Neuromyelitis Optica: Pathogenesis Overlap with Other Autoimmune Diseases.

PURPOSE OF REVIEW: Neuromyelitis optica (NMO) is an auto-immune disease essentially depicted by optic neuritis and transverse myelitis. Per se, NMO was initially believed to be a sub-type of multiple sclerosis with typical demyelinating cerebral lesions and optic nerve inflammation. More recently, corroborating lignes of evidence have strengthened the concept of the spectrum of diseases associated with NMO and more specifically with the role of anti-aquaporin-4 antibodies in the pathogenesis of disease. RECENT FINDINGS: In this article, we review the recent pathogenic findings in NMO and more interestingly the newly discovered role of anti-aquaporin-4 antibodies as key players in triggering cerebral lesions. The concept of spectrum of diseases associated with NMO is also discussed. These recent findings have paved in the further understanding of the pathogenesis underlying NMO and new treatments are currently being developed targeting anti-aquaporin-4 antibodies.

Involvement of Epithelial-Mesenchymal Transition (EMT) in Autoimmune Diseases.

Epithelial-mesenchymal transition (EMT) is a complex reversible biological process characterized by the loss of epithelial features and the acquisition of mesenchymal features. EMT was initially described in developmental processes and was further associated with pathological conditions including metastatic cascade arising in neoplastic progression and organ fibrosis. Fibrosis is delineated by an excessive number of myofibroblasts, resulting in exuberant production of extracellular matrix (ECM) proteins, thereby compromising organ function and ultimately leading to its failure. It is now well acknowledged that a significant number of myofibroblasts result from the conversion of epithelial cells via EMT. Over the past two decades, evidence has accrued linking fibrosis to many chronic autoimmune and inflammatory diseases, including systemic sclerosis (SSc), rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), Sjögren's syndrome (SS), and inflammatory bowel diseases (IBD). In addition, chronic inflammatory states observed in most autoimmune and inflammatory diseases can act as a potent trigger of EMT, leading to the development of a pathological fibrotic state. In the present review, we aim to describe the current state of knowledge regarding the contribution of EMT to the pathophysiological processes of various rheumatic conditions.

Involvement of IL-33 in the Pathophysiology of Systemic Lupus Erythematosus: Review.

IL-33 is a newly discovered cytokine displaying pleiotropic localizations and functions. More specifically, it also functions as an alarmin, following its release from cells undergoing cell death or necrosis, to alert the innate immune system. The role of IL-33 has been underlined in several inflammatory and autoimmune diseases including systemic lupus erythematosus (SLE). The expressions of IL-33 as well as its receptor, ST2, are significantly upregulated in SLE patients and in patients with lupus nephritis. This review discusses the involvement of IL-33 in the pathology of SLE.

The Involvement of Alarmins in the Pathogenesis of Sjögren's Syndrome.

Sjögren's syndrome (SS) is a chronic autoimmune disease that affects exocrine glands, primarily the salivary and lachrymal glands. It is characterized by lymphoplasmacytic infiltration of the glandular tissues, ultimately leading to their dysfunction and destruction. Besides classic dry eyes and dry mouth defined as sicca syndrome, patients affected by the disease also typically display symptoms such as fatigue, pain and in more than 50% of cases, systemic manifestations such as arthritis, interstitial lung involvement, neurological involvement and an increased risk of lymphoma. The pathophysiological mechanisms underlying SS still remain elusive. The crucial role of innate immunity has been advocated in recent years regarding the pathogenesis of pSS, especially in the initiation and progression toward autoimmunity. Alarmins are endogenous molecules that belong to the large family of damage associated molecular pattern (DAMP). Alarmins are rapidly released, ensuing cell injury and interacting with pattern recognition receptors (PRR) such as toll-like receptors (TLR) to recruit and activate cells of the innate immune system and to promote adaptive immunity responses. This review highlights the current knowledge of various alarmins and their role in the pathogenesis of pSS.

The Involvement of Innate and Adaptive Immunity in the Initiation and Perpetuation of Sjögren's Syndrome.

Sjogren's syndrome (SS) is a chronic autoimmune disease characterized by the infiltration of exocrine glands including salivary and lachrymal glands responsible for the classical dry eyes and mouth symptoms (sicca syndrome). The spectrum of disease manifestations stretches beyond the classical sicca syndrome with systemic manifestations including arthritis, interstitial lung involvement, and neurological involvement. The pathophysiology underlying SS is not well deciphered, but several converging lines of evidence have supported the conjuncture of different factors interplaying together to foster the initiation and perpetuation of the disease. The innate and adaptive immune system play a cardinal role in this process. In this review, we discuss the inherent parts played by both the innate and adaptive immune system in the pathogenesis of SS.

Clinical Profile of Patients with Primary Sjögren's Syndrome with Non-Identified Antinuclear Autoantibodies.

Objectives-The aim of the present study was to characterize the clinical phenotype of patients with primary Sjögren's syndrome (pSS) with non-identified antinuclear antibodies (ANA) in comparison with that of patients with pSS with negative ANA, positive typical ANA (anti-Ro/SSA and/or La/SSB) and positive atypical ANA. Methods-We conducted an observational, retrospective monocentric study at the Erasme University Hospital (Brussels, Belgium). Two hundred and thirty-three patients fulfilling the 2002 American-European Consensus Group criteria for pSS were included in this study. The patients were subdivided according to their ANA profile and demographics. The clinical and biological data of each subgroup were compared. Moreover, the relationships between these data and the ANA profiles were determined by multiple correspondence analysis. Results-In our cohort, 42 patients (18%) presented a non-identified ANA-positive profile. No statistically significant difference could be observed between non-identified ANA patients and ANA-negative patients in terms of age and/or ESSDAI score at diagnosis. There were significantly more frequent articular manifestations, positive rheumatoid factor (RF), and the use of corticosteroids in anti-Ro/SSA-positive patients compared to ANA-negative (p ≤ 0.0001) and non-identified ANA-positive patients (p ≤ 0.01). However, a significantly higher proportion of RF positivity and corticosteroid treatment was observed in non-identified ANA-positive patients compared to ANA-negative patients (p < 0.05). Conclusions-For the first time to our knowledge, our study has characterized the clinical phenotype of patients with pSS with non-identified ANA at diagnosis. The non-identified ANA-positive patients featured mostly a clinical phenotype similar to that of the ANA-negative patients. On the other hand, the non-identified ANA-positive patients were mainly distinguished from the ANA-negative patients by a greater proportion of RF positivity and the need for corticosteroid use due to articular involvement.

Sarcoidosis Versus Lymphoma?

An association between lymphoma and sarcoidosis was first suggested in 1960. We report a case of sarcoidosis-lymphoma syndrome, which is a diagnostically challenging condition. We conclude that an associated lymphoma should be considered in all patients with suspected sarcoidosis, especially those who do not respond to treatment or who present with persistent haematological abnormalities. Splenomegaly should prompt splenectomy to rule out lymphoma if a less invasive approach has failed to confirm the diagnosis. LEARNING POINTS: Clinical consideration should be given to an associated lymphoma in all patients with sarcoidosis, especially those who do not respond to treatment or who present with persistent haematological abnormalities.Splenomegaly should raise the possibility of splenectomy to rule out associated lymphoma.