Multicentric reticulohistiocytosis: a rare yet challenging disease.

Multicentric reticulohistiocytosis (MRH) is a rare systemic inflammatory granulomatous disease that primarily manifests clinically with severe erosive arthritis and widespread papulonodular skin lesions but can involve multiple other organ systems. Despite the fact that this condition can become aggressive, debilitating as well as deforming with significant detrimental consequences, the etiology of this disease remains poorly understood. Moreover, the fact that MRH is such an uncommon disease has created an obstacle in the path of adequate clinical trials that are needed for better understanding of this phenomenon and for the development of treatment options for this patient population. In this review, we will attempt to discuss the epidemiology, pathophysiology, clinical features, associated conditions, differential diagnoses, diagnostic workup, and available treatments of MRH with the hope of creating a better understanding of this very challenging yet elusive disease process.

Lupus nephritis: a critical review.

Lupus nephritis remains one of the most severe manifestations of systemic lupus erythematosus associated with considerable morbidity and mortality. A better understanding of the pathogenesis of lupus nephritis is an important step in identifying more targeted and less toxic therapeutic approaches. Substantial research has helped define the pathogenetic mechanisms of renal manifestations and, in particular, the complex role of type I interferons is increasingly recognized; new insights have been gained into the contribution of immune complexes containing endogenous RNA and DNA in triggering the production of type I interferons by dendritic cells via activation of endosomal toll-like receptors. At the same time, there have been considerable advances in the treatment of lupus nephritis. Corticosteroids have long been the cornerstone of therapy, and the addition of cyclophosphamide has contributed to renal function preservation in patients with severe proliferative glomerulonephritis, though at the cost of serious adverse events. More recently, in an effort to minimize drug toxicity and achieve equal effectiveness, other immunosuppressive agents, including mycophenolate mofetil, have been introduced. Herein, we provide a detailed review of the trials that established the equivalency of these agents in the induction and/or maintenance therapy of lupus nephritis, culminating in the recent publication of new treatment guidelines by the American College of Rheumatology. Although newer biologics have been approved and continue to be a focus of research, they have, for the most part, been relatively disappointing compared to the effectiveness of biologics in other autoimmune diseases. Early diagnosis and treatment are essential for renal preservation.

Immune-mediated adverse effects of biologicals used in the treatment of rheumatic diseases.

Biological agents represent a major advance in the treatment of rheumatic diseases, most particularly in the prevention of irreversible structural damage. While generally well tolerated, their increasing use continues to reveal a variety of immune-mediated adverse effects. The most frequent adverse events are infusion reactions and injection site reactions, but despite their fairly common occurrence the precise mechanisms are not fully understood. Another adverse event that became appreciated early in the era of biologicals is the increased risk of Mycobacterium tuberculosis and other granulomatous infections in patients treated with tumor necrosis factor (TNFα) antagonists. Although it is evident that this enhanced susceptibility to intracellular infections must be due to immunosuppression arising from the blockade of TNFα, the mechanisms have not been fully elucidated; such an understanding is likely to provide important insights into the role of TNFα in granulomatous and other infectious diseases. In addition, the biologicals may paradoxically induce autoimmunity. The development of autoantibodies is seen in a considerable proportion of patients, but clinical autoimmune disease develops much less commonly, including systemic lupus erythematosus, multiple sclerosis and other demyelinating diseases, psoriasis, sarcoidosis, and interstitial lung disease. The mechanisms leading to their induction are very poorly understood, but an intriguing hypothesis is that interferon α provides a common link, at least for lupus, psoriasis and possibly sarcoidosis. Finally, the potential risk of infection with use of the biologicals is an issue that clinicians should always be aware of. These comments aside, the biologics are the most important advance in the treatment of rheumatic disease in the history of rheumatology and their usage has not only greatly helped patient care, but also provided key data on the immunobiology of the disease processes.

Currents concepts on the immunopathology of amyloidosis.

Amyloidosis is defined as the extracellular accumulation at systemic or organ-specific level of insoluble low molecular weight protein fibrils manifesting a beta pleated sheet configuration and a characteristic staining pattern. Several different types of proteins may lead to this phenomenon, and amyloidosis is defined by the biochemical nature of the protein in the deposits and further classified according to whether the deposits are localized or systemic, acquired or inherited, and by the resulting clinical phenotype. Amyloidosis includes subtypes such as light chain, associated with serum amyloid A protein, heritable and familial forms, dialysis-related disease, and organ-specific conditions. The pathogenesis and clinical features of these clinical and pathological entities will be critically discussed in this review article.

Colchicine revisited.

Purified from a Mediterranean plant nearly two centuries ago, colchicine has been discovered to inhibit many steps in the inflammatory process. The drug has good oral bioavailability and some enterohepatic recirculation, requiring dose adjustments for kidney disease and avoidance in liver disease. Toxicities are primarily gastrointestinal, hepatic, and hematologic. Colchicine is approved by the U.S. Federal Drug Administration for the treatment and prophylaxis of gout flares but has also been tried with varying success in the treatment of familial Mediterranean fever, primary biliary cirrhosis, psoriasis, Behçet's disease, aphthous stomatitis, linear IgA dermatosis, relapsing polychondritis, Sweet's syndrome, scleroderma, amyloidosis, leukocytoclastic vasculitis, epidermolysis bullosa, and dermatomyositis.

Acute rheumatic fever and its consequences: a persistent threat to developing nations in the 21st century.

Acute rheumatic fever (ARF) is an autoimmune, multi-system response secondary to molecular mimicry following Lancefield group A streptococcus (GAS) pharyngitis; it is now most commonly found in the pediatric populations of developing nations. The major source of morbidity and mortality of ARF stems from rheumatic heart disease (RHD), although the cardinal symptoms of the disease also include polyarthritis, Sydenham's chorea, subcutaneous nodules, and erythema marginatum. Therapy is aimed towards treating the initial GAS infection, using anti-inflammatory medications for acute symptoms and surgery to correct RHD. Secondary prevention is crucial, given the high risk of recurrence, and includes long-term antibiotic prophylaxis. However, vaccination towards GAS may soon be on the horizon, which may assist in both decreasing the risk of initial infection in naïve patients and helping to lower the risk of recurrence.

Revisiting Libman-Sacks endocarditis: a historical review and update.

Libman-Sacks (LS) endocarditis was first described by Libman and Sacks in 1924, and is characterized by sterile, verrucous valvular lesions with a predisposition for the mitral and aortic valves. It is now regarded as both a cardiac manifestation of systemic lupus erythematosus and, in recent years, of the antiphospholipid syndrome (APS). Though typically mild and asymptomatic, LS endocarditis can lead to significant complications, including severe valvular insufficiency requiring surgery, infective endocarditis, and thromboembolic events, such as stroke and transient ischemic events. Improvements in imaging modalities, particularly in echocardiography, have allowed better estimation of the prevalence of the disease, but further investigation is still needed into its pathogenesis, treatment, and association with APS.

Stevens-Johnson syndrome and toxic epidermal necrolysis.

Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are rare, but potentially life threatening, diseases characterized by widespread epidermal necrosis, and are predominantly medication-induced. Unfortunately, though they are often associated with long-term debilitating sequelae, there are currently no efficacious pharmaceutical interventions proven through large clinical trials. It has been well established that the epidermal damage in these diseases is due to keratinocyte apoptosis. Although drug-specific T cells are implicated in this process, our understanding of the immunopathology is far from complete. The scenario suggested by today's literature points towards drug-specific CD8+ cytotoxic T cells utilizing perforin/granzyme B trigger keratinocyte apoptosis. Subsequently, there may be an expansion of apoptosis involving the interaction of either membrane-bound or soluble Fas ligand (sFasL) with its receptor Fas. The cellular source of sFasL remains controversial, with both peripheral lymphocytes and keratinocytes themselves as potential candidates. Cytokines produced by T lymphocytes, macrophages or keratinocytes may participate by activating keratinocytes and enhancing their expression of Fas and FasL, or by promoting the skin recruitment of lymphocytes by upregulating adhesion molecules. A better understanding of the underlying immunological mechanisms is required to identify appropriate therapeutic interventions. Finally, clinicians must remain vigilant about drug hypersensitivity to prevent SJS/TEN.

The geo-epidemiology of temporal (giant cell) arteritis.

Giant cell arteritis (GCA) is the most common vasculopathy in patients over the age of 50. The majority of data on the geo-epidemiology of GCA is derived from Scandinavia, although there is very good documentation and epidemiological descriptions from studies throughout Europe and North America. There remains, however, a paucity of data on the incidence and prevalence of GCA in North American minority populations, as well as from Africa or Asia. The data that does exist suggests that the incidence of GCA is lower in Hispanic, Asian, and African American populations. It is interesting to note that as the population throughout the world continues to age, we anticipate an increased prevalence of disease based upon increases in annual incidence and improved survival. Considerable research is still needed to identify genetic, environmental, and gender-specific factors that influence not only the etiology, but also the natural history of disease.

The emergence of progressive multifocal leukoencephalopathy (PML) in rheumatic diseases.

Progressive multifocal leukoencephalopathy (PML) is a rare and devastating neurological disease with areas of demyelination in the central nervous system classically associated with profound imunosuppression. PML is caused by reactivation of latent JC virus, leading to the death of myelin-producing oligodendrocytes typically with a rapidly fatal outcome. Once seen primarily in severely immunosuppressed states including lymphoma, solid organ malignancies, and organ transplant recipients, PML became an AIDS-defining illness in the 1980s. PML has now emerged as a catastrophic illness in multiple sclerosis with biologic drug therapy (natalizumab) and reported in rheumatic diseases with and without biologic therapeutic agents. With current and future treatments that suppress and manipulate the immune system, there is risk for severe acute infections and reactivation of latent infections, such as JC virus reactivation leading to PML. It is critical, therefore, to proceed cautiously when immune system modification strategies are being evaluated for fear of unleashing undesirable or even fatal diseases. Fortunately this complication remains a rare event.

The immunobiology of systemic sclerosis.

OBJECTIVES: Systemic sclerosis (SSc) is a chronic connective tissue disease characterized by vascular damage, autoimmunity, and excessive collagen deposition. Despite advances in disease-specific treatment of other rheumatologic diseases, disease-targeted treatment in SSc continues to be elusive. In this review, our goal was to place the contemporary immunobiology of SSc in the perspective of clinical medicine. METHODS: We performed a PubMed search for the period from 1989 to 2007, using the keyword, "systemic sclerosis," resulting in a total of 9099 publications, including 1252 reviews. Articles were then selected based on their discussion of recent advances in the elusive pathogenesis of SSc. A final total of 259 articles were chosen for the review. RESULTS: The SSc hallmarks of vascular damage, immunologic activation, and collagen deposition can be traced to 4 major factors: T-cells, fibroblasts, B-cells, and cytokines/chemokines. T-cells are a major component of the infiltrate in skin and lung, exhibiting increased expression of activation markers and showing signs of antigen-driven expansion. Preliminary data indicate that induction of oral tolerance with collagen, a target of SSc T-cell responses, is associated with clinical benefits. Although this suggests that T-cells participate in the pathogenesis of SSc, their precise role and antigen specificity largely remain to be elucidated. Defective numbers and functions of certain T-cell subsets, such as natural killer and gammadelta T-cells, may be involved in the failure to maintain tolerance. Other data suggest that gammadelta T-cells may themselves be effector cells in endothelial cell cytotoxicity. There are several lines of evidence for a pathogenic role of B-cells in SSc, in particular, through the production of autoantibodies. Antibody-dependent cell-mediated cytotoxicity is a primary pathogenic event in an animal model of SSc and is likely to be involved in human SSc. Nonetheless, there is as yet no convincing evidence for the pathogenicity of SSc-specific antibodies. SSc fibroblasts exhibit a specific phenotype characterized not only by excessive collagen production but also by increased responsiveness to and production of cytokines and chemokines. This phenotype is induced by a complex network of cytokines and chemokines but appears to be maintained in the absence of exogenous stimuli via the autocrine production of some of these factors by SSc fibroblasts themselves, particularly transforming growth factor, platelet-derived growth factor, monocyte chemoattractant protein 1, and interleukin-1. CONCLUSIONS: Significant variations in laboratory data among patients suggest that the pathology reflects a heterogeneous disease. Nonetheless, the possibility of achieving clinical benefits by inducing oral tolerance highlights the importance of characterizing SSc T-cell antigens. It is hoped that the identification of some of the key players in the induction and maintenance of the SSc fibroblast phenotype may yield new disease-targeted treatment regimens for patients with SSc.

Ankylosing spondylitis: a contemporary perspective on diagnosis and treatment.

OBJECTIVES: In recent years, great progress has been made in the development of diagnostic tools, therapeutic approaches, and validated outcome measures in the understanding of the pathogenesis of ankylosing spondylitis (AS). The purpose of this review was to summarize these developments. METHODS: We performed a PubMed search for the period 1978 to 2005, using the keyword, "ankylosing spondylitis," resulting in a total of 4878 publications, including 778 reviews. Articles were then selected based on their discussion of recent diagnostic tools and new treatment approaches in the pathogenesis of AS, leading to a final total of 104 articles. RESULTS: In recent years, there have been 2 major developments in the management of AS that make earlier diagnosis possible and offer the hope of alleviating pain and preventing structural changes that result in loss of function. These developments include the use of magnetic resonance imaging to visualize the inflammatory changes in the sacroiliac joint and the axial spine, and the demonstration that tumor necrosis factor blocking agents are highly efficacious in reducing spinal inflammation and possibly in slowing radiographic progression. CONCLUSIONS: There have been major advances in both the diagnostic tools and the therapeutic regimens available for patients with AS.

Vasculitis: contemporary perspectives.

Systemic vasculitis is one of the most challenging diseases for physicians from a diagnostic perspective. Clinical symptoms vary according to blood vessel size and organ systems involved. This article outlines manifestations, diagnosis, and management of the vasculitides.

Increased CXCL8 (IL-8) expression in Multiple Sclerosis.

Multiple Sclerosis (MS) is a chronic inflammatory disease of the CNS which is characterized by large mononuclear cell infiltration and significant demyelination. CXCL8 is a chemo-attractant for both neutrophils and monocytes and triggers their firm adhesion to endothelium. In this study, we demonstrate that serum CXCL8 and CXCL8 secretion from PBMCs are significantly higher in untreated MS patients compared to controls and are significantly reduced in MS patients receiving interferon-beta1a therapy. We suggest that CXCL8 may serve as a marker of monocyte activity in MS and may play a role in monocyte recruitment to the CNS.

The use of methotrexate in rheumatoid arthritis.

OBJECTIVE: To address the long-term efficacy and toxicity issues related to methotrexate (MTX) and compare it with other disease-modifying antirheumatic drugs (DMARDs). METHODS: Review of the international literature on the clinical use of MTX in rheumatoid arthritis (RA) disease. RESULTS: MTX has emerged as a relatively safe and effective treatment for RA that compares favorably with other therapies, particularly because of its considerably longer median drug survival. The toxicity profile of MTX is well established and includes serious and sometimes fatal liver disease, pneumonitis, and cytopenias. Hence, regular and careful monitoring of patients taking MTX is essential, particularly when MTX is combined with other DMARDs. Folate supplementation can reduce some of the most common side effects of MTX, but it has not yet been established whether this translates into a reduced risk of serious disease. Another potential approach to reducing the toxicity of MTX is therapeutic drug monitoring and dose individualization. However, correlations between pharmacokinetics and clinical response have been addressed in only a few studies and with conflicting results. CONCLUSIONS: MTX is an effective DMARD with a relatively safe profile compared with other therapies. Folate supplementation can significantly reduce the risk of MTX toxicity. Finally, it is essential that patients be monitored carefully to reduce the potential serious toxicities of MTX.

B lymphocyte stimulator overexpression in patients with systemic lupus erythematosus: longitudinal observations.

OBJECTIVE: To assess the overexpression of B lymphocyte stimulator (BLyS) over time in patients with systemic lupus erythematosus (SLE). METHODS: Sixty-eight SLE patients were followed up longitudinally for a median 369 days. At each physician encounter, disease activity was assessed by the Systemic Lupus Erythematosus Disease Activity Index, and blood was collected for determination of the serum BLyS level, blood BLyS messenger RNA (mRNA) level, and cell surface BLyS expression. Twenty normal control subjects underwent similar laboratory evaluations. RESULTS: In contrast to the uniformly normal serum BLyS and blood BLyS mRNA phenotypes in control subjects, SLE patients displayed marked heterogeneity, with 50% and 61% of patients manifesting persistently or intermittently elevated serum BLyS and blood BLyS mRNA phenotypes, respectively. Surface BLyS expression by SLE peripheral blood mononuclear cells was also often increased. Treatment of patients who had elevated serum BLyS levels with intensive courses of high-dose corticosteroids resulted in marked reductions in serum BLyS levels, and tapering of the corticosteroid dosage often resulted in increases in serum BLyS levels. Serum BLyS levels generally correlated with anti-double-stranded DNA (anti-dsDNA) titers (in those with detectable anti-dsDNA titers), but changes in serum BLyS levels did not correlate with changes in disease activity in individual patients. Serum BLyS phenotype did not associate with specific organ system involvement. CONCLUSION: Dysregulation of BLyS over extended periods of time is common in patients with SLE. Neutralization of BLyS activity with an appropriate BLyS antagonist may be therapeutically beneficial.

B lymphocyte stimulator protein-associated increase in circulating autoantibody levels may require CD4+ T cells: lessons from HIV-infected patients.

To assess the helper T cell dependence of B lymphocyte stimulator (BLyS) protein-driven autoantibody production in vivo, serum levels of BLyS protein, total IgG, and anti-IgG anti-phospholipid (aPhL) autoantibodies from HIV-infected patients (n = 105) with varying degrees of CD4+ cell depletion and healthy control donors at low risk for HIV (n = 64) were determined. Peripheral blood mononuclear cells from these subjects were stained for surface expression of BLyS protein. Monocyte surface expression and serum levels of BLyS protein were increased in HIV-infected patients as were serum total IgG and IgG aPhL autoantibody levels. No associations were detected between increased serum BLyS protein levels and patient age, sex, disease duration, history of opportunistic infection or malignancy, or serum total IgG levels. However, serum levels of IgG aPhL autoantibodies were greater in patients with high serum BLyS protein levels than in those with normal serum BLyS protein levels. Importantly, this association between serum levels of BLyS protein and IgG aPhL was appreciated only in patients who were not severely CD4+ cell-depleted and not in patients who were severely CD4+ cell-depleted (peripheral blood CD4+ cell counts