Ab1236 Case Series of Patients With Systemic Sclerosis and Positive Anti-Centromere Antibodies: Classification and Clinical Manifestations

Background: Systemic sclerosis (SSc) is an autoimmune disease of unknown etiology, characterized by fibrosis in the skin, vascular walls, and certain organs such as the lungs, digestive tract, heart, or kidneys. The disease is classically divided into limited (lcSSc) or diffuse (dcSSc), according to, among other manifestations, the extent of cutaneous involvement. Within lcSSc, the CREST syndrome is described, which includes calcinosis, Raynaud's phenomenon, esophageal involvement, sclerodactyly, and telangiectasia. The most characteristic laboratory finding is the presence of antinuclear antibodies (ANA) in over 95%, with anticentromere antibodies (ACA) being among the most common, appearing in 30-80% of lcSSc and less than 5% of dcSSc. Antibodies in SSc are markers of clinical profiles, and although they are not activity markers, they are related to the prognosis of the disease. Objectives: To determine the prevalence and clinical significance of ACA positivity in patients with suspected systemic autoimmune disease, as well as to describe and analyze the epidemiological variables and clinical manifestations of those patients who meet SSc criteria. Methods: A single-center cross-sectional study was performed, including all patients with positive anticentromere antibodies (ACA) through indirect immunofluorescence (IIF) from 2010 to March 2023. The relationship between the presence of antibodies and the diagnosis of SSc according to ACR/EULAR 2013 criteria was analyzed. In addition, demographic data, clinical diagnoses, and clinical manifestations of patients with SSc were collected, based on the responsible physician's criteria or complementary tests. Skin, pulmonary, digestive, cardiac and renal manifestations, presence of Raynaud's phenomenon, and other manifestations such as neoplasms, acute myocardial infarctions (AMI), strokes, or deep vein thrombosis (DVT) were included; and their prevalence was analyzed. lcSSc was defined as skin hardening in acral areas, distal to elbows and knees, and on the face; and dcSSc as thickening of the skin on the trunk or proximal limb region. Results: A total of 393 patients with positive ACA on IIF were reviewed, with 58 (15%) meeting SSc criteria. Of these 58, 50 were diagnosed with lcSSc (86%), 7 with SSc sine scleroderma (12%), and only 1 with dcSSc (2%). Among lcSSc cases, 7 met CREST syndrome criteria, 4 had overlap syndrome with SSc and Sjögren's syndrome, and 1 was diagnosed with Reynolds syndrome (Primary Biliary Cirrhosis + SSc). Table 1 shows demographic variables collected and diagnostic classifications. Among the different clinical manifestations, Raynaud's phenomenon was present in 100% of patients, of which 41 (71%) had pathological capillaroscopy. Cutaneous manifestations were observed in 66% of patients, followed by digestive manifestations in 53% of cases. Renal involvement was noted in 12%, and cardiac involvement in 10%. Table 2 provides a detailed classification of each domain of manifestations. Table 1. Demographic data and diagnosis of patients with ACA + Table 2. Clinical manifestations SSc patients Conclusion: Fifteen percent of patients with positive ACA met SSc criteria, with 86% classified as lcSSc. Among SSc patients, the majority were women aged 18 to 65 years. The most frequent clinical manifestations were Raynaud's phenomenon (100%), followed by cutaneous manifestations (66%), especially sclerodactyly, telangiectasia, and calcifications. Digestive manifestations (53%), particularly dysphagia and gastroesophageal reflux; and pulmonary manifestations (17%), with pulmonary hypertension standing out, were also notable for their frequency. REFERENCES: 1 Calderon LM, Pope JE. Scleroderma epidemiology update. Curr Opin Rheumatol 2021;33;122-127. 2 Allanore Y, Simms R, et al. Nature review Primer: Systemic Sclerosis. Nat Rev 2015;1:1-21. Acknowledgements: NIL. Disclosure of Interests: None declared.