The independent JHU cohort proteome data were similarly coded, using combined JHU and validation cohort HC (n=52) to establish positivity thresholds

The independent JHU cohort proteome data were similarly coded, using combined JHU and validation cohort HC (n=52) to establish positivity thresholds. which were detected in both the discovery and validation datasets. Binding to 1 1 of the novel antigens identified 54% of RoSS and 37% of Ro+SS cases, with 100% specificity Gramine in both groups. Machine learning identified 30 novel specificities showing receiver operator characteristic area under the curve of 0.79 (95% CI 0.640.93) for identifying RoSS. Sera from Rocases of an independent cohort bound 17 of the non-canonical antigens. Antigenic targets in both Ro+and RoSS were part of leukemia cell, ubiquitin conjugation, and antiviral defense pathways. == Conclusion == We identified antigenic targets of the autoantibody response in SS that may be useful for Gramine identifying up to half of Ro seronegative SS cases. Keywords:Sjgrens Syndrome, Autoantibodies, Autoimmune Diseases == INTRODUCTION == Primary Sjgrens syndrome (SS) is a systemic rheumatic autoimmune disorder characterized by focal lymphocytic infiltrates in the salivary and lacrimal glands, chronic severe dry mouth and eyes, pain, fatigue, and reduced quality of life.[1,2] The etiology of SS includes genetic predisposition, epigenetic and environmental factors.[3,4] Cardinal features of SS diagnosis or classification require objective measures of ocular and/or oral dryness and either i) the presence of serum autoantibodies to Ro/SS-A[5,6] and/or La-SS-B[7] or ii) focal lymphocytic sialoadenitis as defined by a focus score 1.[58] Approximately one third of SS cases lack serum Ro and La autoantibodies and thus require a minor salivary gland lip biopsy for definitive classification.[9] The requirement for labial salivary gland biopsy to classify SS in Ro/La antibody negative individuals is an important contributing factor to delayed diagnosis of SS, as this procedure is not readily available at many clinical sites. One promising new approach for classifying Ro antibody negative (Ro) SS cases is salivary gland ultrasound (SGUS), which has the added benefit of enabling the measurement of disease-associated changes in the major salivary glands. While SGUS has shown good correlation with labial salivary gland biopsy results, a barrier to widespread implementation in the clinic is high inter-observer variability.[10] Thus, additional approaches for confirming SS in Ropatients are needed. Previous work has shown that autoantibodies secreted by minor salivary gland plasmablasts of SS patients are also present in serum.[11] The presence of salivary gland focal lymphocytic infiltrates[57] and positive serum anti-nuclear autoantibody (ANA) titers[12] in many RoSS cases suggests that autoantibodies of unknown specificity may be present in the circulation and/or saliva of these individuals. Non-Ro/La autoantibodies have been described in SS. Autoantibodies to muscarinic receptor 3 (MR3) that may contribute to salivary gland dysfunction have been identified by a number of Gramine groups,[13] but these antibodies generally occur in Ro antibody seropositive (Ro+) individuals.[14] A trio of SS antigens were first identified in mouse Rabbit Polyclonal to Mst1/2 models and subsequently observed in human patients, including mouse salivary protein 1 (SP-1), carbonic anhydrase 6 (CA6) and parotid secretory protein (PSP).[15] Antibodies to mouse SP-1 were initially reported to occur in over 40% of Ro/La seronegative SS patients and less than 5% of healthy controls.[15] Evaluation in an independent cohort of 123 SS cases showed SP-1 antibodies co-occurred with anti-Ro/La in 34% of cases, in isolation in 19%, and present in 18% of matched regional healthy controls.[16] However, the human parotid antigen recognized by these antibodies remains unknown. Other autoantibodies reported in SS were recently summarized.[17,18] Few studies have attempted unbiased, systematic searches for autoantigens in Ro/La seronegative Gramine SS. Yuan, et al. explored novel autoantibody specificities in SS using Phage Immuno Precipitation technology[19] that detects antibodies to peptides up to 90 amino acids long.[20] This meeting abstract reported two.