Faculty Bibliography

Osteoarthritis (OA) is often a progressive and disabling disease resulting from a combination of risk factors, including age, genetics, trauma, and knee alignment, as well as an imbalance of physiologic processes resulting in inflammatory cascades on a molecular level. The synovium, bone, and cartilage are each involved in the pathophysiological mechanisms that lead to progressive joint degeneration, and, thus, also serve as targets for therapies. Efforts to identify disease-modifying osteoarthritis drugs (DMOADs) have been hampered by several factors, but the focus has now shifted toward the validation of chemical and imaging biomarkers that should aid in DMOAD development. In this review, we summarize current pathological mechanisms occurring in the individual but interconnected compartments of OA joints, as well as discuss related therapeutic interventions that are currently available or on the horizon

Biologic therapies have emerged as important treatments in chronic inflammatory diseases, such as rheumatoid arthritis and inflammatory bowel disease, and are now garnering more attention in the vasculitides. These agents, including tumor necrosis factor-alpha inhibitors, B-cell-depleting agents, interferon-alpha, and some antiviral treatments, target specific components of the immune system and may have lower side effect risk profiles than the conventional immunosuppressives and cytotoxic agents. This article addresses the encouraging data and the possible pitfalls of these new therapeutic options, thus far evaluated mostly by case reports, small series, and open-label trials. Confirming the efficacy of existing and newer therapies will require further clinical investigation through randomized placebo-controlled studies to identify the proper doses and treatment schedules and single out those drugs that may expose patients to dangers that outweigh the potential benefits.

PURPOSE OF REVIEW: The aim of this article is to summarize recent clinical, genetic and pathophysiologic findings of familial Mediterranean fever and several of the other systemic autoinflammatory diseases, a recently recognized group of disorders characterized by seemingly unprovoked inflammation but lacking high-titer autoantibodies. Genetic and clinical tools are improving the ability of the clinician to better approach patients with periodic fever and inflammation. RECENT FINDINGS: The spectrum of reported genetic mutations and susceptible ethnicities for the hereditary periodic fever subset of the autoinflammatory diseases has continued to expand. At the same time, the pathogeneses of many of these diseases are now understood to involve different aspects of a common pathway, largely affecting inflammatory cascades related to IL-1 or tumor necrosis factor-alpha. Three of these diseases which have been grouped as the cryopyrin-associated periodic syndromes result from defects in the same gene, and all three appear to respond well to anti-IL-1 therapy although controlled trials are still in progress. In addition, cytokine-based therapies are also now under investigation for hyperimmunoglobulinemia D with periodic fever syndrome and pyogenic sterile arthritis, pyoderma gangrenosum, and acne syndrome. SUMMARY: The identification of the genes and proteins mutated in many of the autoinflammatory diseases has broadened our understanding of the regulation of inflammation and the immune system, and provided the basis for the use of targeted therapies in these syndromes. We propose an algorithm for the evaluation of a patient with periodic fever, taking into account the patient's age, ethnicity, symptoms and signs, and results from laboratory and genetic testing.

Rheumatologic and other musculoskeletal symptoms are prevalent in older patients and often require close attention. Determining early whether an inflammatory or noninflammatory process is involved may help avoid unnecessary morbidity and prevent medication-related toxicities. Physicians should be especially aware of symptoms and signs that suggest giant cell arteritis and look for red flags in patients with low back pain that herald possible infection, visceral disease, or malignancy. Proactive screening and diagnostic testing for osteoporosis are essential to treat older patients and reduce fracture risk

Random V(D)J gene assembly generates many autoreactive B cell receptors (BCRs). In healthy donors, most autoreactive developing B cells are removed either in the bone marrow or in the periphery, revealing two B cell tolerance checkpoints. The regulation and the mechanisms that ensure this human B cell tolerance are poorly characterized, but they require proper BCR signaling. Indeed, patients with X-linked agammaglobulinemia who carry mutations in the BTK gene, which encodes an essential BCR signaling component, fail to establish proper central B cell tolerance, as demonstrated by the release of self-reactive B cells in the periphery. In autoimmune diseases such as rheumatoid arthritis (RA), B cell tolerance is broken and autoantibodies are secreted. Our recent results show that RA patients suffer from defective central and peripheral B cell tolerance checkpoints, which may favor the development of autoimmunity. Also, about half of our RA patients display unusual immunoglobulin light chain repertoires showing impaired secondary recombination regulation, which indicates that receptor editing, one of the mechanisms that normally ensures B cell tolerance, may often be defective in RA.

Autoantibody production is a characteristic of most autoimmune diseases including rheumatoid arthritis (RA). The role of these autoantibodies in the pathogenesis of RA remains elusive, but they appear in the serum many years before the onset of clinical disease suggesting an early break in B cell tolerance. The stage of B cell development at which B cell tolerance is broken in RA remains unknown. We previously established in healthy donors that most polyreactive developing B cells are silenced in the bone marrow, and additional autoreactive B cells are removed in the periphery. B cell tolerance in untreated active RA patients was analyzed by testing the specificity of recombinant antibodies cloned from single B cells. We find that autoreactive B cells fail to be removed in all six RA patients and represent 35-52% of the mature naive B cell compartment compared with 20% in healthy donors. In some patients, RA B cells express an increased proportion of polyreactive antibodies that can recognize immunoglobulins and cyclic citrullinated peptides, suggesting early defects in central B cell tolerance. Thus, RA patients exhibit defective B cell tolerance checkpoints that may favor the development of autoimmunity.

Familial Mediterranean fever (FMF) is a recessive disorder characterized by episodes of fever with serositis or synovitis. The FMF gene (MEFV) was cloned recently, and four missense mutations were identified. Here we present data from non-Ashkenazi Jewish and Arab patients in whom we had not originally found mutations and from a new, more ethnically diverse panel. Among 90 symptomatic mutation-positive individuals, 11 mutations accounted for 79% of carrier chromosomes. Of the two mutations that are novel, one alters the same residue (680) as a previously known mutation, and the other (P369S) is located in exon 3. Consistent with another recent report, the E148Q mutation was observed in patients of several ethnicities and on multiple microsatellite haplotypes, but haplotype data indicate an ancestral relationships between non-Jewish Italian and Ashkenazi Jewish patients with FMF and other affected populations. Among approximately 200 anonymous Ashkenazi Jewish DNA samples, the MEFV carrier frequency was 21%, with E148Q the most common mutation. Several lines of evidence indicate reduced penetrance among Ashkenazi Jews, especially for E148Q, P369S, and K695R. Nevertheless, E148Q helps account for recessive inheritance in an Ashkenazi family previously reported as an unusual case of dominantly inherited FMF. The presence of three frequent MEFV mutations in multiple Mediterranean populations strongly suggests a heterozygote advantage in this geographic region