of the MAb in the tumor but in insufficient amounts for therapeutic use. The relatively small amount of MAb binding to the tumor in vivo can be due to several factors: not all the cells in a single tumor express a given tumor-associated antigens, the MAb may have a low affinity for the antigen, the BBB may hinder the passage of the MAb. Attempts have been made to overcome these drawbacks by opening the BBB for example. In addition MAbs can readily be used for the treatment of carcinomatous meningitis. There has been little success in the development of immunotherapy with IFN beta 1 and even less with adoptive immunotherapy using LAK cells plus IL 2. TIL as well as LAK cells can be expanded in vitro with IL2 and it is feasible to reinject these cells into the tumor site.(ABSTRACT TRUNCATED AT 400 WORDS)

Lectin histochemistry of human gliomas

Formalin-fixed and paraffin-embedded specimens of 24 human gliomas were examined histochemically with five lectins; concanavalin A (Con A), wheat germ agglutinin (WGA), Ricinus communis agglutinin 1 (RCA-1), peanut agglutinin (PNA), and Ulex europaeus agglutinin 1 (UEA-1). Although the staining intensity with lectins was variable, tumor cells in five astrocytomas, three oligodendrogliomas, six ependymomas, and one gliosarcoma, were generally positive for Con A, WGA, and RCA-1, and negative for PNA and UEA-1, whereas those in nine glioblastomas were usually positive for Con A and WGA and negative for RCA-1 and PNA as well as UEA-1. The malignancy in neoplastic astrocytes was correlated with the decrease in binding with lectins, especially RCA-1. Blood vessels, particularly the endothelial layers, in all gliomas were stained intensely with all lectins used. Macrophages showed two staining features with lectins; stippled and granular. The former macrophages were positive for Con A, WGA, RCA-1, and PNA, and negative for UEA-1, whereas the latter macrophages were positive for all lectins used. Thus, the staining characteristics with lectins of macrophages were different from those of any glioma cells and very useful for identification of macrophages in gliomas.

Characterization of lymphoid cells isolated from human gliomas

To analyze the phenotypic profile of lymphoid cells freshly isolated from surgically resected human gliomas, a double-immunostaining technique was developed which permitted the investigators simultaneously to distinguish between hematogenous and tumor cell populations and to detect expression of lymphocyte-monocyte subset-specific antigens on hematogenous cells. With this technique, the profiles of tumor-infiltrating lymphocytes (TIL's) derived from high- and low-grade gliomas were compared with phenotypes of lymphocytes concurrently isolated from peripheral blood. The total leukocyte cell yield from high-grade glioma cases exceeded that of low-grade cases. In nine high-grade glioma cases the proportion of CD8-positive cells was increased within the TIL population (41.2% +/- 1.9%, mean +/- standard error of the mean) as compared to the corresponding peripheral blood lymphocyte (PBL) population (30.8% +/- 4.1%, p less than 0.05). The proportion of natural killer HNK-positive cells, some of which bear the CD8 antigen (although not necessarily the pan T cell antigens CD2 and CD3), was also increased in the TIL's (41.9% +/- 4.2%) compared to that found in PBL's (32.1 +/- 5.6%, p less than 0.05) of high-grade glioma cases. The observed phenotypic pattern of high-grade glioma TIL's is similar to that reported based on immunohistochemical analysis of tumor tissue sections, suggesting that the techniques described here resulted in isolation of lymphoid cells representative of TIL's.

Presence and significance of NK cells in glioblastomas

A monoclonal antibody against the surface marker IOT-10 of natural killer (NK) cells was used to investigate the presence of these cells in a series of 25 glioblastomas. In 40% of the tumors, IOT-10-positive NK cells were found in small numbers scattered among the tumor cells. The presence of IOT-10-positive NK cells was not related to the degree of lymphocytic infiltration in the tumor as demonstrated by hematoxylin and eosin staining, nor did it appear to influence the survival time of the patients studied.

The mononuclear cell infiltrate compared with survival in high-grade astrocytomas

Frozen samples from 92 malignant astrocytomas were stained with a panel of monoclonal antibodies directed against macrophages and lymphocytes. A follow-up to death was available on 68 cases which form the basis of this study. Large numbers of macrophages were found in all cases; T lymphocytes, mostly of the CD8 phenotype were also seen in moderate numbers in 70% of cases. CD4-positive cells were present in small numbers in 32% and B cells were seen in only 8% of cases. Analysis of the survival showed no demonstrable correlation between the numbers of macrophages or CD4 lymphocytes and survival. The survival curves for parenchymal CD8 infiltration diverged after 9 months suggesting increased survival for those patients without such an infiltration but the difference failed to reach statistical significance (P = 0.37). No correlation between lymphocytic cuffing and survival was seen after studying all paraffin-embedded material. We conclude that there is no significant statistical correlation between survival and the various types of mononuclear cell infiltrating malignant astrocytomas.