Intratumoral production of IL-6 in B cell chronic lymphocytic leukemia and B lymphomas

Pla2g2a promotes innate Th2-type immunity lymphocytes to increase B1a cells

Newborns require early generation of effective innate immunity as a primary physiological mechanism for survival. The neonatal Lin28⁺Let7^– developmental pathway allows increased generation of Th2-type cells and B1a (B-1 B) cells compared to adult cells and long-term maintenance of these initially generated innate cells. For initial B1a cell growth from the neonatal to adult stage, Th2-type IL-5 production from ILC2s and NKT2 cells is important to increase B1a cells. The Th17 increase is dependent on extracellular bacteria, and increased bacteria leads to lower Th2-type generation. Secreted group IIA-phospholipase A2 (sPLA2-IIA) from the Pla2g2a gene can bind to gram-positive bacteria and degrade bacterial membranes, controlling microbiota in the intestine. BALB/c mice are Pla2g2a⁺, and express high numbers of Th2-type cells and B1a cells. C57BL/6 mice are Pla2g2a-deficient and distinct from the SLAM family, and exhibit fewer NKT2 cells and fewer B1a cells from the neonatal to adult stage. We found that loss of Pla2g2a in the BALB/c background decreased IL-5 from Th2-type ILC2s and NKT2s but increased bacterial-reactive NKT17 cells and MAIT cells, and decreased the number of early-generated B1a cells and MZ B cells and the CD4/CD8 T cell ratio. Low IL-5 by decreased Th2-type cells in Pla2g2a loss led to low early-generated B1a cell growth from the neonatal to adult stage. In anti-thymocyte/Thy-1 autoreactive μκ transgenic (ATAμκ Tg) Pla2g2a⁺ BALB/c background C.B17 mice generated NKT2 cells that continuously control CD1d⁺ B1 B cells through old aging and lost CD1d in B1 B cells generating strong B1 ATA B cell leukemia/lymphoma. Pla2g2a-deficient ATAμκTg C57BL/6 mice suppressed the initial B1a cell increase, with low/negative spontaneous leukemia/lymphoma generation. These data confirmed that the presence of Pla2g2a to control bacteria is important to allow the neonatal to adult stage. Pla2g2a promotes innate Th2-type immunity lymphocytes to increase early generated B1a cells.

Albumin-to-Fibrinogen Ratio as an Independent Prognostic Parameter in Untreated Chronic Lymphocytic Leukemia: A Retrospective Study of 191 Cases

PURPOSE

Chronic lymphocytic leukemia (CLL) is one of the most frequent type of B-cell chronic lymphoproliferative disorders and chronic inflammation takes part in the development of CLL. However, there has been no valid immune biomarker to predict the prognosis of untreated CLL patients.

Materials and Methods

In this retrospective study, we analyzed the clinical correlations and prognostic value of albumin-to-fibrinogen ratio (AFR) detected at diagnosis in 191 CLL patients.

RESULTS

The cut-off value of AFR was 9.7 calculated by X-tile. Patients who were more than 65 years old were often accompanied by low level of AFR (p < 0.001). Survival analysis showed that patients with low level of AFR had shorter overall survival (OS) than patients with high level of AFR (p < 0.001). Multivariate analysis illustrated that AFR had a negative impact on OS (p=0.003) and was independent of parameters involved in CLL international prognostic index and other prognostic markers such as CD38 and ZAP-70.

CONCLUSION

These data provide a comprehensive view of AFR and shows that AFR at diagnosis is an adverse prognostic factor in untreated CLL patients.

The STAT3 inhibitor WP1066 reverses the resistance of chronic lymphocytic leukemia cells to histone deacetylase inhibitors induced by interleukin-6

Interleukin-6 (IL-6) is a pleiotropic cytokine produced by a variety of cell types, including fibroblasts, endothelial cells, lymphocytes, and bone marrow stromal cells (BMSCs). Levels of IL-6 are increased in serum of CLL patients and correlated with adverse clinical features and short survival. In our study, we observed that IL-6 induced the resistance of CLL cells to pan-histone deacetylase (HDAC) inhibitors vorinostat (SAHA) and panobinostat (LBH589). Furthermore, low concentrations of SAHA and LBH589 enhanced the activation of the signal transducer and activator of transcription 3 (STAT3) signaling pathway induced by IL-6 in CLL cells. All of these effects were blocked by the STAT3-selective inhibitor, WP1066. Meanwhile, WP1066 decreased the expressions of Mcl-1 and Bcl-xL protein induced by IL-6 with or without low concentrations of HDAC inhibitors. Co-culture of CLL cells with BMSCs could also facilitate the activation of STAT3 and protected CLL cells from apoptosis when treated with HDAC inhibitors, and this cytoprotection was reversed by WP1066. The present study indicated that IL-6 or co-culture with BMSCs prevented HDAC inhibitor-induced apoptosis of CLL cells. This prevention was mediated by activation of the STAT3 signaling pathway. Moreover, WP1066 reversed the resistance of CLL cells to SAHA and LBH589 induced by either IL-6 or co-culture with BMSCs. Our findings suggest that targeting the STAT3 pathway may be a novel way to improve the efficacy of the HDAC inhibitor in CLL patients by overcoming antiapoptotic signaling of the microenvironment.

The "Trojan Horse" approach to tumor immunotherapy: targeting the tumor microenvironment

Most anticancer therapies including immunotherapies are given systemically; yet therapies given directly into tumors may be more effective, particularly those that overcome natural suppressive factors in the tumor microenvironment. The “Trojan Horse” approach of intratumoural delivery aims to promote immune-mediated destruction by inducing microenvironmental changes within the tumour at the same time as avoiding the systemic toxicity that is often associated with more “full frontal” treatments such as transfer of large numbers of laboratory-expanded tumor-specific cytotoxic T lymphocytes or large intravenous doses of cytokine. Numerous studies have demonstrated that intratumoural therapy has the capacity to minimizing local suppression, inducing sufficient “dangerous” tumor cell death to cross-prime strong immune responses, and rending tumor blood vessels amenable to immune cell traffic to induce effector cell changes in secondary lymphoid organs. However, the key to its success is the design of a sound rational approach based on evidence. There is compelling preclinical data for local immunotherapy approaches in tumor immunology. This review summarises how immune events within a tumour can be modified by local approaches, how this can affect systemic antitumor immunity such that distal sites are attacked, and what approaches have been proven most successful so far in animals and patients.

Interleukin-6 and its receptor in cancer: implications for translational therapeutics

Interleukin-6 (IL-6) plays a major role in the response to injury or infection and is involved in the immune response, inflammation, and hematopoiesis. Its deregulation impacts numerous disease states, including many types of cancer. Consequently, modulating IL-6 may be an innovative therapeutic strategy in several diseases. A review of relevant published literature regarding IL-6 and its receptor was performed. In addition, a review of the relevance of this cytokine system to human illness, particularly in cancer, was undertaken. IL-6 is a pleiotropic cytokine that is involved in the physiology of virtually every organ system. Aberrant expression of this cytokine has been implicated in diverse human illnesses, most notably inflammatory and autoimmune disorders, coronary artery and neurologic disease, gestational problems, and neoplasms. In cancer, high levels of circulating IL-6 are observed in almost every type of tumor studied and predict a poor outcome. Furthermore, elevated IL-6 levels are associated strongly with several of the striking phenotypic features of cancer. Several molecules have been developed recently that target the biologic function of IL-6. Early results in the clinic suggest that this strategy may have a significant salutary impact on diverse tumors. The field of cytokine research has yielded a deep understanding of the fundamental role of IL-6 and its receptor in health and disease. Therapeutic targeting of IL-6 and its receptor in cancer has strong biologic rationale, and there is preliminary evidence suggesting that targeting of the IL-6 system may be beneficial in the treatment of cancer.

Immunomodulating drugs for chronic lymphocytic leukaemia

Chronic lymphocytic leukaemia (CLL) is a malignant haematological disorder that remains mostly incurable; more than 95% of patients have disease of B-cell origin. Advances with targeted agents such as monoclonal antibodies, antisense therapy, or both these techniques combined with traditional chemotherapy have improved the frequency of remission. The clinical course of CLL is marked by frequent relapse, and there are limited therapeutic options for patients with relapsed or refractory disease. The morphologically mature CLL clone regulates the microenvironment through modulation of the cytokine milieu that aids its growth and survival, and has a role in immune escape. Targeting of the tumour-cell microenvironment has not been investigated as a treatment option for CLL. Immunomodulating agents are a new class of drugs that change expression of various cytokines and that costimulate immune effector cells.

Serum levels of IL-6 type cytokines and soluble IL-6 receptors in active B-cell chronic lymphocytic leukemia and in cladribine induced remission

We have investigated the serum concentrations of interleukin-6 (IL-6) and two IL-6 family cytokines-oncostatin M (OSM) and leukemia inhibitory factor (LIF)-in 63 patients with B-cell chronic lymphocytic leukemia (B-CLL) and 17 healthy controls using the enzyme-linked immunosorbent assay (ELISA) method. Simultaneously, we measured the serum levels of the soluble forms of two subunits of the IL-6 receptor complex-ligand binding glycoprotein 80 (sIL-6R) and glycoprotein 130 (sgp130). The cytokines and receptors were evaluated in 25 untreated patients and 38 patients treated with cladribine (2-CdA), as well as in 17 healthy controls. We have correlated the serum levels of these proteins with Rai's clinical stage of the disease, the response to 2-CdA treatment and some hematological parameters. We have also evaluated the correlation of the IL-6 serum level with the concentration of OSM and IL-6 soluble receptors. IL-6 was measurable in 62/63 (98.4%), OSM in 20/25 (80%) of untreated and 14/38 (37.8%) of the treated patients. sIL-6R and sgp130 were detectable in all 63 patients and LIF in none of the CLL patients. IL-6 serum level in untreated patients was not significantly different as compared to its concentration in the control group (P>0.05). However, in the patients treated with 2-CdA the IL-6 level was significantly lower (P<0.02), and the lowest concentration was found in the patients with complete remission (CR; median 1.4pg/ml; P<0.02). The concentration of sIL-6R was significantly higher in untreated (median 61.8 ng/ml) and treated (median 50.1 ng/ml) CLL patients when compared to normal persons (median 41.2 ng/ml; P=0.04; P<0.001, respectively). There was no difference between the sIL-6R levels in the patients with CR and the healthy controls. In non-responders sIL-6R concentration was the highest and similar to its level in the untreated patients. OSM level was higher in the untreated patients (median 1.8pg/ml) than in the normal controls (median 0.0pg/ml; P<0.001) and in the CR patients (median 0.0pg/ml; P<0.03). The serum concentration of sgp130 was similar in the untreated (median 480 pg/ml) and treated (median 470 pg/ml) patients, as well as in the healthy persons (median 420 pg/ml; P>0.05). We have found significant positive correlation between the levels of sIL-6R and the lymphocytes count in CLL patients (p=0.423; P<0.001). In addition, sIL-6R and OSM serum concentrations correlated also with CLL Rai stage. In conclusion, the serum level of IL-6, OSM and sIL-6R, but not LIF and sgp130, are useful indicators of CLL activity.

C-reactive protein serum level is a valuable and simple prognostic marker in non Hodgkin's lymphoma

Interleukin-6 plays a central role in normal B-cell maturation and in proliferation of some B-cell malignancies including multiple myeloma and some non Hodgkin's lymphomas (NHL). Furthermore, this cytokine also plays a major role in acute phase response by mediating synthesis of acute phase proteins such as C-reactive protein (CRP). In order to evaluate the exact role of CRP serum level as a simple prognostic factor, we analyzed CRP and IL-6 serum levels in 39 patients with NHL. Eleven patients had low grade NHL, 15 intermediate grade NHL, and 13 high grade NHL. Thirty percent of the patients presented detectable IL-6 serum levels (mean+/-SD: 33.6+/-95.2 U/ml, range: 0 to 500). Increased serum CRP levels were found in 42% of the patients with a mean of 29.2+/-41.97 mg/l] (range: 0 to 129). Thirty seven patients were studied for both markers. Three groups of patients were determined. One with low IL-6 and CRP serum levels (N=21), a second with high level of both markers (N=10), and the third with high serum CRP levels alone (N = 5). Only one patient had high level of serum IL-6 with no detectable CRP. The correlation of serum IL-6 and CRP levels with patient survival was investigated. Median survival in the group with low IL-6 level was not reached. 67% of patients of this group were still alive at 32 months from diagnosis. The group of patients with detectable IL-6 had a median of survival of 12 months (p<0.025). The survival of patients with a CRP<10 mg/l was not reached. 75% of patients survive at 32 months from diagnosis, whereas the group with higher CRP level reached a median survival at 8.5 months (p<0.009). As expected, on univariate analysis, there is a significant relationship between CRP and IL-6 levels (p<0.00017), and CRP levels and B symptoms (p<0.001). Furthermore there is a significant relationship between CRP and LDH levels (p<0.042).These results indicated that CRP may be considered as a valuable and easy prognostic biomarker of NHL.

Overexpanded B cell clone mediating leukemic arthritis by abundant secretion of interleukin-1beta: a case report

The role of cytokines in leukemic arthritis is unknown. The presentation of a patient with B cell chronic lymphocytic leukemia and destructive arthritis of the wrist joints prompted us to study the synovial cytokine pattern by immunohistologic analysis. In addition, rearranged V(H) and V(L) immunoglobulin genes were sequenced to assess B cell clonality. Heavy infiltrations of CD20+ cells with lambda light chain restriction were found in the synovial tissue. Sequencing demonstrated overexpansion of a single B cell clone (DP58/D/J(H)4b and IGLV3S2/Jlambda2-Jlambda3 for V(H) and V(L), respectively) in the peripheral blood. Identical V(H) and V(L) rearrangements were found in the synovial infiltrates. Somatic mutations were found in both the peripheral blood and the synovial clone. Immunohistologic study revealed the presence of abundant interleukin-1beta (IL-1beta) and, to a lesser degree, tumor necrosis factor beta (TNFbeta) (lymphotoxin). In contrast, TNFalpha, interferon-gamma, IL-4, IL-6, and IL-10 were rarely found in the synovial infiltrates. Therefore, IL-1beta secreted in great amounts by leukemic B cells appears to be the major cytokine that mediates joint destruction in leukemic arthritis.

Interleukin-6 signal transducer gp130 has specific binding sites for different cytokines as determined by antagonistic and agonistic anti-gp130 monoclonal antibodies

The cytokines interleukin (IL)-6, IL-11, ciliary neurotrophic factor (CNTF), leukemia inhibitor factor (LIF), oncostatin M (OSM) and probably the recently cloned cytokine cardiotrophin-1, signal, in combination with their specific receptors, through the common signal transducer gp130. Here, we report that the signaling activities of IL-6, IL-11, CNTF and OSM/LIF can be specifically blocked by different anti-gp130 monoclonal antibodies (mAb). Furthermore, we found two mAb, B-P8 and B-S12, which directly activate gp130 independently of the presence of cytokines or their receptors. This agonistic activity includes induction of cytokine-dependent cell proliferation and stimulation of acute-phase protein synthesis in liver cells. Compared to B-P8 mAb, the B-S12 mAb exhibited the strongest agonistic activity, while both mAb are synergistic in their action. This activity could not be blocked by inhibiting mAb against IL-6 and the IL-6 receptor. In contrast to F(ab')2 of B-S12 which still could activate gp130, Fab fragments completely lost their agonistic activity. Activation by tyrosine phosphorylation of the transcription factors Stat1 and APRF/Stat3 was also induced by B-S12 and B-P8, suggesting that both mAb induce homodimerization of gp130. Since hematopoietic stem cells express gp130 on their plasma membrane, it was anticipated that the agonistic anti-gp130 mAb could stimulate the proliferation of these stem cells. Indeed, B-S12 and B-P8 were able to stimulate CD34+ cells. In summary, our data show for the first time that mAb against gp130 can specifically block the action of distinct IL-6-type cytokines that signal through gp130. Such mAb might be of great value for therapeutic applications in diseases where a single cytokine action needs to be inhibited. In addition, the agonistic gp130 mAb may be used as growth factors for maintenance and expansion of stem cells prior to grafting.

Cytokines in the pathophysiology and treatment of chronic B-cell malignancies. A review

Chronic B-cell malignancies are characterized by accumulation of transformed B cells of low proliferative index in lymphatic and extralymphatic tissues. Cytokines do not appear to play a role in the primary step of transformation. However, proliferation as well as inhibition of apoptosis of malignant B cells can readily be explained by cytokine effects. Clinical trials of interferons (IFN) and interleukin-2 alone or in combination have been performed in patients with hairy cell leukemia (HCL), CLL, and low- and intermediate-grade non-Hodgkin's lymphoma. While IFN alpha became standard therapy of HCL, responses in other entities were variable, ranging from 0 to 70% in selected populations. Combination of IFN and cytotoxic chemotherapy in general revealed no additional benefit as compared to chemotherapy alone. Perspectives for future clinical testing of cytokines in low-grade B-cell lymphomas are discussed.