AB0683 ROLE OF ELASTIN AND ELASTASE ANTIBODIES IN DEVELOPMENT OF PNEUMOSCLEROSIS IN PATIENTS WITH SYSTEMIC SCLERODERMA
Authors: Olga Rusanova, I Gontar, Olga Emelyanova, Krasilnikov Andrey
Journal: Annals of the Rheumatic Diseases (2019)

<h3>Background</h3> Disturbed elastin metabolism, emerging pathological soluble isoforms followed by triggering of autoimmunity show that the biopolymer under study is associated with the pathogenesis of polyorganic lesions in systemic sclerosis. Elastin catabolism is promoted by elastase, an enzyme with a broad–range substrate specificity. It is the balance of a dynamic elastin–elastase system that determines physiological functioning of organs and tissues containing elastic fibres: the skin, ligaments, lungs, and vascular walls. Antibodies to elastin and elastase are unique predictors of development of pulmonary conditions in systemic scleroderma, which is now considered to be one of risk factors for pulmonary lesion. <h3>Objectives</h3> Developing highly sensitive markers of pulmonary remodeling at early stages of systemic scleroderma with participation of humoral immunity to the elastin–elastase system in the development of pulmonary lesion in systemic scleroderma requires further detailed study. <h3>Methods</h3> Patients for the study were selected from the department of rheumatology at the Emergency Care Municipal Hospital 25 in the city of Volgograd. The main group incorporated 42 persons with the diagnosis of systemic scleroderma verified by aCR/EULAR diagnostic criteria of 2013, without any exclusion criteria. There were 11 men and 31 women aged 22–72 among the systemic scleroderma patients. The mean age of patients was 44.1±15.4. The control group incorporated 30 healthy donors at the Volgograd Regional Blood Transfusion Station. Antibodies to elastin and elastase were determined in the blood serum by indirect enzyme immunoassay utilizing insoluble forms with enhanced antigen content according to the original technique by Gontar et al (1990). <h3>Results</h3> Compared with the control group, patients with systemic scleroderma showed a considerably higher rate of antibodies to elastase (52%) and elastin (38%). The upper normal level of antibodies to elastin was in the range of 0.131 absorbance units, of antibodies to elastase – 0.131 absorbance units. The mean value of elastin antibodies in the blood of systemic scleroderma patients was 0.125 ± 0.068 absorbance units. The value of elastase antibodies was 0.143 ± 0.071 absorbance units. The elevated level of elastin and elastase antibodies in the patients was associated with pulmonary lesion (basal pulmonary fibrosis – 20 (47.6%), pulmonary hypertension – 11 (26.2%), and adhesive pleurisy – 7 (16.7%)). In one half of cases the pulmonary lesion was asymptomatic, detected by accessory investigations like X-ray of chest organs, respiratory function study, EchoCG which were administered to assess the extent of abdominal organ inflammation and in differential diagnosis with cardiac insufficiency. The level of elastin antibodies in systemic scleroderma patients with pulmonary lesion was 0.149 <i>±</i> 0.074 absorbance units, and of elastase antibodies – 0.146 <i>±</i> 0.043 absorbance units, which was considerably higher than mean values in the control group. <h3>Conclusion</h3> By determining antibodies to elastin and elastase by the proposed technique of enzyme immunoassay at early stages of systemic scleroderma one can predict lesions of pulmonary parenchyma presenting with various clinical signs, and exacerbation of fibrosis processes. <h3>Disclosure of interests</h3> None declared