A case of multicentric Castleman's disease having lung lesion successfully treated with humanized anti-interleukin-6 receptor antibody, tocilizumab

Targeting IL-6 in antibody-mediated kidney transplant rejection

Interleukin (IL)-6 is a major pro-inflammatory cytokine and central regulator of innate and adaptive immune responses. Clinical trials testing antibodies against IL-6 or its receptors have demonstrated its involvement in the pathogenesis of several autoimmune and inflammatory disorders and in the systemic inflammation and anemia associated to kidney failure and also in kidney allograft rejection. Additionally, the anti-IL-6 receptor antibody tocilizumab and the anti-IL-6 antibody clazakizumab have been studied for the treatment of naïve as well as resistant antibody-mediated kidney allograft rejection with mixed results in observational studies and early clinical development. Following promising results with a clazakizumab in a phase 2 placebo-controlled trial, a large phase 3 trial (IMAGINE) was terminated in 2024 for futility at interim analysis. Investigator-initiated clinical development continues in a smaller phase 3 trial testing tocilizumab (INTERCEPT). In this viewpoint article, we evaluate the pathophysiology of IL-6 in antibody-mediated kidney allograft rejection along with the current status of the clinical development of IL-6 targeting therapies for antibody-mediated kidney allograft rejection episodes within the wider frame of IL-6 targeting therapies in kidney failure that are considered the major causes of graft loss in kidney transplantation.

The effect of tocilizumab treatment for skin fibrosis by inhibiting CD38+ macrophages in systemic sclerosis

BACKGROUND

Dermal and pulmonary fibrosis are the main clinical symptoms of systemic scleroderma (SSc), for which there are no effective therapeutic agents. Tocilizumab is thought to improve the symptoms of fibrosis, but the effect of tocilizumab on dermal fibrosis has not been explored. This study aims to investigate the therapeutic effect of tocilizumab on skin fibrosis by inhibiting CD38+ macrophages in the bleomycin-induced SSc mice model.

METHODS

The 8-week-old BALB/c mice were randomly divided into three groups: control group (PBS group), model group (BLM group), and tocilizumab group (TCZ group). The mRNA expression of VIMENTIN, TIMP1, and COL1A1 was measured by qPCR. Western blot was used to detect the protein expression of α-SMA, TGF-β, and COL1A1 in skin tissues. The expression of CD38+ macrophages in the BLM-induced fibrosis mouse model was verified by flow cytometry and immunofluorescence.

RESULTS

In comparison to the PBS control group, mice in the BLM group showed skin fibrosis, edema, thickness, and collagen deposition. The percentage of macrophages in the skin, peripheral blood, and spleen was significantly increased in the BLM group, and the percentage of CD38+ macrophages increased in the skin and peripheral blood but decreased in the spleen. After co-cultured with macrophages, L929 fibroblasts differentiated into myofibroblasts, with increased mRNA expression of COL1A1, COL3A, TGF-β, and Fibronectin. Furthermore, after being stimulated by LPS, RAW264.7 cells showed increased expression of IL-6 and CD38. The mRNA levels of COL1A1, COL1A2, COL3A, TGF-β, and Fibronectin in L929 fibroblasts were markedly increased when co-cultured with LPS-stimulated RAW264.7 cells. Tocilizumab treatment reduced dermal thickness and collagen deposition induced by BLM. Furthermore, the percentage of total macrophages and CD38+ macrophages in the skin and peripheral blood significantly decreased after tocilizumab treatment.

CONCLUSION

This study revealed that tocilizumab improved skin fibrosis in the SSc mice model, which was mediated by inhibiting skin and peripheral CD38+ macrophages.

The changing landscape of thyroid eye disease: current clinical advances and future outlook

AIMS

This review aims to provide an overview of the current understanding of TED and its pathophysiology. To describe the evidence base for current consensus treatment recommendations and newer biological therapies available as well as to present future therapeutic research.

METHODS

We reviewed and assessed the peer-reviewed literature placing particular emphasis on recent studies evaluating the pathophysiology of TED, landmark trials forming the basis of current management and recent clinical trials informing future therapeutics. Searched were made in MEDLINE Ovid, Embase Ovid, US National Institutes of Health Ongoing Trials Register and EU Clinical Trials Register. Keywords included: "Thyroid Eye Disease", "Graves Orbitopathy", "Thyroid Orbitopathy" and "Graves' Ophthalmopathy".

RESULTS AND CONCLUSIONS

The pathophysiology of TED involves a complex array of cellular and humoral based autoimmune dysfunction. Previous therapies have been broad-based acting as a blunt instrument on this mechanism with varying efficacy but often accompanied with a significant side effect profile. The recent development of targeted therapy, spearheaded by Teprotumumab has led to an array of treatments focusing on specific components of the molecular pathway optimising their impact whilst possibly minimising their side effect profile. Future challenges involve identifying the most effective target for each patient rather than any single agent being a panacea. Long-term safety profiles will require clarification as unintended immunological consequence downstream may become manifest as seen in other diseases. Finally, future novel therapeutics will entail significant expenditure and may lead to a divergence of available treatment modalities between healthcare systems due to funding disparities.

Current developments in the diagnosis and treatment of giant cell arteritis

Giant cell arteritis is the most common vasculitis in adults above 50 years old. The disease is characterized by granulomatous inflammation of medium and large arteries, particularly the temporal artery, and is associated acutely with headache, claudication, and visual disturbances. Diagnosis of the disease is often complicated by its protean presentation and lack of consistently reliable testing. The utility of color doppler ultrasound at the point-of-care and FDG-PET in longitudinal evaluation remain under continued investigation. Novel techniques for risk assessment with Halo scoring and stratification through axillary vessel ultrasound are becoming commonplace. Moreover, the recent introduction of the biologic tocilizumab marks a paradigm shift toward using glucocorticoid-sparing strategies as the primary treatment modality. Notwithstanding these developments, patients continue to have substantial rates of relapse and biologic agents have their own side effect profile. Trials are underway to answer questions about optimal diagnostic modality, regiment choice, and duration.

Tocilizumab for giant cell arteritis

BACKGROUND

Giant cell arteritis (GCA) is the most common form of systemic vasculitis in people older than 50 years of age. It causes granulomatous inflammation of medium- to large-sized vessels. Tocilizumab is a recombinant monoclonal antibody directed against interleukin-6 receptors (IL-6R).

OBJECTIVES

To assess the effectiveness and safety of tocilizumab, given alone or with corticosteroids, compared with therapy without tocilizumab for treatment of GCA.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (which contains the Cochrane Eyes and Vision Trials Register) (2020, Issue 1); Ovid MEDLINE; Embase.com; PubMed; Latin American and Caribbean Health Science Information database (LILACS); ClinicalTrials.gov; and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP). There were no date or language restrictions in the electronic search for trials. We last searched the electronic databases on 3 January 2020.

SELECTION CRITERIA

We included only randomized controlled trials (RCTs) that compared tocilizumab of any dosage regimen (alone or with corticosteroids) with therapy without tocilizumab that had a minimum follow-up of six months. Participants were at least 50 years of age, with biopsy-proven GCA or by large-vessel vasculitis by angiography, and met the American College of Rheumatology 1990 guidelines for GCA.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methodology.

MAIN RESULTS

Main results We included two RCTs in the review. The studies were conducted in the USA, Canada, and Europe and enrolled a total of 281 participants with GCA, of whom 74% were women. The mean age of participants was 70 years, with new-onset or relapsing GCA, and fulfilled the 1990 American College of Rheumatology criteria with no uncontrolled comorbidities. Both studies were funded by F. Hoffmann-La Roche AG, the manufacturer of tocilizumab. Findings One RCT (30 participants) compared tocilizumab administered every four weeks versus placebo. Point estimates at 12 months and beyond favored tocilizumab over placebo in terms of sustained remission (risk ratio (RR) 4.25, 95% confidence interval (CI) 1.21 to 14.88; moderate-certainty evidence). Point estimates suggest no evidence of a difference for all-cause mortality at 12 months or more (RR 0.17, 95% CI 0.01 to 3.94; moderate-certainty evidence). At 12 months, mean time to first relapse after induction of remission was 25 weeks in favor of participants receiving tocilizumab compared to placebo (mean difference (MD) 25, 95% CI 11.4 to 38.6; moderate-certainty evidence). The second RCT (250 participants) randomized participants into two intervention and two comparator groups to receive tocilizumab weekly (100 participants), bi-weekly (49 participants), weekly placebo + 26-week taper (50 participants), or weekly placebo + 52-week taper (51 participants). At 12 months, point estimates from this study on proportion of participants with sustained remission favored participants who received tocilizumab weekly versus placebo + 52-week taper (RR 3.17, 95% CI 1.71 to 5.89; 151 participants); tocilizumab weekly versus placebo + 26-week taper (RR 4.00, 95% CI 1.97 to 8.12; 150 participants); tocilizumab every other week versus placebo + 52-week taper (RR 3.01, 95% CI 1.57 to 5.75; 100 participants); tocilizumab every other week versus placebo + 26-week taper (RR 3.79, 95% CI 1.82 to 7.91; 99 participants) (moderate-certainty evidence). Point estimates on proportion of participants who did not need escape therapy (defined by the study as the inability to keep to the protocol-defined prednisone taper) favored participants who received tocilizumab weekly versus placebo + 52-week taper (RR 1.71, 95% CI 1.24 to 2.35; 151 participants); tocilizumab weekly versus placebo + 26-week taper (RR 2.96, 95% CI 1.83 to 4.78; 150 participants); tocilizumab every other week versus placebo + 52-week taper (RR 1.49, 95% CI 1.04 to 2.14; 100 participants) but not tocilizumab every other week versus placebo + 26-week taper (RR 0.65, 95% CI 0.27 to 1.54; 99 participants) (moderate-certainty evidence). This study did not report mean time to first relapse after induction of remission or all-cause mortality.  Across comparison groups, the same study found no evidence of a difference  in vision changes and inconsistent evidence with regard to quality of life. Evidence on quality of life as assessed by the physical (MD 8.17, 95% CI 4.44 to 11.90) and mental (MD 5.61, 95% CI 0.06 to 11.16) component score of the 36-Item Short Form Health Survey (SF-36) favored weekly tocilizumab versus placebo + 52-week taper but not bi-weekly tocillizumab versus placebo + 26-week taper (moderate-certainty evidence). Adverse events One RCT reported a lower percentage of participants who experienced serious adverse events when receiving tocilizumab every four weeks versus placebo. The second RCT reported no evidence of a difference among groups with regard to adverse events; however, fewer participants reported serious adverse events in the tocilizumab weekly and tocilizumab biweekly interventions compared with the placebo + 26-week taper and placebo + 52-week taper comparators. Investigators in both studies reported that infection was the most frequently reported adverse event.

AUTHORS' CONCLUSIONS

This review indicates that tocilizumab therapy may be beneficial in terms of proportion of participants with sustained remission, relapse-free survival, and the need for escape therapy. While the evidence was of moderate certainty, only two studies were included in the review, suggesting that further research is required to corroborate these findings. Future trials should address issues related to the required duration of therapy, patient-reported outcomes such as quality of life and economic outcomes, as well as the clinical outcomes evaluated in this review.

Interstitial lung disease occurring shortly after tocilizumab infusion in a patient with polyarticular juvenile idiopathic arthritis: a case report

Background

Tocilizumab has been shown to be effective for treatment of juvenile idiopathic arthritis (JIA). To our knowledge, this is the first reported case of interstitial lung disease occurring shortly after tocilizumab infusion in a patient with JIA.

Case presentation

A 14-year-old female patient with polyarticular JIA developed interstitial lung disease after intravenous and subcutaneous administration of tocilizumab. Her condition improved with glucocorticoid therapy.

Conclusion

Our results suggest that increased interleukin-6 levels in the blood following tocilizumab treatment may be linked to development of interstitial lung disease.

Tocilizumab for giant cell arteritis

BACKGROUND

Giant cell arteritis (GCA) is the most common form of systemic vasculitis in people older than 50 years of age. It causes granulomatous inflammation of medium- to large-sized vessels. Tocilizumab is a recombinant monoclonal antibody directed against interleukin-6 receptors (IL-6R).

OBJECTIVES

To assess the effectiveness and safety of tocilizumab, given alone or with corticosteroids, compared with therapy without tocilizumab for treatment of GCA.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (which contains the Cochrane Eyes and Vision Trials Register) (2020, Issue 1); Ovid MEDLINE; Embase.com; PubMed; Latin American and Caribbean Health Science Information database (LILACS); ClinicalTrials.gov; and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP). There were no date or language restrictions in the electronic search for trials. We last searched the electronic databases on 3 January 2020.

SELECTION CRITERIA

We included only randomized controlled trials (RCTs) that compared tocilizumab of any dosage regimen (alone or with corticosteroids) with therapy without tocilizumab that had a minimum follow-up of six months. Participants were at least 50 years of age, with biopsy-proven GCA or by large-vessel vasculitis by angiography, and met the American College of Rheumatology 1990 guidelines for GCA.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methodology.

MAIN RESULTS

Main results We included two RCTs in the review. The studies were conducted in the USA, Canada, and Europe and enrolled a total of 281 participants with GCA, of whom 74% were women. The mean age of participants was 70 years, with new-onset or relapsing GCA, and fulfilled the 1990 American College of Rheumatology criteria with no uncontrolled comorbidities. Both studies were funded by F. Hoffmann-La Roche AG, the manufacturer of tocilizumab. Findings One RCT (30 participants) compared tocilizumab administered every four weeks versus placebo. Point estimates at 12 months and beyond favored tocilizumab over placebo in terms of sustained remission (risk ratio (RR) 4.25, 95% confidence interval (CI) 1.21 to 14.88; moderate-certainty evidence). Point estimates suggest no evidence of a difference for all-cause mortality at 12 months or more (RR 0.17, 95% CI 0.01 to 3.94; moderate-certainty evidence). At 12 months, mean time to first relapse after induction of remission was 25 weeks in favor of participants receiving tocilizumab compared to placebo (mean difference (MD) 25, 95% CI 11.4 to 38.6; moderate-certainty evidence). The second RCT (251 participants) randomized participants into two intervention and two comparator groups to receive tocilizumab weekly (100 participants), bi-weekly (49 participants), weekly placebo + 26-week taper (50 participants), or weekly placebo + 52-week taper (51 participants). At 12 months, point estimates from this study on proportion of participants with sustained remission favored participants who received tocilizumab weekly versus placebo + 52-week taper (RR 3.17, 95% CI 1.71 to 5.89; 151 participants); tocilizumab weekly versus placebo + 26-week taper (RR 4.00, 95% CI 1.97 to 8.12; 150 participants); tocilizumab every other week versus placebo + 52-week taper (RR 3.01, 95% CI 1.57 to 5.75; 100 participants); tocilizumab every other week versus placebo + 26-week taper (RR 3.79, 95% CI 1.82 to 7.91; 99 participants) (moderate-certainty evidence). Point estimates on proportion of participants who did not need escape therapy (defined by the study as the inability to keep to the protocol-defined prednisone taper) favored participants who received tocilizumab weekly versus placebo + 52-week taper (RR 1.71, 95% CI 1.24 to 2.35; 151 participants); tocilizumab weekly versus placebo + 26-week taper (RR 2.96, 95% CI 1.83 to 4.78; 150 participants); tocilizumab every other week versus placebo + 52-week taper (RR 1.49, 95% CI 1.04 to 2.14; 100 participants); tocilizumab every other week versus placebo + 26-week taper (RR 0.65, 95% CI 0.27 to 1.54; 99 participants) (moderate-certainty evidence). This study did not report mean time to first relapse after induction of remission or all-cause mortality. The same study found no evidence of a difference between groups with regard to vision changes and quality of life, except for the assessment of quality of life with the physical component score of the 36-Item Short Form Health Survey (SF-36), which favored weekly tocilizumab versus placebo + 52-week taper (MD 8.17, 95% CI 4.44 to 11.90; moderate-certainty evidence). Adverse events One RCT reported a lower percentage of participants who experienced serious adverse events when receiving tocilizumab every four weeks versus placebo. The second RCT reported no evidence of a difference among groups with regard to adverse events; however, fewer participants reported serious adverse events in the tocilizumab weekly and tocilizumab biweekly interventions compared with the placebo + 26-week taper and placebo + 52-week taper comparators. Investigators in both studies reported that infection was the most frequently reported adverse event.

AUTHORS' CONCLUSIONS

This review indicates that tocilizumab therapy may be beneficial in terms of proportion of participants with sustained remission, relapse-free survival, and the need for escape therapy. While the evidence was of moderate certainty, only two studies were included in the review, suggesting that further research is required to corroborate these findings. Future trials should address issues related to the required duration of therapy, patient-reported outcomes such as quality of life and economic outcomes, as well as the clinical outcomes evaluated in this review.

Interleukin-6: obstacles to targeting a complex cytokine in critical illness

Circulating concentrations of the pleiotropic cytokine interleukin-6 (IL-6) are known to be increased in pro-inflammatory critical care syndromes, such as sepsis and acute respiratory distress syndrome. Elevations in serum IL-6 concentrations in patients with severe COVID-19 have led to renewed interest in the cytokine as a therapeutic target. However, although the pro-inflammatory properties of IL-6 are widely known, the cytokine also has a series of important physiological and anti-inflammatory functions. An adequate understanding of the complex processes by which IL-6 signalling occurs is crucial for the correct interpretation of IL-6 concentrations in the blood or lung, the use of IL-6 as a critical care biomarker, or the design of effective anti-IL-6 strategies. Here, we outline the role of IL-6 in health and disease, explain the different types of IL-6 signalling and their contribution to the net biological effect of the cytokine, describe the approaches to IL-6 inhibition that are currently available, and discuss implications for the future use of treatments such as tocilizumab in the critical care setting.

The Clinical Characteristics and Outcomes of Follicular Bronchiolitis in Chinese Adult Patients

Follicular bronchiolitis (FB) is a rare interstitial lung disease (ILD) and has been reported in diverse clinical contexts. Six FB patients demonstrated by surgical lung biopsy (SLB) were reviewed between 2009 and 2017 from Nanjing Drum Tower Hospital in China. The average age of subjects was 42 years old (range: 31-55 years). The clinical symptoms were very mild. The laboratory findings showed elevated Erythrocyte sedimentation rate (ESR) and serum globulin and anemia. Pulmonary function tests were normal in four cases. Five cases had underlying diseases, such as, Sjo¨gren's syndrome, multi-centric castlemans' disease, idiopathic pneumonia with autoimmune features and abscess. Five cases presented as interstitial lung disease (ILD) on chest imaging with centrilobular or peribronchiolar nodules, ground glass opacities, interlobular septal thickening, cysts and bronchiectasis. Isolated mass was in one patient. The histopathology suggested the changes of FB in all subjects. Prednisone and/or cyclophosphamide were used in four cases, one did the surgery and the other was clinically monitored. All cases were alive at the end of follow up. The adult patients of FB usually have mild symptoms, ILD and underlying diseases. The definite diagnosis needs SLB. The prognosis is depended on their underlying conditions.

Tocilizumab (Actemra)

Tocilizumab (TCZ), is a recombinant humanized anti-interleukin-6 receptor (IL-6R) monoclonal antibody which has a main use in the treatment of rheumatoid arthritis, systemic juvenile idiopathic arthritis (sJIA) and polyarticular juvenile idiopathic arthritis (pJIA). This article provides an overview of TCZ including looking into the past at the discovery of interleukin-6 (IL-6) as a pro-inflammatory cytokine. It also looks at how tocilizumab was developed, manufactured and tested to ensure both safety and efficacy in a human population. The article then explores the advantages and disadvantages of using TCZ when compared to other biologics approved in RA, sJIA and pJIA and finally looks ahead to the future and the emerging role of IL-6 and its blockade by TCZ as a treatment for giant cell arteritis (GCA), polymyalgia rheumatica (PMR) and large vessel vasculitis (LVV).

Interleukin-6: an emerging regulator of pathological pain

Interleukin-6 is an inflammatory cytokine with wide-ranging biological effects. It has been widely demonstrated that neuroinflammation plays a critical role in the development of pathological pain. Recently, various pathological pain models have shown elevated expression levels of interleukin-6 and its receptor in the spinal cord and dorsal root ganglia. Additionally, the administration of interleukin-6 could cause mechanical allodynia and thermal hyperalgesia, and an intrathecal injection of anti-interleukin-6 neutralizing antibody alleviated these pain-related behaviors. These studies indicated a pivotal role of interleukin-6 in pathological pain. In this review, we summarize the recent progress in understanding the roles and mechanisms of interleukin-6 in mediating pathological pain associated with bone cancer, peripheral nerve injury, spinal cord injury, chemotherapy-induced peripheral neuropathy, complete Freund’s adjuvant injection, and carrageenan injection. Understanding and regulating interleukin-6 could be an interesting lead to novel therapeutic strategies for pathological pain.

Idiopathic multicentric Castleman's disease: a systematic literature review

BACKGROUND

Multicentric Castleman's disease describes a group of poorly understood lymphoproliferative disorders driven by proinflammatory hypercytokinaemia. Patients have heterogeneous clinical features, characteristic lymph node histopathology, and often deadly multiple organ dysfunction. Human herpesvirus 8 (HHV8) causes multicentric Castleman's disease in immunosuppressed patients. The cause of HHV8-negative multicentric Castleman's disease is idiopathic; such cases are called idiopathic multicentric Castleman's disease. An absence of centralised information about idiopathic multicentric Castleman's disease represents a major challenge for clinicians and researchers. We aimed to characterise clinical features of, treatments for, and outcomes of idiopathic multicentric Castleman's disease.

METHODS

We did a systematic literature review and searched PubMed, the Cochrane database, and ClinicalTrials.gov from January, 1995, with keywords including "Castleman's disease" and "giant lymph node hyperplasia". Inclusion criteria were pathology-confirmed Castleman's disease in multiple nodes and minimum clinical and treatment information on individual patients. Patients with HHV8 or HIV infection or diseases known to cause Castleman-like histopathology were excluded.

FINDINGS

Our search identified 626 (33%) patients with HHV8-negative multicentric Castleman's disease from 1923 cases of multicentric Castleman's disease. 128 patients with idiopathic multicentric Castleman's disease met all inclusion criteria for the systematic review. Furthermore, aggregated data for 127 patients with idiopathic multicentric Castleman's disease were presented from clinical trials, which were excluded from primary analyses because patient-level data were not available. Clinical features of idiopathic multicentric Castleman's disease included multicentric lymphadenopathy (128/128), anaemia (79/91), elevated C-reactive protein (65/79), hypergammaglobulinaemia (63/82), hypoalbuminaemia (57/63), elevated interleukin 6 (57/63), hepatomegaly or splenomegaly (52/67), fever (33/64), oedema, ascites, anasarca, or a combination (29/37), elevated soluble interleukin 2 receptor (20/21), and elevated VEGF (16/20). First-line treatments for idiopathic multicentric Castleman's disease included corticosteroids (47/128 [37%]), cytotoxic chemotherapy (47/128 [37%]), and anti-interleukin 6 therapy (11/128 [9%]). 49 (42%) of 116 patients failed first-line therapy, 2-year survival was 88% (95% CI 81-95; 114 total patients, 12 events, 36 censored), and 27 (22%) of 121 patients died by the end of their observed follow-up (median 29 months [IQR 12-50]). 24 (19%) of 128 patients with idiopathic multicentric Castleman's disease had a diagnosis of a separate malignant disease, significantly higher than the frequency expected in age-matched controls (6%).

INTERPRETATION

Our systematic review provides comprehensive information about clinical features, treatment, and outcomes of idiopathic multicentric Castleman's disease, which accounts for at least 33% of all cases of multicentric Castleman's disease. Our findings will assist with prompt recognition, diagnostic criteria development, and effective management of the disease.

FUNDING

None.

The use of monoclonal antibodies to treat Castleman’s disease

Multicentric Castleman’s disease (MCD) is a rare lymphoproliferative disorder presenting with heterogeneous clinical features and with a complex etiology. MCD incidence is increased in people living with HIV/AIDS when it is causally associated with Kaposi’s sarcoma-associated herpes virus (KSHV). HIV-seronegative individuals present with either idiopathic or KSHV-associated MCD. Central to MCD pathology is altered expression and signaling of IL-6, which promotes B-cell proliferation and causes systemic manifestations. KSHV encodes a viral homolog of human IL-6, accounting for its role in MCD, while recent evidence shows an association between IL-6 receptor polymorphisms and idiopathic MCD. The increased understanding of mechanisms underlying the pathogenesis of MCD has guided the use of new monoclonal antibody therapies for treating this complex disorder.

Multicentric Castleman's disease: a challenging diagnosis

Multicentric Castleman's disease (MCD) is a sytemic disorder with flares of non-specific symptoms suggestive of a chronic inflammatory syndrome. It is typically accompanied by generalized lymphadenopathy and multiorgan involvement. Histologically, two main variants of Castleman's disease exist, the hyalin vascular type and the plasma cell variant. Upon localization unicentric (localized), and multicentric (diffuse, systemic) subtypes can be distinguished with more different disease outcomes. Patients often exhibit acute phase reactions and several autoimmune phenomena, and are at high risk for developing malignancies. Both the idiopathic and the HHV-8-driven infectious forms of MCD represent distinct disease entities with a less favorable prognosis. The induction of human IL-6 excess via yet unknown upstream mechanisms, and overexpression of viral IL-6 by HHV-8 can pivotally influence MCD biology. Based on the role of IL-6 in pathogenesis, MCD is also designated as IL-6 lymphadenopathy. To date there are no direct therapeutic evidences, but having been translated to daily practice the main regulatory factors may serve as promising therapeutic targets.

A Case of Multicentric Castleman's Disease Presenting with Follicular Bronchiolitis

Multicentric Castleman's disease (CD) is a rare atypical lymphoproliferative disorder, which is characterized by various systemic manifestations. Some patients with multicentric CD may have concomitant lung parenchymal lesions, for which lymphoid interstitial pneumonia (LIP) is known to be the most common pathologic finding. Follicular bronchiolitis and LIP are considered to be on the same spectrum of the disease. We describe a case of multicentric CD with pulmonary involvement, which was pathologically proven as follicular bronchiolitis.