Clinical Investigations Of Sjogren's Syndrome

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Sjogren's Syndrome (SS) is an autoimmune disease, characterized by widespread inflammation in the exocrine glands and other organs resulting in dryness of the lining surfaces of the body, most notably, dry mouth and dry eyes. In addition, it can involve numerous other organs such as the joints, skin and nervous system. Under this project, the MPTB SS Clinic conducts clinical investigations and clinical trials, and collaborates with laboratory investigators in MPTB, other NIH laboratories and Institutions outside the NIH in order to understand the mechanisms underlying this disease. The ultimate goal of our research is to find treatments for SS that are safe, effective and target specific steps in the pathogenesis of SS. To achieve this goal, we focus our research in two broad categories. Natural history studies include observational and retrospective studies with the goal to expand our knowledge about the pathogenesis of SS, to improve our diagnostic and prognostic tools and to identify targets for new therapies. The other major area involves the evaluation of novel treatments in patients with SS. Natural history studies A major focus of these studies is to evaluate the potential of microRNAs (miRNAs) as biomarkers in SS. We isolated microRNAs from minor salivary glands and saliva and completed miRNA microarray hybridization for 24 tissues and 8 saliva samples. The results allowed us to create a map of microRNAs expressed in minor salivary glands and saliva. Through intensive analysis we identified microRNAs differentially expressed in minor salivary glands from Sjogrens and normal volunteers. We also identified microRNAs differentially expressed in patients with various clinical manifestations. The most promising microRNAs have been validated with TaqMan Quantitative Real Time PCR. Based on our observations about the surprising stability of microRNAs in tissues and saliva when compared to RNA, we explored the use of formalin fixed paraffin embedded tissues as a source of microRNAs. We optimized protocols and successfully isolated microRNAs from paraffin blocks older than thirty years old. This has potentially huge implication since it enables us to use older stored biopsy samples for miRNA analysis. We have continued to expand our DNA bank for patients with SS. This can be used for genetic studies in the future both intramurally and in collaboration with other groups. Currently, we have over 250 DNA samples isolated. In collaboration with the Genomics Branch of NIAMS we published a paper, which, for the first time, has shown that a polymorphism in Stat-4, previously linked to SLE and rheumatoid arthritis, is also associated with SS and may represent a risk factor common to systemic autoimmune diseases. We have also provided DNAs to Dr. John Harleys group in Oklahoma for genome wide association studies in SS. In collaboration with the Neurobiologics and Pain Theraputics Section of NIDCR we tested Sjogrens sera for known and new autoantibodies using a novel highly sensitive immunoprecipitation technology developed in their laboratory. We have shown that this method has a significantly higher sensitivity with as good or better specificity as traditional methods. We also detected antibodies against aquaporin-4 in patients with Sjogrens Syndrome, primarily in those with neurologic manifestations. This observation raises the possibility that anti-AQP4, which is thought to be highly specific for neuromyelitis optica and longitudinal transverse myelitis, may have a role in neurologic manifestations in SS and potentially other autoimmune disorders. Autonomic nervous system (ANS) dysfunction in SS The range of symptoms in SS suggests that there may be perturbations in the nervous and immune systems and in multiple physiological pathways through which these systems communicate and mediate each other. Autoimmunity has been viewed as the most plausible pathogenic mechanism but a significant proportion of patients do not have evidence of systemic autoimmunity, even when followed longitudinally. Compared to normal healthy individuals, SS have significantly more prevalent nervous system involvement including impaired ANS function (which regulates the homeostasis via effects on the smooth muscle, glands and cardiovascular system). However, little is known, about the incidence and prevalence, underlying mechanisms and importance of the ANS in SS patients. In collaboration with the Clinical Neurocardiology Section (NINDS) we started a protocol to investigate ANS function in patients with SS and the association between ANS dysfunction and autoimmunity. We hypothesize that ANS dysfunction is central to the pathogenesis of SS and propose to systematically study the ANS function in our cohort of patients with primary SS compared with normative data from age and sex-matched controls. This protocol consists of a comprehensive evaluation of autonomic function, using physiological, neuropharmacologic, neurochemical, and imaging approaches, to identify consistent distinctive patterns of ANS involvement in SS and thereby improve the diagnosis and understanding of pathophysiologic mechanisms of SS. We have completed testing in 4 subjects. We have also included non-invasive testing of the ANS in the natural history protocol. In the fifty-one SS patients tested sofar we confirmed previous reports of decreased heart rate variability, sympathetic and parasympathetic dysfunction. We also found a paradoxical parasympathetic response to standing which warrants further evaluation in a larger number of patients. MTPB translational research project on Sjogrens Syndrome To narrow the gap between basic science and clinical practice we continued our collaboration with the Adeno-Associated Virus Biology Unit to systematically evaluate the effect of targeted immunomodulation in both patients and animal models of Sjogrens Syndrome. Several projects are underway targeting various molecules, such as TNF alpha, chemokines and anti-M3R antibodies. Our strategy is that by comparing the results from the two approaches we can gain a better understanding of the full therapeutic potential, optimal route of delivery, and biologic impact these molecules may have on the disease. Treatment study using efalizumab (Raptiva) an anti-LFA1 monoclonal antibody Raptiva (efalizumab, Genentech) is an anti-LFA1 monoclonal antibody, which is targeting the LFA1-ICAM pathway that has several functions in Sjogrens Syndrome, including lymphocyte trafficking and antigen presentation. Raptiva is approved for psoriasis but has not been tried in SS yet. During the first three months of the protocol patients are randomized to placebo or Raptiva. This is followed by a 3 month open label phase when everyone receives active drug. Nine patients have been treated in the study, four of which were enrolled during the last year. The protocol uses repeat salivary gland biopsies as part of our response criteria and includes various immunologic assays to address the effect of the treatment on the local and systemic inflammatory process. Future plans We plan to develop several early stage clinical studies (Phase I/II) to establish the safety and toxicity of an intervention, and at the same time, collect data about its possible efficacy. We establish collaborations to combine these clinical trials with thorough basic science evaluations to learn about the pathogenesis of SS and the biologic effects of the intervention. We will continue to collaborate on preclinical studies to enable gene therapy and cellular therapy in the future. In addition to these treatment studies we will do non-interventional clinical studies to address clinical manifestations of Sjogrens Syndrome that are poorly understood and/or not explained by systemic autoimmunity, such as ANS dysfunction and metabolic abnormalities.