The Use of Biologic Agents in the Treatment of Ocular Manifestations of Behcet’s Disease

Behçet uveitis: Current practice and future perspectives

Described as early as Hippocrates in his “Third Book of Endemic Diseases,” Behçet's Disease (BD), also known as “The Silk Road Disease” following its initial demographics, consists of a triad of recurrent oro-genital ulcers and associated uveitis. Current demographics and rising percentages of patients seen far beyond the Silk Road in Ocular Inflammatory Disease and Uveitis Clinics list BD uveitis as one of the frontliners of non-infectious autoinflammatory eye diseases. Clinical features of BD and juvenile-onset BD are detailed alongside various approaches in classification and suggested algorithms for diagnosis that are outlined in this review. With the ongoing Human Microbiome Project and studies such as the MAMBA study, the role of the human microbiome in BD is highlighted in the pathophysiology of BD to include the current research and literature perspective. Furthermore, with the advancement of recent diagnostic and investigative techniques, especially in the field of Optical Coherence Tomography (OCT), disease-related characteristics are updated to encompass SD, EDI and OCT-angiography characteristics of BD. Having entered the era of biologic therapy, the role of various specific cytokine-blocking biologic drugs, such as TNF-α inhibitors (e.g., adalimumab, infliximab), interferon α-2a inhibitors, IL-6 and IL-1 inhibitors are presented and contrasted alongside the conventional immunosuppressant drugs and the classic old gold standard: corticosteroids (systemic or local). Finally, with the ongoing SARS-CoV-2 pandemic, it was not possible to conclude the review without reviewing the latest evidence-based literature reporting BD morbidity in this era, the observed pattern and treatment recommendations as well as those related to reported post-vaccine complications and emergence of BD.

Serum KL-6 elevation in a uveitis patient with Behçet's disease treated with adalimumab

Purpose

To report a case of uveitis with Behçet's disease in which serum levels of Krebs von den Lungen (KL)-6, a marker of interstitial lung disease, were elevated during treatment with adalimumab and returned to baseline after discontinuation of the agent.

Observations

A 67-year-old man complaining of vision disturbance was referred to our hospital. The patient had a history of recurrent episodes of bilateral uveitis and oral ulcers, and had been diagnosed with Behçet's disease. While uveitis activity was not well controlled under administration of oral prednisolone and cyclosporin, cataract of the right eye developed and required surgery. Biweekly administration of adalimumab 40 mg was therefore initiated with prednisolone at 15 mg/day. Uveitis became well controlled and cataract surgery was successfully carried out for the right eye. However, serum KL-6 gradually elevated to 1002 U/ml by 6 months after adalimumab initiation and 1277 U/ml at 9 months. Because serum KL-6 >1000 U/ml has been reported to predict interstitial lung disease, we discontinued adalimumab and started cyclosporine at 100 mg/day. Serum KL-6 gradually decreased and returned to baseline levels, no interstitial lung disease developed and exacerbation of uveitis was avoided.

Conclusions and importance

This case implies the clinical importance of monitoring serum KL-6 in patents with non-infectious uveitis being treated with adalimumab.

Behçet's disease: New insights into pathophysiology, clinical features and treatment options

Behçet's disease (BD) is a rare systemic vasculitis characterized by oral aphthous ulcers, genital ulcers, ocular lesions and other systemic manifestations. BD occurs most frequently in Eurasian populations along the ancient trading route known as the "Silk Road" which extends from eastern Asia to the Mediterranean basin. The causes of BD are unknown: it is believed to be due to an autoimmune process triggered by an infectious or environmental agent in genetically predisposed individuals. HLA-B51 allele located in the MHC locus, on chromosome 6p, has been the most strongly associated risk factor for BD in areas along the Old Silk Route. Herpes simplex virus-1 and Streptococcus have been postulated as possible environmental triggers of BD. T cell homeostasis perturbation, especially Th1 and Th17 expansion and decreased regulation by Tregs are now supposed to be the cornerstone of BD pathogenesis. The histology shows vasculitis that involves both arteries and veins, and vessels of any size. BD is a systemic vasculitis with significant neutrophil infiltration, endothelial cell swelling, and fibrinoid necrosis. The diagnosis of BD is only supported by clinical criteria and requires the exclusion of other diagnoses based on clinical presentation. There are no pathognomonic laboratorial findings of BD. This rare disease often leads to blindness and fatal systemic involvement. Main causes of death include major vessel disease and central nervous system involvement. Corticosteroids are commonly used to treat clinical manifestations of BD in combination with immunosuppressant drugs. Tumor necrosis factor (TNF)-blocking agents such as Infliximab, Etanercept, and Adalimumab have been reported to have success in patients with BD.

Long-Term Efficacy of Pegylated Interferon Alpha-2b in Behçet's Uveitis: A Small Case Series

PURPOSE

To assess the long-term efficacy and safety of pegylated interferon alpha-2b (peg-IFN-α-2b) for severe uveitis associated with Behçet's disease.

METHODS

Peg-IFN-α-2b was administrated at an initial dosage of 0,5-1,5 µg/kg/week. If any complications were observed, the dosage was tapered. Ocular examinations, systemic findings, and treatment compliance of the patients were evaluated.

RESULTS

Control of ocular inflammation was achieved in all patients (n = 4). The average increase in visual acuity after drug administration of 0,425 ± 0,125 logMAR was not statistically significant (Wilcoxon Test, p = 0,066) due to small number of cases. Any side-effects with laboratory abnormalities returned to baseline levels with reduction of the doses. Due to less frequent injections, increased satisfaction of the patients was noted.

CONCLUSIONS

This series highlights the peg-IFN-α-2b administration in Behçet's uveitis. Peg-IFN-α-2b has a potential long-term therapeutic effect for the treatment of severe uveitis. Efficacy with a reduced number of injections improved the quality of Behçet patients' lives.

Cytokine and chemokine profiles of aqueous humor and serum in horses with uveitis measured using multiplex bead immunoassay analysis

OBJECTIVE

To determine whether horses with clinically diagnosed Equine Recurrent Uveitis (ERU) and those with Leptospirosis infection have a specific cytokine profile in their aqueous humor (AH) and serum that differs from horses with uveitis secondary to other ocular inflammatory processes and from horses with normal eyes.

ANIMALS STUDIED

Twenty-five client-owned horses with uveitis that were presented to the North Carolina State University Ophthalmology Service, and four University-owned horses without history or clinical signs of ocular disease.

PROCEDURE

Samples of AH and serum were obtained from horses with ERU (n=13), acute or non-recurrent uveitis (UV; n=7), uveitis secondary to infectious keratitis (IK; n=5), and normal eyes (N; n=4). Cytokine levels in AH and serum were quantified using a multiplex bead immunoassay. Leptospiral antibody titers in serum and AH and PCR for Leptospiral DNA in AH were performed.

RESULTS

In the AH of horses with ERU, increased levels of IL-1a, IL-4, IL-6, IL-8, IL-12p70, FGF-2, G-CSF, and RANTES were measured compared to UV, IK and N eyes, but the differences were not significant. However, IL-10 was significantly higher in ERU eyes compared to IK and N (P=0.029; 0.013), and IP-10 in ERU eyes was significantly higher than in UV and N (P=0.004). Furthermore, MCP-1 was significantly higher in ERU than N (P=0.04). In the serum, increased levels of IL-1a, IL-4, IL-6, IL-8, IL-12p70, fractalkine, and G-CSF were measured in horses with ERU, but the levels were not significantly higher than those observed in UV, IK, or N horses. However, serum IP-10 levels in horses with ERU were significantly higher than in UV and N horses (P=0.005) and MCP-1 levels were significantly higher in ERU than N (P=0.03). Horses with marked ocular inflammation had significantly higher serum levels of G-CSF, IL-1a, fractalkine, IL-13, IL-4, IL-17a, IL-12p70, IFN-γ, and MCP-1. Elevated IL-10 in AH was significantly associated with disease chronicity, both overall and in ERU eyes (P=0.049), and in horses with positive ocular leptospiral titers or leptospiral PCR, significant elevations of IL-10 (P=0.0018; 0.0032) and IP-10 (P=0.0342; 0.043) were detected in the AH compared to leptospiral negative eyes.

CONCLUSIONS

The anti-inflammatory cytokine IL-10 and the pro-inflammatory cytokine IP-10 appear to play an important role in ERU. Further studies are needed to further clarify and characterize cytokine profiles of specific ocular inflammatory diseases, but multiplex bead immunoassay technology shows promise as a diagnostically valuable tool.

Progress in the understanding and utilization of biologic response modifiers in the treatment of uveitis

Uveitis is the third most common cause of blindness in developed countries. Considering the systemic and local complications of long-term corticosteroid therapy and the intolerance due to side effects and ineffectiveness of conventional chemotherapy, use of biologic response modifiers is a reasonable alternative in the treatment of non-infectious uveitis and persistent uveitic macular edema. The majority of the evidence presented here comes from open uncontrolled analyses. Based on these studies, tumor necrosis factor alpha inhibitors, especially infliximab and adalimumab, have been shown to be effective in the treatment of non-infectious uveitis in numerous studies. More research is necessary, particularly multi-center randomized clinical trials, to address the choice of biologic response modifier agent and the length of treatment as we employ biologic response modifiers in different types of uveitis and persistent uveitic macular edema.

Anti-tumor necrosis factor-α therapy in uveitis

Since the first reported use in 2001 of an anti-tumor necrosis factor-alpha (TNF-α) agent, infliximab, for the treatment of uveitis, several new anti-TNF-α agents have emerged for the treatment of refractory noninfectious uveitides, although their use remains off-label in the US. These agents have demonstrated remarkable clinical antiinflammatory efficacy and a potential immunoregulatory role in selected uveitis patients, but it is currently unclear whether they can modify the natural history of disease. We review the rationale and clinical indications for this therapy, the differences between agents, how to manage dosing and intervals, and how to screen for and identify potential side effects. We also present a summary of the science behind the use of anti-TNF-α agents in ocular inflammation and the evidence for their efficacy.

Factors affecting therapeutic decisions in intermediate and posterior uveitis

PURPOSE

To evaluate whether cost, insurance prior authorization, pregnancy considerations, and subspecialty practice lead to changes in therapeutic decisions among uveitis and retina specialists in the treatment of intermediate and posterior uveitis.

DESIGN

Prospective cross-sectional study.

METHODS

A total of 934 uveitis and retina specialists across the United States were surveyed via e-mail regarding their choice in long-term therapy for 3 hypothetical patients with uveitic conditions (Behçet disease, birdshot retinochoroiditis, and intermediate uveitis). Respondents were asked to select first- and second-choice therapies and then reselect first and second choices assuming cost of all options was equal to the patient and there would be no issues with insurance prior authorization. In 1 case, they were additionally asked for their treatment preferences if the patient desired a pregnancy. Outcomes of interest were differences in therapy choice based on cost/prior authorization, pregnancy, and subspecialty practice.

RESULTS

One hundred and six respondents (11.3%) completed the survey; 44 were uveitis specialists and 62 retina specialists. Cost and prior authorization affected the therapy choices of uveitis specialists treating ocular Behçet disease (P = .008). Uveitis specialists and retina specialists differed in their first choice in therapy for each vignette when cost and prior authorization were equalized (P = .0018, P = .0049, and P = .0156). Both uveitis specialists and retina specialists changed their therapeutic choices for intermediate uveitis when pregnancy was a consideration (P = .00001 for uveitis specialists, P = .0044 for retina specialists).

CONCLUSIONS

Physician decision making in intermediate and posterior uveitis is affected by cost and prior authorization concerns, pregnancy considerations, and subspecialty practice.

A comprehensive review and update on the biologic treatment of adult noninfectious uveitis: part II

INTRODUCTION

Treatment of adult, noninfectious uveitis remains a major challenge for ophthalmologists around the world, especially in regard to recalcitrant cases. It is reported to comprise approximately 10% of preventable blindness in the USA. The cause of uveitis can be idiopathic or associated with infectious and systemic disorders. The era of biologic medical therapies provides new options for patients with otherwise treatment-resistant inflammatory eye disease.

AREAS COVERED

This two-part review gives a comprehensive overview of the existing medical treatment options for patients with adult, noninfectious uveitis, as well as important advances for the treatment ocular inflammation. Part I covers classic immunomodulation and latest information on corticosteroid therapy. In part II, emerging therapies are discussed, including biologic response modifiers, experimental treatments and ongoing clinical studies for uveitis.

EXPERT OPINION

The hazard of chronic corticosteroid use in the treatment of adult, noninfectious uveitis is well documented. Corticosteroid-sparing therapies, which offer a very favorable risk-benefit profile when administered properly, should be substituted. Although nothing is currently approved for on-label use in this indication, many therapies, through either translation or novel basic science research, have the potential to fill the currently exposed gaps.

Anti-TNF-α therapy in patients with refractory uveitis due to Behçet's disease: a 1-year follow-up study of 124 patients

OBJECTIVE

The aim of this study was to assess the efficacy of anti-TNF-α therapy in refractory uveitis due to Behçet's disease (BD).

METHODS

We performed a multicentre study of 124 patients with BD uveitis refractory to conventional treatment including high-dose corticosteroids and at least one standard immunosuppressive agent. Patients were treated for at least 12 months with infliximab (IFX) (3-5 mg/kg at 0, 2 and 6 weeks and then every 4-8 weeks) or adalimumab (ADA) (usually 40 mg every 2 weeks). The main outcome measures were degree of anterior and posterior chamber inflammation, visual acuity, macular thickness and immunosuppression load.

RESULTS

Sixty-eight men and 56 women (221 affected eyes) were studied. The mean age was 38.6 years (s.d. 10.4). HLA-B51 was positive in 66.1% of patients and uveitis was bilateral in 78.2%. IFX was the first biologic agent in 77 cases (62%) and ADA was first in 47 (38%). In most cases anti-TNF-α drugs were used in combination with conventional immunosuppressive drugs. At the onset of anti-TNF-α therapy, anterior chamber and vitreous inflammation was observed in 57% and 64.4% of patients, respectively. In both conditions the damage decreased significantly after 1 year. At baseline, 50 patients (80 eyes) had macular thickening [optical coherence tomography (OCT) >250 μm] and 35 (49 eyes) had cystoid macular oedema (OCT>300 μm) that improved from 420 μm (s.d. 119.5) at baseline to 271 μm (s.d. 45.6) at month 12 (P < 0.01). The best-corrected visual acuity and the suppression load also showed significant improvement. After 1 year of follow-up, 67.7% of patients were inactive. Biologic therapy was well tolerated in most cases.

CONCLUSION

Anti-TNF-α therapy is effective and relatively safe in refractory BD uveitis.

Anti-TNF-alpha therapy and systemic vasculitis

TNF-α is a pleiotropic cytokine, which plays a major role in the pathogenesis of numerous autoimmune and/or inflammatory systemic diseases. Systemic vasculitis constitutes a group of rare diseases, characterized by inflammation of the arterial or venous vessel wall, causing stenosis and thrombosis. Treatment of the different type of vasculitis mainly relies on steroids and immunosuppressive drugs. In case of refractory or relapsing diseases, however, a second line of treatment may be required. Anti-TNF-α drugs have been used in this setting during the last 15 years with inconsistent results. We reviewed herein the use of anti-TNF-α therapy in different kind of vasculitis and concluded that, except for Behcet's disease, this therapeutic option has not demonstrated significant improvement in the treatment of vasculitis.

Combination therapy of infliximab and thalidomide for refractory entero-Behcet's disease: a case report

Background

Behcet's disease (BD) is a systemic inflammatory disease with the histopathological features of leukocytoclastic vasculitis that affects nearly all organs and systems. When it involves the intestine, it is called entero-Behcet's disease (entero-BD).

Case presentation

Here we described a 23-year-old man with entero-BD refractory to conventional therapies who responded well to the combination therapy of infliximab, an anti-tumor-necrosis-factor (TNF)-alpha antibody, and thalidomide. After combination treatment, the patient’s symptoms improved greatly and his Crohn's Disease Activity Index (CDAI) score decreased from 344 to 52 points, accompanied by a body weight increase from 53 kg to 64 kg. A follow-up endoscopy performed 10 weeks after the treatment showed significant improvement and the patient's multiple ulcers had healed well.

Conclusion

The combination therapy of infliximab and thalidomide appears to be clinically effective in a patient with refractory entero-BD. However, further studies need to be performed to evaluate the efficacy of this combination therapy.

Improved clinical control of a challenging case of Behçet's disease with rituximab therapy

Behçet's disease (BD) is a rare form of vasculitis in North America. Like other rare diseases, there is no high-quality evidence for biologic use beyond case reports/series, and thus, therapy remains controversial. We report on the case of a patient who failed to respond to conventional therapy with colchicine and NSAIDs. She responded to steroids but failed to tolerate steroid tapers despite azathioprine, methotrexate, infliximab, and etanercept and required chronic prednisone up to 20 mg daily due to recurrent severe mucosal ulcers with fever, erythema nodosum (EN), and arthritis. She received cyclophosphamide for another indication but even then failed steroid taper. After three courses of rituximab, she showed marked clinical improvement and was able to reduce prednisone to 8 mg and to return to school and work. A review of disease mechanisms and clinical literature is presented for those facing challenging cases where evidence is limited.

Behcet's disease with major vascular involvement

A 40-year-old Chinese man was admitted for haemoptysis and progressive deep vein thrombosis involving the inferior vena cava (IVC) despite anticoagulation. An IVC filter had been placed earlier at an outside hospital. CT angiography revealed two pulmonary artery aneurysms. The patient was found to have a history of oral and genital ulcers, uveitis and erythema nodosum, thus meeting criteria for Behçet's disease. Other causes of the haemoptysis and thrombophilia were excluded. He underwent successful coil embolisation of the pulmonary artery aneurysms and responded well to immunosuppressive therapy with cyclophosphamide and steroids. Anticoagulation was cautiously continued to limit the long-term risk of secondary thrombosis from his IVC filter. The patient remains well 5 months after initiation of immunosuppressive therapy. Making a diagnosis of Behçet's disease in the setting of thrombosis is crucial, as treatment must include immunosuppression, and, thus, fundamentally differs from the management of most other thrombotic disorders.

The future of uveitis treatment

Uveitis is a heterogeneous collection of diseases with polygenic and environmental influences. This heterogeneity presents challenges in trial design and selection of end points. Despite the multitude of causes, therapeutics targeting common inflammatory pathways are effective in treating diverse forms of uveitis. These treatments, including corticosteroids and immunomodulatory agents, although often effective, can have untoward side effects, limiting their utility. The search for drugs with equal or improved efficacy that are safe is therefore paramount. A mechanism-based approach is most likely to yield the future breakthroughs in the treatment of uveitis. We review the literature and provide examples of the nuances of immune regulation and dysregulation that can be targeted for therapeutic benefit. As our understanding of the causes of uveitis grows we will learn how to better apply antibodies designed to block interaction between inflammatory cytokines and their receptors. T-lymphocyte activation can be targeted by blocking co-stimulatory pathways or inhibiting major histocompatibility complex protein interactions. Furthermore, intracellular downstream molecules from cytokine or other pathways can be inhibited using small molecule inhibitors, which have the benefit of being orally bioavailable. An emerging field is the lipid-mediated inflammatory and regulatory pathways. Alternatively, anti-inflammatory cytokines can be provided by administering recombinant protein, and intracellular "brakes" of inflammatory pathways can be introduced potentially by gene therapy. Novel approaches of delivering a therapeutic substance include, but are not limited to, the use of small interfering RNA, viral and nonviral gene therapy, and microparticle or viscous gel sustained-release drug-delivery platforms.

Can rituximab induce long-term disease remission in patients with intra-ocular non-infectious inflammation?

Treatment of non-infectious uveitis is based primarily on the use of systemic corticosteroids and second-line immunosuppressive drugs. However, their extensive side effect profile, particularly for steroids, has led to the increased use of other immunosuppressive drugs, as sparing capacity agents. Rituximab is an anti-CD20 chimeric antibody, often given as a single course of 2 infusions, resulting in complete depletion of peripheral mature B cells. While it is licensed to treat refractory systemic lymphoma patients, it has also shown promising results in systemic auto-immune diseases, where a single course of treatment is able to achieve long-term clinical remission. Treatment with rituximab has been reported for various ocular conditions, suggesting it may be effective in inducing long-term disease control and other systemic immunosuppressive agents can be reduced or discontinued. When disease relapse occurs, a further course or courses can be given with good results. This review summarizes the current evidence regarding the role of rituximab in treating non-infectious uveitis.

Current and future treatments for Behçet's uveitis: road to remission

Behçet's disease (BD) is a multisystem inflammatory disorder of uncertain origin, although it remains defined within the spectrum of systemic immune-mediated vasculitic disorders and also represents a spectrum of putative autoimmune disease. Major symptoms include oral aphthous ulcers, genital ulcerations, skin lesions, and ocular lesions. Despite afflicting many systems, ocular complications of BD are some of the more devastating for the patient and their quality of life. Eye involvement, which affects 60-80 % of BD patients, is characterized in its more severe form by posterior or panuveitis including occlusive retinal vasculitis. While pathogenesis of BD remains complex, association with Class I MHC (HLA-B*51) predisposing to inflammation with engagement of the innate-immune system (neutrophils, NK cells), and perpetuated by the adaptive T cell responses against infectious- and/or auto-antigens. Despite the choice of conventional immunosuppressive therapies available, only recently with the advent of biologic therapy has visual prognosis and outcomes been substantially and favorably altered. For example, both interferon-α (IFN-α) and tumour necrosis factor (TNF)-α antagonists deliver promising results and for the first time improve prognosis. With IFN-α therapy, durable remissions of uveitis can be achieved and lead to drug-free remission. Similarly, anti-TNF therapy with infliximab is reported to be rapidly effective in inducing and maintaining remission. Most recently, rising evidence reports on the use of adalimumab, etanercept, and golimumab, while use of anti-interleukin (IL)-1 agents (anakinra, canakinumab, gevokizumab), IL-6 blockers (tocilizumab), and rituximab (depleting anti-CD20 antibody) is also increasing. The aim of this review is to provide evidence for the role of conventional therapies combined with evidence for advantages and disadvantages of biologic therapies in the treatment of ocular BD. Although randomized controlled trials remain sparse, evidence remains strong and enticing that biologic agents are invaluable for the treatment of sight-threatening Behçet's uveitis and makes it an exciting time for Behçet's specialists worldwide.

New approaches in immunotherapy of behçet disease

Behçet Disease (BD) is an autoimmune disorder with recurrent ocular, vascular, central nervous system, articular, mucocutaneous, and gastrointestinal manifestations with unclear etiology and pathogenesis. The further characterization of inflammatory features of Behçet's disease may eventually lead to development of better treatment options. Clinical and laboratory observations suggested an important role of IL-17, IL-21 and neutrophil-mediated process in the pathogenesis of BD. New therapeutic modalities target specific and nonspecific suppression of the immune system. The various non-specific immunosuppressive drugs, used either alone or in combinations, frequently fail to control inflammation or maintain remissions. Due to encouraging clinical results (i.e. Antigenic specification, prolonged survival with acceptable levels of toxicity); antibody-based drugs could be effective for the clinical management of Behçet's disease.

Protein therapeutics targeted at the TNF superfamily

Protein-based drugs with their unequivocal specificity achieved the long sought milestone of selectively disrupting cytokine pathways to alleviate ongoing inflammation. Tumor necrosis factor (TNF), a member of the superfamily of cytokines involved in regulating immune and inflammatory processes, provides an exemplary model of protein therapeutics. Antibody and receptor-based inhibitors of TNF modify inflammation leading to dramatic improvement in patients with certain autoimmune diseases. Collectively, the structure, specificity and valence of these protein-based drugs provide direct evidence that the essential mechanism of action is antagonism of the ligand-receptor interaction. Accumulating clinical knowledge regarding TNF inhibitors also provide insights into the mechanisms involved in different autoimmune diseases. Experience in the development of an arsenal of biologics directed at TNF has additionally contributed to knowledge toward overcoming the challenges of protein drugs, which include production, delivery, antigenicity and pharmacodynamics. Dramatic clinical outcomes with TNF inhibitors are driving investigation and development of biologics toward other members of the TNF superfamily to selectively alter functional properties of the immune system.

Development of Immunopathogenesis Strategies to Treat Behçet's Disease

Behçet disease is a chronic relapsing vasculitis with unclear etiology and immunopathogenesis. Antigenic stimuli, antigen presenting cells, T cells, monocyte, and neutrophil and endothelial cells are major parts of the pathology of the disease. Understanding of the new pathogenic mechanisms based on molecular structure of the disease helps us in improving the novel therapeutic modalities. These drugs target specific and nonspecific inhibition of the immun system. These therapies include biologic agents, new topical and systemic immunosuppressants, tolerizing agents, and immunoablation. Novel treatment will be promising to treat the especially recalcitrant cases to conventional therapy. In this paper, new aspect of the immunopathogenesis of Behçet's diseases and novel treatment modalities will be discussed.