Improvement in Castleman's disease by humanized anti-interleukin-6 receptor antibody therapy

Castleman's disease, an atypical lymphoproliferative disorder, can be classified into 2 types: hyaline-vascular and plasma cell types according to the histologic features of the affected lymph nodes. The plasma cell type is frequently associated with systemic manifestations and is often refractory to systemic therapy including corticosteroids and chemotherapy, particularly in multicentric form. Dysregulated overproduction of interleukin-6 (IL-6) from affected lymph nodes is thought to be responsible for the systemic manifestations of this disease. Therefore, interference with IL-6 signal transduction may constitute a new therapeutic strategy for this disease. We used humanized anti-IL-6 receptor antibody (rhPM-1) to treat 7 patients with multicentric plasma cell or mixed type Castleman's disease. All patients had systemic manifestations including secondary amyloidosis in 3. With the approval of our institution's ethics committee and the consent of the patients, they were treated with 50 to 100 mg rhPM-1 either once or twice weekly. Immediately after administration of rhPM-1, fever and fatigue disappeared, and anemia as well as serum levels of C-reactive protein (CRP), fibrinogen, and albumin started to improve. After 3 months of treatment, hypergammaglobulinemia and lymphadenopathy were remarkably alleviated, as were renal function abnormalities in patients with amyloidosis. Treatment was well tolerated with only transient leukopenia. Histopathologic examination revealed reduced follicular hyperplasia and vascularity after rhPM-1 treatment. The pathophysiologic significance of IL-6 in Castleman's disease was thus confirmed, and blockade of the IL-6 signal by rhPM-1 is thought to have potential as a new therapy based on the pathophysiologic mechanism of multicentric Castleman's disease. (Blood. 2000;95:56-61)     

Anti-interleukin-6 receptor antibody (tocilizumab) treatment of multicentric Castleman's disease

We report three cases of multicentric Castleman's disease (MCD) successfully treated with anti-interleukin-6 receptor antibody (tocilizumab). Tocilizumab was administered intravenously at a dose of 8 mg/kg every 2 weeks. In each case, tocilizumab alleviated symptoms, including generalized fatigue, pyrexia, and alleviated biochemical abnormalities, including anemia, hypoalbuminemia, hypergammaglobulinemia, and increased C-reactive protein (CRP). Side effects included hypercholesterolemia, acute pyelonephritis, mild inflammation of the parotid glands, and upper respiratory system inflammation. Other severe side effects were not observed. These results indicate that tocilizumab is effective for the treatment of MCD. This is the first report on tocilizumab efficacy for Castleman's disease after approval for use for Castleman's disease.     

Could toll-like receptors provide a missing link in chronic inflammation in rheumatoid arthritis? Lessons from a study on human rheumatoid tissue

In the last decade the development of a number of biological therapies has revolutionised the treatment of rheumatic diseases. The first and most widely used of these approaches, tumour necrosis factor (TNF) blockade (infliximab, entanercept, adalimumab), has now been administered to over a million patients. However, the success of these biological therapies has also highlighted their limitations. None of these treatments has shown a 100% patient response; normally responses are in the 50-70% range. As proteins, these drugs cannot be given orally and they are expensive to produce, a cost ultimately borne by the patient/health provider that can seriously limit the availability of these drugs. Lastly, these treatments, whether involving the systemic neutralisation of a cytokine (eg, TNF or IL6 receptor blockade (tocilizumab)), the ablation of a B cell population (anti-CD20, rituximab), or the potential disruption of important cellular interactions as with CTLA4-Ig (abatacept), can cause major perturbations of the immune system, the long-term effects of which are still unclear. At present, treatments such as TNF blockade can result in an increased infectious risk and the reactivation of tuberculosis can be a major issue in certain populations. As with all therapies, there is an increasing large refractory population over time. Therefore, despite the undoubted success of these therapies, there is room for improvement. Although it might be too much to expect any new treatment to affect a "cure" (all the current biological therapies require repeated administrations), there are definite gains to be made in terms of cost, oral bioavailability and a more selective interference with the immune-inflammatory response.     

Inhibition of interleukin‐6 receptor directly blocks osteoclast formation in vitro and in vivo

Objective

To investigate the efficacy of a murine anti–interleukin‐6 receptor (anti–IL‐6R) antibody in directly blocking tumor necrosis factor (TNF)– and RANKL‐mediated osteoclastogenesis in vitro and in vivo.

Methods

The efficacy of a murine antibody against IL‐6R in blocking osteoclast differentiation of mononuclear cells stimulated with RANKL was tested. In addition, arthritic human TNFα–transgenic mice were treated with anti–IL‐6R antibody, and osteoclast formation and bone erosion were assessed in arthritic paws.

Results

Blockade of IL‐6R dose dependently reduced osteoclast differentiation and bone resorption in monocyte cultures stimulated with RANKL or RANKL plus TNF. In human TNFα–transgenic mice, IL‐6R blockade did not inhibit joint inflammation, but it strongly reduced osteoclast formation in inflamed joints as well as bone erosion in vivo. Neither the cell influx into joints nor the synovial expression of IL‐6 and RANKL changed with IL‐6R blockade, while the synovial expression of IL‐1 was significantly reduced. In contrast, TNF‐mediated systemic bone loss was not inhibited by IL‐6R blockade.

Conclusion

These data suggest that blockade of IL‐6R directly affects osteoclast formation in vitro and in vivo, suggesting a direct and specific effect of anti–IL‐6R therapy on osteoclasts independently of its antiinflammatory effects. This effect adds significantly to the structure‐sparing potential of pharmacologic blockade of IL‐6R in arthritis.

     

Successful treatment of Castleman's disease with HAART in two HIV-infected patients

Castleman's disease is a heterogeneous group of lymphoproliferative disorders of unknown aetiology. Recently, human herpesvirus type 8 (HHV-8) has been associated with various diseases in individuals with HIV infection, including Kaposi's sarcoma, B cell non Hodgkin's lymphomas, and Castleman's disease.In Castleman's disease it has been hypothesized that HHV-8, encoding a number of various virokines, can be responsible for clinical manifestations of the disease.Previously, two reports have described a clinical recovery from HIV-associated Castleman's disease: by administration of a monoclonal antibody neutralizing human IL-6 in one case, and in another case by treatment with highly antiretroviral therapy and anti-herpesvirus therapy, following splenectomy. We report two cases where HAART alone led to clinical recovery from Castleman's disease.In both the cases reported here, although follow-up biopsy was not performed, it is likely that the inhibition of HHV-8 replication and of virokine release, through the restoration of immunity by HAART, was the basis for the disappearance of the clinical symptoms.     

Immunotherapeutic implication of IL-6 blockade

IL-6 is a cytokine featuring redundancy and pleiotropic activity. While IL-6 contributes to host defense against acute environmental stress, continuous IL-6 production plays a significant pathological role in various autoimmune and chronic inflammatory diseases. To counter this drawback, tocilizumab, a humanized anti-IL-6 receptor antibody, was developed. Clinical trials have verified the efficacy of tocilizumab for patients with rheumatoid arthritis, Castleman's disease and systemic juvenile idiopathic arthritis, resulting in approval of this innovative biologic for their treatment. Moreover, a considerable number of case reports and pilot studies have indicated the beneficial effects of tocilizumab on other autoimmune and chronic inflammatory diseases. Further clinical studies to evaluate the efficacy and safety of tocilizumab for these diseases are essential.     

Angiogenesis and hematopoiesis induced by Kaposi's sarcoma-associated herpesvirus-encoded interleukin-6.

Kaposi's sarcoma-associated herpesvirus (KSHV; also known as human herpesvirus 8 [HHV-8]) is a herpesvirus linked to the development of Kaposi's sarcoma (KS), primary effusion lymphoma, and a proportion of Castleman's disease. KSHV encodes viral interleukin-6 (vIL-6), which is structurally homologous to human and murine IL-6. The biological activities of vIL-6 are largely unknown. To gain insight into the biology of vIL-6, we expressed vIL-6 in murine fibroblasts NIH3T3 cells and inoculated stable vIL-6-producing clones into athymic mice. vIL-6 was detected selectively in the blood of mice injected with vIL-6-expressing clones. Compared with controls, vIL-6-positive mice displayed increased hematopoiesis in the myeloid, erythroid, and megakaryocytic lineages; plasmacytosis in spleen and lymph nodes; hepatosplenomegaly; and polyclonal hypergammaglobulinemia. vIL-6-expressing NIH3T3 cells gave rise to tumors more rapidly than did control cells, and vIL-6-positive tumors were more vascularized than controls. Vascular endothelial growth factor (VEGF) was detected at higher levels in the culture supernatant of vIL-6-expressing cells compared with controls, and immunohistochemical staining detected VEGF in spleen, lymph nodes, and tumor tissues from mice bearing vIL-6-producing tumors but not control tumors. Thus, vIL-6 is a multifunctional cytokine that promotes hematopoiesis, plasmacytosis, and angiogenesis. Through these functions, vIL-6 may play an important role in the pathogenesis of certain KSHV-associated disorders.     

Interleukin 10 deficiency attenuates induction of anti-TSH receptor antibodies and hyperthyroidism in a mouse Graves' model

Experimental Graves'-like hyperthyroidism can be induced in susceptible mouse strains by repetitive immunizations with recombinant adenovirus expressing the human full-length TSH receptor (TSHR) or its A-subunit. Previous studies have shown that splenocytes from immunized mice produce interferon (IFN)-γ and interleukin (IL) 10 in response to antigen stimulation in an in vitro T cell recall assay. Although IFN-γ is now well known to be essential for disease induction, the role(s) played by IL10 are unknown. Therefore, this study was conducted to clarify the significance of endogenous IL10 in the pathogenesis of experimental Graves' disease using IL10 deficient (IL10(-/-)) mice. Our results show that T cell response was augmented when estimated by their antigen-specific secretion of the key cytokine IFN-γ, but B cell function was dampened, that is, anti-TSHR antibody titers were decreased in IL10(-/-) mice, resulting in a lower incidence of Graves' hyperthyroidism (54% in IL10(+/+) vs 25% in IL10(-/-)). Thus, in addition to IFN-γ, these data clarified the role of IL10 for optimizing anti-TSHR antibody induction and eliciting Graves' hyperthyroidism in our Graves' mouse model.     

CD6 binds to pathogen-associated molecular patterns and protects from LPS-induced septic shock

CD6 is a lymphocyte receptor that belongs to the scavenger receptor cysteine-rich superfamily. Because some members of the scavenger receptor cysteine-rich superfamily act as pattern recognition receptors for microbial components, we studied whether CD6 shares this function. We produced a recombinant form of the ectodomain of CD6 (rsCD6), which was indistinguishable (in apparent molecular mass, antibody reactivity, and cell binding properties) from a circulating form of CD6 affinity-purified from human serum. rsCD6 bound to and aggregated several Gram-positive and -negative bacterial strains through the recognition of lipoteichoic acid and LPS, respectively. The Kd of the LPS-rsCD6 interaction was 2.69 +/- 0.32 x 10(-8) M, which is similar to that reported for the LPS-CD14 interaction. Further experiments showed that membrane CD6 also retains the LPS-binding ability, and it results in activation of the MAPK signaling cascade. In vivo experiments demonstrated that i.p. administration of rsCD6 before lethal LPS challenge significantly improved mice survival, and this was concomitant with reduced serum levels of the proinflammatory cytokines TNF-alpha, IL6, and IL-1beta. In conclusion, our results illustrate the unprecedented bacterial binding properties of rsCD6 and support its therapeutic potential for the intervention of septic shock syndrome or other inflammatory diseases of infectious origin.     

Is there a place for interferon-alpha in the treatment strategy of multicentric Castleman's disease?

INTRODUCTION: Castleman's disease is an unusual condition of unknown cause, consisting of massive proliferation of lymphoid tissue. Two forms (localized and multicentric) have been described. Interleukin-6 (IL-6) is at the core of the disease, being responsible for most of the clinical and biological signs that may be observed. Despite the benignancy of this pre-lymphoma condition, its course is usually aggressive and of poor prognosis in regard to the multicentric form. No consensus regarding treatment has been defined. Available data on the multicentric form of the disease are to scarce to allow any conclusion about the treatment timing and type of chemotherapy best suited to this condition. We report the case of a patient in whom interferon alpha (IFN-alpha) was used as first line treatment. EXEGESIS: The case of a 52-year-old man with multicentric Castleman's disease combined with high IL-6, in whom, however, testing for human herpes virus-8 proved to be negative, is described. Interferon alpha (4.5 MU/m2 three times per week during 18 months) administered as first line treatment induced dramatic improvement in the patient's general condition and normalization of the tumoral syndrome. Moreover, biological parameters and IL-6 returned to normal. Two years after interferon disruption, complete remission is still present. CONCLUSION: On the basis of the present data and those of two previous observations, anti-IL-6 and anti-infective properties of IFN-alpha are discussed. Treatment of multicentric Castleman's disease is based on corticosteroids and drugs derived from those pertaining to treatment of malignant lymphomas. Our results indicate that IFN-alpha is truly directed against Castleman's disease and has less toxicity than drugs usually prescribed. This argues for early use of IFN-alpha in Castleman's disease, in association or not with corticosteroids.     

Pathogenic significance of interleukin-6 (IL-6/BSF-2) in Castleman's disease

Castleman's disease is a syndrome consisting of giant lymph node hyperplasia with plasma cell infiltration, fever, anemia, hypergammaglobulinemia, and an increase in the plasma level of acute phase proteins. It has been reported that clinical abnormalities disappear after the resection of the affected lymph nodes, suggesting that products of lymph nodes may cause such clinical abnormalities. Interleukin-6 (IL-6) is a cytokine inducing B-cell differentiation to immunoglobulin-producing cells and regulating biosynthesis of acute phase proteins. This report demonstrates that the germinal centers of hyperplastic lymph nodes of patients with Castleman's disease produce large quantities of IL-6 without any significant production of other cytokines. In a patient with a solitary hyperplastic lymph node, clinical improvement and decrease in serum IL-6 were observed following surgical removal of the involved lymph node. There was a correlation between serum IL-6 level, lymph node hyperplasia, hypergammaglobulinemia, increased level of acute phase proteins, and clinical abnormalities. The findings in this report indicate that the generation of IL-6 by B cells in germinal centers of hyperplastic lymph nodes of Castleman's disease may be the key element responsible for the variety of clinical symptoms in this disease.     

Transgenic blockade of interleukin 6 transsignaling abrogates inflammation

The immunoregulatory cytokine interleukin6 (IL6) acts in a pro- and anti-inflammatory fashion. Synthesized by myeloid cells, fibroblasts and endothelial cells, IL6 on target cells, binds to the IL6 receptor (IL6R) and signals via complex formation with the ubiquitously expressed gp130 receptor. Paradoxically, most cells that respond to IL6 during inflammatory states do not express the IL6R and are themselves not directly responsive to the cytokine. A naturally occurring soluble form of the IL6R renders all cells responsive to IL6. This alternative signaling process is called IL6 transsignaling. Here we developed a transgenic strategy based on the overexpression of the soluble form of gp130, which specifically blocks all IL6 responses mediated by the soluble IL6R but does not affect IL6 responses via the membrane bound IL6R. In these mice, inflammatory processes are blocked as in IL6(-/-) mice, strongly arguing for a major role of the soluble IL6R during inflammation in vivo.     

Rheumatoid arthritis and periodontal disease: What are the similarities and differences?

Rheumatoid arthritis (RA) and periodontal disease (PD) are chronic inflammatory diseases that share similar osteoclasia, human leukocyte antigen‐DR4 allelic genes and immunological profile, and characteristic cytokines. Smoking can contribute to more severe RA and PD; secretion of pro‐inflammatory mediators destroys the soft synovial membrane and periodontium, respectively. Anti‐citrullinated protein antibodies and anti‐α‐enolase antibody are characteristic of these two diseases. Some studies suggest that PD may be associated with RA. Anti‐Porphyromonas gingivalis (P. gingivalis) antibody, but no P. gingivalis bacterium can be detected in RA patients’ joint fluid. Anti‐P. gingivalis antibody has been seen as a biomarker of RA. Both diseases share some nosogenesis and common pathological pathways. However, there are differing views on the connection between the two diseases. Interferon‐inducible‐16 (IFI16) is a genic marker of RA; moreover, the association between IFI16 and PD is rare. Some studies suggest PD is related to periodontal parameters and patient's pathological status rather than RA. Disease frequency in men and women differ between these two diseases. The expression of interleukin‐17 (IL‐17) receptor only associates with different genders in PD (PD of different sexes have different IL‐17 expressions). Periodontal local treatment only affects clinical periodontal status, and it does not alter circulating levels of IL‐6, tumor necrosis factor‐alpha or C‐reactive protein which are associated with RA. This review examines the similarities and differences between these two diseases and explores possible interactions. Importantly, we will discuss whether PD is a feature of RA and whether this knowledge provides helpful information in future treatment of both diseases.     

Colitis in mice lacking the common cytokine receptor gamma chain is mediated by IL-6-producing CD4+ T cells

BACKGROUND & AIMS: Mice that have a truncated mutation of the common cytokine receptor gamma chain (CR gamma -/Y) are known to spontaneously develop colitis. To identify the pathologic elements responsible for triggering this localized inflammatory disease, we elucidated and characterized aberrant T cells and their enteropathogenic cytokines in CR gamma -/Y mice with colitis. METHODS: The histologic appearance, cell population, T-cell receptor V beta usage, and cytokine production of lamina propria lymphocytes were assessed. CR gamma -/Y mice were treated with anti-interleukin (IL)-6 receptor monoclonal antibody to evaluate its ability to control colitis, and splenic CD4 + T cells from the same mouse model were adoptively transferred into SCID mice to see if they spurred the appearance of colitis. RESULTS: We found marked thickening of the large intestine, an increase in crypt depth, and infiltration of the colonic lamina propria and submucosa with mononuclear cells in the euthymic CR gamma -/Y mice, but not in the athymic CR gamma -/Y mice, starting at the age of 8 weeks. Colonic CD4 + T cells with high expressions of antiapoptotic Bcl-x and Bcl-2 were found to use selected subsets (V beta 14) of T-cell receptor and to exclusively produce IL-6. Treatment of CR gamma -/Y mice with anti-IL-6 receptor monoclonal antibody prevented the formation of colitis via the induction of apoptosis in IL-6-producing CD4 + T cells. Adoptive transfer of pathologic CD4 + T cells induced colitis in the recipient SCID mice. CONCLUSIONS: Colonic IL-6-producing thymus-derived CD4 + T cells are responsible for the development of colitis in CR gamma -/Y mice.     

Interleukin‐1 and tumor necrosis factor α blockade treatment of experimental polymyositis in mice

Objective

Histologic studies of the muscles suggest that cytokines are involved in inflammatory myopathy. The therapeutic effects of cytokine blockade are controversial, with anecdotal reports of clinical efficacy. The aim of this study was to discern the significance of interleukin‐1 (IL‐1) and tumor necrosis factor α (TNFα) as therapeutic targets in polymyositis (PM) by studying their involvement and the effects of their blockade in C protein–induced myositis (CIM), a murine model of PM.

Methods

C57BL/6 mice were immunized with recombinant skeletal C protein fragments to induce CIM. The expression of IL‐1 and TNFα in the muscles of mice with CIM was detected using immunohistochemical and real‐time polymerase chain reaction analyses. After the onset of myositis, the mice with CIM were treated with recombinant IL‐1 receptor antagonist (IL‐1Ra), anti–IL‐1R monoclonal antibody, recombinant TNF receptor (p75)–fusion protein (TNFR‐Fc), or anti‐TNFα monoclonal antibody. The muscles were examined histologically for the severity of myositis.

Results

IL‐1α– and TNFα‐positive macrophages were observed in the muscle tissue of mice with CIM as early as 7 days after immunization. IL‐1α, IL‐1β, and TNFα expression in the muscles increased as the severity of myositis peaked, at both the messenger RNA and protein levels. Continuous subcutaneous delivery of IL‐1Ra resulted in suppression of established CIM. Intermittent delivery (1‐day intervals) of anti–IL‐1R monoclonal antibody suppressed myositis, while intermittent delivery of IL‐1Ra did not suppress myositis. Treatment with anti‐TNFα monoclonal antibody and with TNFR‐Fc also reduced the severity of CIM.

Conclusion

IL‐1 and TNF blockade ameliorated CIM after disease onset and should potentially be a new strategy for the treatment of inflammatory myopathy. As IL‐1 blockade, treatment with anti–IL‐1R monoclonal antibody appeared more feasible than the other approaches.

     

Lactoferrin protects against concanavalin A‐induced liver injury in mice

Background: Liver diseases, caused by viral infection, autoimmune conditions, alcohol ingestion or the use of certain drugs, are a significant health issue, as many can develop into liver failure. Lactoferrin (Lac) is an iron‐binding glycoprotein that belongs to the transferrin family. Owing to its multiple biological functions, Lac has been evaluated in a number of clinical trials to treat infections, inflammation and cancer. Aim: The present study aims to reveal a profound hepatoprotective effect of Lac, using a mouse model of Concanavalin A (Con A)‐induced hepatitis, which mimics the pathophysiology of human viral and autoimmune hepatitis. Method: C57Bl/6J mice were injected with bovine Lac following Con A challenge. The effects of Lac on interferon (IFN)‐γ and interleukin (IL)‐4 expression were determined. The roles of Lac on T‐cell apoptosis and activation, and leukocytes infiltration were examined. Result: The data demonstrated that the protective effect of Lac was attributed to its ability to inhibit T‐cell activation and production of IFN‐γ, as well as to suppress IL‐4 production by hepatic natural killer T cells. Conclusion: These findings indicate a great therapeutic potential of Lac in treating in treating inflammatory hepatitis and possibly other inflammatory diseases.     

Anti-interleukin 6 receptor antibody tocilizumab reduces the level of serum hepcidin in patients with multicentric Castleman's disease

We report two cases of multicentric Castleman's disease (MCD) whose serum hepcidin levels were rapidly down-regulated by administration of tocilizumab, an anti- interleukin 6 (IL-6) receptor antibody. Our results indicate that IL-6-induced hepcidin over-production may be involved in the pathophysiology of microcytic anemia commonly observed in this disease.     

Antibody to human leukocyte antigen triggers endothelial exocytosis

Although antibodies to HLA play a role in the pathogenesis of diseases processes such as rejection of transplanted organs, the precise mechanisms by which antibodies cause tissue injury are not completely understood. We hypothesized that antibodies to host tissues cause inflammation in part by activating endothelial exocytosis of granules that contain prothrombotic mediators such as von Willebrand Factor (VWF) and proinflammatory mediators such as P-selectin. To test this hypothesis, we treated human endothelial cells with murine monoclonal antibody W6/32 to HLA class I and then measured exocytosis by the release of VWF and the externalization of P-selectin. Antibody to HLA activates endothelial exocytosis in a dose-dependent manner over time. The biologically active complement split product, C5a, adds a slight but significant increase to antibody induction of exocytosis. Antibody to HLA alone or with C5a did not damage the cells. Cross-linking of HLA appears to play a role in the ability of antibody to activate exocytosis, because the W6/32 monovalent Fab fragment did not activate VWF release, but the bivalent Fab'2 was effective in triggering exocytosis. To explore the in vivo effects of antibody upon graft injury, we infused W6/32 Fab'2 antibody to human HLA into severe combined immunodeficient/beige mice that had been transplanted with human skin grafts. Antibody to HLA activated exocytosis and inflammation in human skin grafts. Our data show that antibody to host antigens can activate human endothelial cell exocytosis and leukocyte trafficking. By triggering vascular inflammation, antibody activation of exocytosis may play a role in transplant rejection.     

Biologikatherapie bei rheumatologischen Erkrankungen

The analysis of cytokines (i.e. interleukins, interferons and colony-stimulating factors) has only flourished in the last 25 years subsequently revealing new insights into the pathogenesis of rheumatic diseases that revolutionised the management of patients with chronic rheumatic disorders. Tumour necrosis factor-alpha (TNF-alpha), interleukin-1 (IL-1) and interleukin-6 (IL-6) have been found to play a pivotal role in rheumatic inflammation. As early as in 1992 the first proof of concept study with a monoclonal antibody against TNF was able to demonstrate positive effects in rheumatoid arthritis. Since the approval of the first anti-TNF-alpha therapy, further agents against TNF and other proinflammatory cytokines were approved and even more biological drugs are under development aimed at modulating the disturbed immune system in patients with rheumatic diseases. To date the following biologics are approved for therapy of chronic rheumatic diseases: the TNF antagonists Etanercept, Infliximab and Adalimumab; Anakinra as an IL-1 receptor antagonist; the anti-CD20 monoclonal antibody Rituximab and the anti-CD80/86 fusion protein Abatacept. In the present article, we report on biological therapy modalities in rheumatic diseases as well as the recommendations for initiation of these agents.