Genetically transitional disease: conceptual understanding and applicability to rheumatic disease.

In genomic medicine, the concept of genetically transitional disease (GTD) refers to cases in which gene mutation is necessary but not sufficient to cause disease. In this Perspective, we apply this novel concept to rheumatic diseases, which have been linked to hundreds of genetic variants via association studies. These variants are in the 'grey zone' between monogenic variants with large effect sizes and common susceptibility alleles with small effect sizes. Among genes associated with rare autoinflammatory diseases, many low-frequency and/or low-penetrance variants are known to increase susceptibility to systemic inflammation. In autoimmune diseases, hundreds of HLA and non-HLA genetic variants have been revealed to be modest- to moderate-risk alleles. These diseases can be reclassified as GTDs. The same concept could apply to many other human diseases. GTD could improve the reporting of genetic testing results, diagnostic yields, genetic counselling and selection of therapy, as well as facilitating research using a novel approach to human genetic diseases.

Cardiac Amyloidosis.

Amyloidosis is a pathologic and clinical condition resulting from the accumulation of insoluble aggregates of misfolded proteins in tissues. Extracellular deposition of amyloid fibrils in the myocardium leads to cardiac amyloidosis, which is often overlooked as a cause of diastolic heart failure. Although cardiac amyloidosis was previously believed to have a poor prognosis, recent advances in diagnosis and treatment have emphasized the importance of early recognition and changed management of this condition. This article provides an overview of cardiac amyloidosis and summarizes current screening, diagnosis, evaluation, and treatment options.

Genetic variations in NLRP3 and NLRP12 genes in adult-onset patients with autoinflammatory diseases: a comparative study.

Objectives: Cryopyrin-associated periodic syndrome or NLRP3-associated autoinflammatory disease (NLRP3-AID) and NLRP12-AID are both Mendelian disorders with autosomal dominant inheritance. Both diseases are rare, primarily reported in the pediatric population, and are thought to be phenotypically indistinguishable. We provide the largest cohort of adult-onset patients and compared these diseases and the gene variant frequency to population controls. Methods: A cohort of adult patients with AIDs were retrospectively studied. All underwent molecular testing for periodic fever syndrome gene panels after extensive and negative workups for systemic autoimmune and other related diseases. Patients were divided into Group 1- NLRP3-AID patients with NLRP3 variants (N=15), Group 2- NLRP12-AID with NLRP12 variants (N=14) and Group 3- both NLRP3 and NLRP12 (N=9) variants. Exome sequence data of two large control populations including the ARIC study were used to compare gene variant distribution and frequency. Results: All 38 patients were Caucasian with women accounting for 82%. Median age at diagnosis was 41 ± 23 years and the disease duration at diagnosis was 14 ± 13 years. We identified statistically significant differences between the groups, notably that gastrointestinal symptoms as well as evaluations for same were significantly more frequent in patients with NLRP12 variants, and headaches/dizziness were less common among the NLRP12 patients. Livedo reticularis was noted in four patients, exclusively among NLRP12 carriers. Over 50% of patients in Groups 1 and 2 carry low-frequency disease-associated variants, while the remaining carry rare variants. We unprecedently identified digenic variants, i.e., the coexistence of NLRP3 and NLRP12, which were either both low frequency or low frequency/rare. Allele frequencies of all variants identified in our cohort were either absent or significantly lower in the control populations, further strengthening the evidence of susceptibility of these variants to SAID phenotypes. Conclusion: Our comparative study shows that both NLRP3-AID and NLRP12-AID share similar clinical phenotypes, yet there are significant differences between them with regard to gastrointestinal and neurological symptoms. A spectrum of high to low genetic variations in both genes can contribute to SAID individually or in combination.

Inotersen Treatment for Patients with Hereditary Transthyretin Amyloidosis.

BACKGROUND: Hereditary transthyretin amyloidosis is caused by pathogenic single-nucleotide variants in the gene encoding transthyretin ( TTR) that induce transthyretin misfolding and systemic deposition of amyloid. Progressive amyloid accumulation leads to multiorgan dysfunction and death. Inotersen, a 2'- O-methoxyethyl-modified antisense oligonucleotide, inhibits hepatic production of transthyretin. METHODS: We conducted an international, randomized, double-blind, placebo-controlled, 15-month, phase 3 trial of inotersen in adults with stage 1 (patient is ambulatory) or stage 2 (patient is ambulatory with assistance) hereditary transthyretin amyloidosis with polyneuropathy. Patients were randomly assigned, in a 2:1 ratio, to receive weekly subcutaneous injections of inotersen (300 mg) or placebo. The primary end points were the change in the modified Neuropathy Impairment Score+7 (mNIS+7; range, -22.3 to 346.3, with higher scores indicating poorer function; minimal clinically meaningful change, 2 points) and the change in the score on the patient-reported Norfolk Quality of Life-Diabetic Neuropathy (QOL-DN) questionnaire (range, -4 to 136, with higher scores indicating poorer quality of life). A decrease in scores indicated improvement. RESULTS: A total of 172 patients (112 in the inotersen group and 60 in the placebo group) received at least one dose of a trial regimen, and 139 (81%) completed the intervention period. Both primary efficacy assessments favored inotersen: the difference in the least-squares mean change from baseline to week 66 between the two groups (inotersen minus placebo) was -19.7 points (95% confidence interval [CI], -26.4 to -13.0; P<0.001) for the mNIS+7 and -11.7 points (95% CI, -18.3 to -5.1; P<0.001) for the Norfolk QOL-DN score. These improvements were independent of disease stage, mutation type, or the presence of cardiomyopathy. There were five deaths in the inotersen group and none in the placebo group. The most frequent serious adverse events in the inotersen group were glomerulonephritis (in 3 patients [3%]) and thrombocytopenia (in 3 patients [3%]), with one death associated with one of the cases of grade 4 thrombocytopenia. Thereafter, all patients received enhanced monitoring. CONCLUSIONS: Inotersen improved the course of neurologic disease and quality of life in patients with hereditary transthyretin amyloidosis. Thrombocytopenia and glomerulonephritis were managed with enhanced monitoring. (Funded by Ionis Pharmaceuticals; NEURO-TTR ClinicalTrials.gov number, NCT01737398 .).

The Complement System and C1q in Chronic Hepatitis C Virus Infection and Mixed Cryoglobulinemia.

The complement system bridges innate and adaptive immunity against microbial infections, with viral infection being a major trigger. Activation of the classical, alternative, and lectin pathways have been reported in chronic hepatitis C virus (HCV) infection and/or cryoglobulinemia. HCV infection leads to dysregulation of complement-mediated immune responses. Clinical and experimental evidence support involvement of complement in intra- and extrahepatic manifestations of HCV infection, such as liver fibrosis and type II cryoglobulinemia. In this review, we summarize studies that have investigated the interplay between HCV and the complement system to establish chronic infection and autoimmunity, as well as the association between HCV pathogenesis and abnormal complement profiles. Several unanswered questions are highlighted which suggest additional informative lines of investigation.

Repurposing diflunisal for familial amyloid polyneuropathy: a randomized clinical trial.

IMPORTANCE: Familial amyloid polyneuropathy, a lethal genetic disease caused by aggregation of variant transthyretin, induces progressive peripheral nerve deficits and disability. Diflunisal, a nonsteroidal anti-inflammatory agent, stabilizes transthyretin tetramers and prevents amyloid fibril formation in vitro. OBJECTIVE: To determine the effect of diflunisal on polyneuropathy progression in patients with familial amyloid polyneuropathy. DESIGN, SETTING, AND PARTICIPANTS: International randomized, double-blind, placebo-controlled study conducted among 130 patients with familial amyloid polyneuropathy exhibiting clinically detectable peripheral or autonomic neuropathy at amyloid centers in Sweden (Umeå), Italy (Pavia), Japan (Matsumoto and Kumamoto), England (London), and the United States (Boston, Massachusetts; New York, New York; and Rochester, Minnesota) from 2006 through 2012. INTERVENTION: Participants were randomly assigned to receive diflunisal, 250 mg (n=64), or placebo (n=66) twice daily for 2 years. MAIN OUTCOMES AND MEASURES: The primary end point, the difference in polyneuropathy progression between treatments, was measured by the Neuropathy Impairment Score plus 7 nerve tests (NIS+7) which ranges from 0 (no neurological deficits) to 270 points (no detectable peripheral nerve function). Secondary outcomes included a quality-of-life questionnaire (36-Item Short-Form Health Survey [SF-36]) and modified body mass index. Because of attrition, we used likelihood-based modeling and multiple imputation analysis of baseline to 2-year data. RESULTS: By multiple imputation, the NIS+7 score increased by 25.0 (95% CI, 18.4-31.6) points in the placebo group and by 8.7 (95% CI, 3.3-14.1) points in the diflunisal group, a difference of 16.3 points (95% CI, 8.1-24.5 points; P < .001). Mean SF-36 physical scores decreased by 4.9 (95% CI, -7.6 to -2.2) points in the placebo group and increased by 1.5 (95% CI, -0.8 to 3.7) points in the diflunisal group (P < .001). Mean SF-36 mental scores declined by 1.1 (95% CI, -4.3 to 2.0) points in the placebo group while increasing by 3.7 (95% CI, 1.0-6.4) points in the diflunisal group (P = .02). By responder analysis, 29.7% of the diflunisal group and 9.4% of the placebo group exhibited neurological stability at 2 years (<2-point increase in NIS+7 score; P = .007). CONCLUSIONS AND RELEVANCE: Among patients with familial amyloid polyneuropathy, the use of diflunisal compared with placebo for 2 years reduced the rate of progression of neurological impairment and preserved quality of life. Although longer-term follow-up studies are needed, these findings suggest benefit of this treatment for familial amyloid polyneuropathy. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT00294671.

Rheumatoid factor, complement, and mixed cryoglobulinemia.

Low serum level of complement component 4 (C4) that occurs in mixed cryoglobulinemia (MC) may be due to in vivo or ex vivo activation of complement by the classical pathway. Potential activators include monoclonal IgM rheumatoid factor (RF), IgG antibodies, and the complexing of the two in the cold, perhaps modulated by the rheology and stoichiometry of cryocomplexes in specific microcirculations. There is also the potential for activation of complement by the alternative and lectin pathways, particularly in the setting of chronic infection and immune stimulation caused by hepatitis C virus (HCV). Engagement of C1q and interaction with specific cell surface receptors serve to localize immune complexes (ICs) to the sites of pathology, notably the cutaneous and glomerular microcirculations. Defective or saturated clearance of ICs by CR1and/or Fc receptors may explain persistence in the circulation. The phlogistic potential of cryoprecipitable ICs depends upon the cleavage of complement components to generate fragments with anaphylatoxin or leukocyte mobilizing activity, and the assembly of the membrane attack complex (C5b-9) on cell surfaces. A research agenda would include further characterization of the effector arm of complement activation in MC, and elucidation of activation mechanisms due to virus and viral antigens in HCV infection.

Diagnostic performance of amyloid A protein quantification in fat tissue of patients with clinical AA amyloidosis.

OBJECTIVE: Amyloid A protein quantification in fat tissue is a new immunochemical method for detecting AA amyloidosis, a rare but serious disease. The objective was to assess diagnostic performance in clinical AA amyloidosis. METHODS: Abdominal subcutaneous fat tissue of patients with AA amyloidosis was studied at the start of an international clinical trial with eprodisate (NC-503; 1,3-propanedisulfonate; Kiacta), an antiamyloid compound. All patients had renal findings, i.e. proteinuria (> or =1 g/day) or reduced creatinine clearance (20 - 60 ml/min). Controls were patients with other types of amyloidosis and arthritic patients without amyloidosis. Amyloid A protein was quantified by ELISA using monoclonal antihuman serum amyloid A antibodies. Congo red stained slides were scored by light microscopy in a semiquantitative way (0 to 4+). RESULTS: Ample fat tissue (>50 mg) was available for analysis in 154 of 183 patients with AA amyloidosis and in 354 controls. The sensitivity of amyloid A protein quantification for detection of AA amyloidosis (>11.6 ng/mg fat tissue) was 84% (95% CI: 77 - 89%) and specificity 99% (95% CI: 98 - 100%). Amyloid A protein quantification and semiquantitative Congo red scoring were concordant. Men had lower amyloid A protein values than women (p < 0.0001) and patients with familial Mediterranean fever had lower values than patients with arthritis (p < 0.001) or other inflammatory diseases (p < 0.01). CONCLUSIONS: Amyloid A protein quantification in fat tissue is a sensitive and specific method for detection of clinical AA amyloidosis. Advantages are independence from staining quality and observer experience, direct confirmation of amyloid AA type, and potential for quantitative monitoring of tissue amyloid over time.

Eprodisate for the treatment of renal disease in AA amyloidosis.

BACKGROUND: Amyloid A (AA) amyloidosis is a complication of chronic inflammatory conditions that develops when proteolytic fragments of serum amyloid A protein (SAA) are deposited in tissues as amyloid fibrils. Amyloid deposition in the kidney causes progressive deterioration in renal function. Eprodisate is a member of a new class of compounds designed to interfere with interactions between amyloidogenic proteins and glycosaminoglycans and thereby inhibit polymerization of amyloid fibrils and deposition of the fibrils in tissues. METHODS: We performed a multicenter, randomized, double-blind, placebo-controlled trial to evaluate the efficacy and safety of eprodisate in patients with AA amyloidosis and kidney involvement. We randomly assigned 183 patients from 27 centers to receive eprodisate or placebo for 24 months. The primary composite end point was an assessment of renal function or death. Disease was classified as worsened if any one of the following occurred: doubling of the serum creatinine level, reduction in creatinine clearance by 50% or more, progression to end-stage renal disease, or death. RESULTS: At 24 months, disease was worsened in 24 of 89 patients who received eprodisate (27%) and 38 of 94 patients given placebo (40%, P=0.06); the hazard ratio for worsening disease with eprodisate treatment was 0.58 (95% confidence interval, 0.37 to 0.93; P=0.02). The mean rates of decline in creatinine clearance were 10.9 and 15.6 ml per minute per 1.73 m(2) of body-surface area per year in the eprodisate and the placebo groups, respectively (P=0.02). The drug had no significant effect on progression to end-stage renal disease (hazard ratio, 0.54; P=0.20) or risk of death (hazard ratio, 0.95; P=0.94). The incidence of adverse events was similar in the two groups. CONCLUSIONS: Eprodisate slows the decline of renal function in AA amyloidosis. (ClinicalTrials.gov number, NCT00035334.)

In normal rat, intraventricularly administered insulin-like growth factor-1 is rapidly cleared from CSF with limited distribution into brain.

BACKGROUND: Putatively active drugs are often intraventricularly administered to gain direct access to brain and circumvent the blood-brain barrier. A few studies on the normal central nervous system (CNS) have shown, however, that the distribution of materials after intraventricular injections is much more limited than presumed and their exit from cerebrospinal fluid (CSF) is more rapid than generally believed. In this study, we report the intracranial distribution and the clearance from CSF and adjacent CNS tissue of radiolabeled insulin-like growth factor-1 after injection into one lateral ventricle of the normal rat brain. METHODS: Under barbiturate anesthesia, 125I-labeled insulin-like growth factor-1 (IGF-1) was injected into one lateral ventricle of normal Sprague-Dawley rats. The subsequent distribution of IGF-1 through the cerebrospinal fluid (CSF) system and into brain, cerebral blood vessels, and systemic blood was measured over time by gamma counting and quantitative autoradiography (QAR). RESULTS: Within 5 min of infusion, IGF-1 had spread from the infused lateral ventricle into and through the third and fourth ventricles. At this time, 25% of the infused IGF-1 had disappeared from the CSF-brain-meningeal system; the half time of this loss was 12 min. The plasma concentration of cleared IGF-1 was, however, very low from 2 to 9 min and only began to rise markedly after 20 min. This delay between loss and gain plus the lack of radiotracer in the cortical subarachnoid space suggested that much of the IGF-1 was cleared into blood via the cranial and/or spinal nerve roots and their associated lymphatic systems rather than periventricular tissue and arachnoid villi. Less than 10% of the injected radioactivity remained in the CSF-brain system after 180 min. The CSF and arteries and arterioles within the subarachnoid cisterns were labeled with IGF-1 within 10 min. Between 60 and 180 min, most of the radioactivity within the cranium was retained within and around these blood vessels and by periaqueductal gray matter. Tissue profiles at two sites next to ventricular CSF showed that IGF-1 penetrated less than 1.25 mm into brain tissue and appreciable 125I-activity remained at the tissue-ventricular CSF interface after 180 min. CONCLUSION: Our findings suggest that entry of IGF-1 into normal brain parenchyma after lateral ventricle administration is limited by rapid clearance from CSF and brain and slow movement, apparently by diffusion, into the periventricular tissue. Various growth factors and other neuroactive agents have been reported to be neuroprotective within the injured brain after intraventricular administration. It is postulated that the delivery of such factors to neurons and glia in the injured brain may be facilitated by abnormal CSF flow. These several observations suggest that the flow of CSF and entrained solutes may differ considerably between normal and abnormal brain and even among various neuropathologies.

Rheumatologic illnesses: treatment strategies for older adults.

Basic objectives of arthritis therapy are to reduce musculoskeletal pain, slow progression of disease, maintain and improve function and quality of life, and avoid adverse drug reactions. Both nonpharmacologic and pharmacologic approaches may be taken. The former include patient education, cognitive therapy, high-intensity progressive-resistance or strength training, weight control, cold therapy, heat, massage, relaxation and distraction techniques. Guiding principles for the pharmacologic management of musculoskeletal disease in geriatric patients are to 'start low and go slow,' and to provide adequate pain relief. The latter may include the use of topicals, such as 5% lidocaine patches or capsaicin, or orally administered analgesics, such as acetaminophen, tramadol, nonsteroidal anti-inflammatory drugs (NSAIDs), and opiates. Although attractive because of the reduced incidence of serious gastrointestinal adverse reactions, selective COX-2 inhibitors may have significant renal and cardiovascular toxicities, and thus should be used with caution in the older patient with co-morbid diseases affecting these organs. Intraarticular therapies with corticosteroids, or as viscosupplementation, may have a role in the management of osteoarthritis. For patients with inflammatory arthropathies, low-dose systemic steroids or disease-modifying agents are therapeutic. When therapy fails and pain remains intolerable or disabling, surgical options may be considered.

Geriatric autoimmune diseases: systemic lupus erythematosus, Sjogren's syndrome, and myositis.

Systemic lupus erythematosus (SLE), Sjogren's syndrome (SS), and dermatomyositis (DM)/polymyositis (PM) may be encountered in geriatric patients due to improved survival rates in patients with younger ages of onset or from elderly-onset (EO) disease. EO disease accounts for up to 20% of patients affected by these disorders, and is typically insidious rather than acute. Whereas SS and DM/PM are considered autoimmune diseases with distinct organ specificity, SLE is a systemic disorder that may affect multiple organ systems. Commonly used clinical and laboratory criteria for defining and diagnosing these diseases were largely developed for patients age <65, and need to be modified in the geriatric patient. Therapeutic strategies include attention to ongoing drug regimens, medical comorbidities, and the roles of fatigue, depression, and arthropathy. Each disease may be responsive to low-dose corticosteroids, with a role for first or second-line immunosuppressives as steroid-sparing agents.

Crystal arthritis. Gout and pseudogout in the geriatric patient.

Gout and pseudogout are inflammatory arthritides due to monosodium urate and calcium pyrophosphate dihydrate crystal formation. Both are prevalent among geriatric patients, and can present as acute mono- or oligoarticular disease, or as a chronic polyarthropathy resembling osteoarthritis or rheumatoid arthritis. Gout in the geriatric patient is a disease affecting women, commonly associated with diuretic usage, often involves the fingers, may be complicated by the development of masses of uric acid crystals (tophi) in soft tissues, and is frequently polyarticular. Pseudogout in the geriatric patient has a variety of clinical presentations, may be acute or chronic, and should be considered in evaluating any patient with osteoarthritis occurring in an atypical distribution. Treatment includes the use of nonsteroidal anti-inflammatory drugs, colchicine, or corticosteroids. Gout may be impacted by dietary factors, weight reduction, and avoidance of certain forms of alcohol; uric acid-lowering agents are effective for refractory or chronic tophaceous disease.

Osteoarthritis. A review of musculoskeletal aging and treatment issues in geriatric patients.

Musculoskeletal disease is extraordinarily prevalent among geriatric patients, with an incidence that is increasing with the growth of this segment of the population. It is a major cause of disability, dependency, dysmobility, pain, and depression. Rheumatologic evaluation of the geriatric patient provides challenges to the clinician in the proper interpretation of pain, the effect of comorbidities and multiple medications, and the need to consider an interdisciplinary approach that includes the recognition of cognitive deficits, functional evaluations, and treatment of muscle atrophy. Osteoarthritis accounts for 60% to 70% of joint disease in older persons, with pathologic and radiographic findings that are a "background" against which to consider pain and limitation of motion. Therapeutic strategies that incorporate reconditioning, the reduction of load-bearing, and adequate pain control may positively impact quality of life and reduce the potential for falls.

Autoimmune disease complicating antiviral therapy for hepatitis C virus infection.

OBJECTIVE: To review autoimmune disease complicating therapy with type I interferons (IFNs), specifically in the setting of hepatitis C virus (HCV) infection. METHODS: This study describes 13 reported cases of drug-induced systemic lupus erythematosus (SLE) associated with IFN therapy for the period reported during 1990-2002 by searching MEDLINE. In addition, 2 additional patients are presented, 1 with SLE and 1 with an antineutrophil cytoplasmic antibody (ANCA)-positive nephritis, with long-term follow-up. RESULTS: Of 13 cases of SLE-like syndromes caused by IFN, 2 occurred in patients being treated for HCV infection. Two occurred in patients with rheumatoid arthritis (RA); 1 had Sjogren's syndrome (SS), and 1 laryngeal papillomatosis. The rest were receiving IFN for hematologic malignancies. Symptoms developed between 2 weeks and 7 years after initiation of therapy. Most developed fever and arthralgias/arthritis. Other findings included serositis manifested by tachycardia, dyspnea and pleural effusions, headaches, and hair loss. All had a positive antinuclear antibody (ANA), and the majority had double stranded (ds) DNA antibodies. Two additional patients with chronic HCV infection developed autoimmune disease after combination treatment with IFN-alpha and ribavirin. In each patient, autoimmune disease manifested as severe joint pains, myalgias, fever, rash, and proteinuria. Skin and renal biopsy specimens showed vasculitis and crescentic glomerulonephritis (GN) in the first case, and typical histologic findings of lupus nephritis in the second; clinical and laboratory features were consistent with Wegener's granulomatosis and SLE, respectively. Although both patients had mixed polyclonal cryoglobulins, they were HCV RNA and HCVAb negative. Both received corticosteroids, with gradual clinical and biochemical improvement and without recurrence of viremia. CONCLUSIONS: Autoimmune disorders occur in 4% to 19% of patients receiving IFN-alpha, though SLE-like syndromes are only seen in 0.15% to 0.7%. Clinical and laboratory features of SLE in this setting resemble idiopathic disease, with a generally good outcome after discontinuance of the drug. RELEVANCE: Type I IFNs may cause autoimmune disease such as SLE. As the armamentarium of drugs expands to include other biologics, such as the tumor necrosis factor (TNF)-alpha-inhibiting drugs, the development of autoimmune diseases induced by these drugs is an important consideration for diagnosis and appropriate treatment. Semin Arthritis Rheum 32:163-173.